Die Schwalbe

77 problem(s) found in 3762 milliseconds (displaying 77 problem(s)). [COMMENTDATE>=20200919 AND NOT K='Hilfsrückzüger' AND NOT A='Petrovic, Tomislav' AND S='MatPlus.net Forum'] [download as LaTeX]

1 - P0001924
Bedrich Formanek
Ass. Slovaque 1966
3. Preis
P0001924
(8+2)
#1 (-:
2 Lösungen
1) 1. gxh8=G# justified by history R: 1. Kg6xGh5 & e.g. Gf5-h5+
2) 1. g8=CM# justified by history R: 1. Kg6xCMh5 & e.g. CMe4-h5+
play all play one stop play next play all
Im orthodoxen Schach hat Schwarz keinen letzten Zug. Schwarz muß deshalb im letzten Zug eine Märchenfigur entschlagen haben. Und sehen P1390927
Henrik Juel: something is wrong here: the claimed mates are not even checks
also, the stipulation should probably be something like
Black and White retract, then #1 (2021-04-30)
A.Buchanan: Yes the problem was the word "dann" which indicates help retractor. The retro is just justification for the forward moves, showing that the relevant fairy piece existed earlier in the game so can be promoted to. What's the name of that principle? (2021-05-01)
Henrik Juel: Thanks for the clarification, Andrew
I think that this principle should remain unnamed and just stay in the joke realm (2021-05-01)
A.Buchanan: Sorry not to be clear: I am talking about the standard fairy principle that if you want to promote to a Princess, there should be one on the problem diagram. Not talking about the joke extension which riffs off this. I thought this was called "Bartel Theme", but it turns out that is something different. (2021-05-01)
Henrik Juel: I see; that principle probably was established soon after the invention of grasshoppers and nightriders
I do not think it has a name, but it is so well established that it should be in the Codex (2021-05-01)
more ...
comment
Keywords: Joke, Last Moves?, Minimal
Pieces: du = Grasshopper (G), lu = Camel (CM)
Genre: Retro, Fairies
FEN: 7b/6P1/7B/6Pk/2P5/3B3K/2P1P3/8
Reprints: (17) diagrammes 97 04-06/1991
MatPlus.net Forum 6/4/2021
Input: Gerd Wilts, 1995-06-03
Last update: A.Buchanan, 2021-06-19 more...
2 - P1108961
Bedrich Formanek
Schach-Echo 11/1972
P1108961
(8+56) C+
h#2
2.1.1.1
wDU,sDU=Grashüpfer
1) 1. Ga5xa7 Gb7xd5 2. Gd7-b7 Ge8xc8#
2) 1. Gd7xb7 Ga7xa5 2. Gc7-a7 Ge8xc8#
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volles Haus
Ladislav Packa: A decent parody of the (new at the time) rule about any number of fairy units on the board. (2021-05-01)
more ...
comment
Keywords: Full House, Aristocrat
Pieces: du = Grasshopper (G)
Genre: Fairies
Computer test: C+ Popeye 4.61
FEN: k*2q*2q*2q*2Q*2Q*2q*2q/*2Q*2Q*2q*2q*2q*2q*2q*2q/*2q*2q*2q*2q*2q*2q*2q*2q/*2q*2q*2q*2q*2q*2q*2q*2q/*2Q*2q*2Q*2q*2q*2q*2q*2q/*2q*2q*2q*2q*2q*2q*2q*2q/K*2q*2Q*2q*2q*2q*2q*2q/*2q*2q*2q*2q*2q*2q*2q*2q
Reprints: B) Problemkiste (70) 08/1990
V5) Problemkiste (187) 02/2010
MatPlus.net Forum 6/4/2021
Input: Erich Bartel, 2010-06-27
Last update: A.Buchanan, 2021-05-02 more...
3 - P1255936
Arno Tüngler
13940 Die Schwalbe 234 12/2008
Lob
P1255936
(11+16) C+
ser-A=>B in 320 Zügen
1. Ka4 2. Lc2 3. Ld1 4. Le2 5. Lf1 6. Lh3 7. Lg4 8. Lh5 9. Le8 10. Ld7 11. Lc8 12. La6 13. Lxb5 14. La6 15. Lc8 16. Ld7 17. Le8 18. Lh5 19. Lg4 20. Lh3 21. Lf1 22. Le2 23. Ld1 24. Lb3 25. Kb4 26. Kc3 27. Lc2 28. Kd2 29. Kd1 30. La4 31. Lb5 32. La6 33. Lc8 34. Ld7 35. Le8 36. Lh5 37. Lg4 38. Lh3 39. Lf1 40. Le2 41. Ke1 42. Kf1 43. Kg2 44. Kh3 45. Ld1 46. La4 47. Lb5 48. La6 49. Lc8 50. Ld7 51. Le8 52. Lh5 53. Lg4 54. Kh4 55. Kh5 56. Lh3 57. Lf1 58. Le2 59. Ld1 60. La4 61. Lb5 62. La6 63. Lc8 64. Ld7 65. Le8 66. Lg6 67. Kh6 68. Kg7 69. Lf7 70. Kf8 71. Ke8 72. Lh5 73. Lg4 74. Lh3 75. Lf1 76. Le2 77. Ld1 78. La4 79. Lb5 80. La6 81. Lc8 82. Ld7 83. Kxd8 84. Ke8 85. Lc8 86. La6 87. Lb5 88. La4 89. Ld1 90. Le2 91. Lf1 92. Lh3 93. Lg4 94. Lh5 95. Lf7 96. Kf8 97. Kg7 98. Lg6 99. Kh6 100. Kh5 101. Le8 102. Ld7 103. Lc8 104. La6 105. Lb5 106. La4 107. Ld1 108. Le2 109. Lf1 110. Lh3 111. Lg4 112. Kh4 113. Kh3 114. Lh5 115. Le8 116. Ld7 117. Lc8 118. La6 119. Lb5 120. La4 121. Ld1 122. Le2 123. Kg2 124. Kf1 125. Ke1 126. Kd1 127. Lf1 128. Lh3 129. Lg4 130. Lh5 131. Le8 132. Ld7 133. Lc8 134. La6 135. Lb5 136. La4 137. Lc2 138. Kd2 139. Kc3 140. Lb3 141. Kb4 142. Ka4 143. Ld1 144. Le2 145. Lf1 146. Lh3 147. Lg4 148. Lh5 149. Le8 150. Ld7 151. Lc8 152. La6 153. Lb5 154. Kxa5 155. Ka4 156. La6 157. Lc8 158. Ld7 159. Le8 160. Lh5 161. Lg4 162. Lh3 163. Lf1 164. Le2 165. Ld1 166. Lb3 167. Kb4 168. Kc3 169. Lc2 170. Kd2 171. Kd1 172. La4 173. Lb5 174. La6 175. Lc8 176. Ld7 177. Le8 178. Lh5 179. Lg4 180. Lh3 181. Lf1 182. Le2 183. Ke1 184. Kf1 185. Kg2 186. Kh3 187. Ld1 188. La4 189. Lb5 190. La6 191. Lc8 192. Ld7 193. Le8 194. Lh5 195. Lg4 196. Kh4 197. Kh5 198. Lh3 199. Lf1 200. Le2 201. Ld1 202. La4 203. Lb5 204. La6 205. Lc8 206. Ld7 207. Le8 208. Lg6 209. Kh6 210. Kg7 211. Lf7 212. Kf8 213. Ke8 214. Lh5 215. Lg4 216. Lh3 217. Lf1 218. Le2 219. Ld1 220. La4 221. Lb5 222. La6 223. Lc8 224. Ld7 225. Kd8 226. Kc8 227. Le8 228. Lh5 229. Lg4 230. Lh3 231. Lf1 232. Le2 233. Ld1 234. Lb3 235. Kb7 236. Kxa7 237. Kb7 238. Kc8 239. Ld1 240. Le2 241. Lf1 242. Lh3 243. Lg4 244. Lh5 245. Le8 246. Ld7 247. Kd8 248. Ke8 249. Lc8 250. La6 251. Lb5 252. La4 253. Ld1 254. Le2 255. Lf1 256. Lh3 257. Lg4 258. Lh5 259. Lf7 260. Kf8 261. Kg7 262. Lg6 263. Kh6 264. Kh5 265. Le8 266. Ld7 267. Lc8 268. La6 269. Lb5 270. La4 271. Ld1 272. Le2 273. Lf1 274. Lh3 275. Lg4 276. Kh4 277. Kh3 278. Lh5 279. Le8 280. Ld7 281. Lc8 282. La6 283. Lb5 284. La4 285. Ld1 286. Le2 287. Kg2 288. Kf1 289. Ke1 290. Kd1 291. Lf1 292. Lh3 293. Lg4 294. Lh5 295. Le8 296. Ld7 297. Lc8 298. La6 299. Lb5 300. La4 301. Lc2 302. Kd2 303. Kc3 304. Lb3 305. Kb4 306. Ka4 307. Ld1 308. Le2 309. Lf1 310. Lh3 311. Lg4 312. Lh5 313. Le8 314. Ld7 315. Lc8 316. La6 317. Lb5 318. Ka5 319. a4 320. Ld4+
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Das ist nur die Stellung A.
Zielstellung B: ss6/4B3/2BtTt2/KLtk1TB1/B1lL1d2/3BtB2/1t6/2s3l1 (Forsythe-Notation mit deuschen Steinbezeichnern)

Preisrichter Sven Trommler in Die Schwalbe Dezember 2010:
Dass es bei dieser Aufgabe eher um eine Rekordjagd als um ein pointiertes Problem geht, zeigt das verwendete Material sowie der in der Diagrammstellung im Schach stehende weiße König.
Arno Tüngler: Neuer Rekord siehe P1362217 (2024-01-05)
comment
Keywords: Seriesmover, A to B
Genre: Fairies
FEN: nn1b4/p3P3/2PrRr2/nnrkBRP1/1Kb2q2/P2PrP2/1r6/1Bn3b1
Reprints: MatPlus.net Forum 11/04/2009
My problems [Arno Tüngler] , p. 242, 06/2009
1 feenschach 176, p. 42, 04-06/2009
Die Schwalbe 246, p. 696, 12/2010
Input: Gerd Wilts, 2012-12-13
Last update: Arno Tüngler, 2024-01-05 more...
4 - P1354596
Per Olin
MatPlus.net Forum 17/04/2018
P1354596
(16+16)
Position after 18.0 moves
Chess960
Game array?
Per Olin: Here is asked for the Chess960 initial position, the play is not unique. Solution:

Both parties have made 8 pawn moves and 10 moves with all the other pieces, i.e. on both sides two of the officers have made two moves or one has made three moves (castling counts as a king's move). Finding out which pieces have moved once and which pieces have moved more than once helps in determining the initial positions of all pieces.

- In the diagram position there are three knights on dark squares and one on light squares; this means that a knight has moved twice (or three knights moved twice or same knight three times).

- The wLg2 and bLc7 come from the same file and consequently one of these bishops (or both of them) has (have) made two moves.

- If there were no castling(s) made, then the kings would need five moves, which taking into account the above, would be too many. At least one castling has taken place and thus at least one of the kings has made two moves.

- There are two possibilities for the fourth and last piece to have moved twice: a) the bishops wLf2 and
bLd7 have started on e1/e8 and then bTe7 has moved twice or b) the bishops wLf2 and bLd7 have not started on e1/e8 and one of them has moved twice. In the latter alternative, e.g. initial positions DTLSKLST and DLSSTKLT, White can reach his diagram position of the officers in 10 moves , but Black can not. Alternative b) is impossible and consequently the fourth piece to have moved twice is the rook on e7.

Summing up: the pieces to move twice are 1) a knight 2) wLg2 or bLc7 3) one of the kings and 4)bTe7.

Conclusions: - wLf2 and bLd7 start on e1/e8 - the uniting file for two knights is the c-file with knights starting on c1/c8 - the previous means that either wSb2 or bSg7 has made two moves by starting on d- or e-file; as the e-file is occupied by bishops, then the knights start on d1/d8 - the black pieces making two moves are bTe7 and bSg7; the white pieces making two moves are wKc2 and wLg2; one of the moves by wK is c-side castling - the previous excludes bLc7 from making two moves meaning that it has started on b8 or d8 and from this follows that wLg2 has started either on b1 or d1; this can not be d1 as it is reserved for a wS and therefore there is a wL on b1 - with bishops on b1/b8 the queens must start on a1/a8 - the black king moves from its initial position g8 to h7 - a black rook is on h8 and, as bTf7 moves only once, the other rook is on f8.

Solution: The sought Chess960 initial position is DLSSLTKT (the moves in addition to the pawn moves are for White 0-0-0, Da1-a2, Sd1-b2, Kc1-c2, Td1-d2, Sc1-e2, Le1-f2, Lb1-e4, Le4-g2, Th1-h2 and for Black Sc8-a7, Da8-b7, Lb8-c7, Le8-d7, Th8-e8, Te8-e7 , Tf8-f7, Sd8-e6, Se6-g7, Kg8-h7). (2021-01-26)
comment
Keywords: Chess960, Castling
Genre: Retro, Fairies
FEN: 8/nqbbrrnk/pppppppp/8/8/PPPPPPPP/QNKRNBBR/8
Input: A.Buchanan, 2018-08-29
Last update: Alfred Pfeiffer, 2018-09-05 more...
5 - P1370911
James Malcom
Andrew Buchanan

(4) MatPlus.net Forum Retro/Math 21/12/2019
P1370911
(12+14)
PG in 12.5
(-:
1. e4 d5 2. e5 Dd6 3. exd6 Kd7 4. dxe7 Kc6 5. Lb5+ Kxb5 6. c4+ Kxc4 7. e8=T Kd3 8. Df3+ Kc2 9. d3 Lh3 10. Ld2 Lxg2 11. Lb4 Lxh1 12. Sc3 Lg2 13. 0-0-0-0-0-0#
play all play one stop play next play all
http://matplus.net/start.php?px=1609818957&app=forum&act=posts&fid=xshowr&tid=2402&pid=20379#n20379
Objective: Staugaard (Pam-Krabbé) castling as mating move.
more ...
comment
Keywords: Unique Proof Game, Staugaard castling, Joke, Prenix, Promotion (T), Castling as mating move, Superseded by (P1385595)
Genre: Retro, Fairies
Computer test: C+ Natch 3.1 has no solutions in 12.5 moves & 1 solution for first 12.0 moves. (H.Juel)
FEN: rn3bnr/ppp2ppp/8/3p4/1B6/2NPKQ2/PPk1RPbP/R5N1
Input: A.Buchanan, 2019-12-23
Last update: James Malcom, 2022-02-26 more...
6 - P1371538
Miodrag Mladenovic
MatPlus.net Forum 14/11/2019
P1371538
(11+9) C+
s#15
1. e8=D+! Kxe8 2. Sd6+ Kxd7 3. c8=L+ Kc6 4. Tc7+ Kxd6 5. Tc6+ Kd5 6. Td6+ Ke5 7. Td5+ Ke4 8. Te5+ Kf4 9. Tf5+ Kg4 10. Tf4+ Kg3 11. Tg4+ Kh3 12. Tg3+ Kh2 13. Txg2+ Kh1 14. Tg1+ Kxg1 15. Dg3+ Dxg3#
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Record of 14 consecutive double checks in a selfmate

Record of a 14 square route of the Black king
SCHRECKE: For which category is it a length record? (2020-01-06)
SCHRECKE: 1.e8D+! K:e8 2.Sd6+ K:d7 3.c8L+ Kc6 4.Tc7+ K:d6 5.Tc6+ Kd5 6.Td6+ Ke5 7.Td5+ Ke4 8.Te5+ Kf4 9.Tf5+ Kg4 10.Tf4+ Kg3 11.Tg4+ Kh3 12.Tg3+ Kh2 13.T:g2+ Kh1 14.Tg1+ K:g1 15.Dg3+ D:g3# (2020-01-07)
Anton Baumann: Autor: Doppelschach (konsekutiv 14-fach), Königstreppe (2020-01-07)
Henrik Juel: Popeye 4.61 with 'opt nichtt 0 1' found no flaws (2020-01-07)
SCHRECKE: C+, Gustav 4.1a, Brute Force (2020-01-08)
James Malcom: This also has, to my current knowledge, the long route of the Black king in a s#, at 14 different squares visited. (2021-01-01)
comment
Keywords: Move Length Record, konsekutive Umwandlungen 2 (DL), under-promotion (L)
Genre: s#
Computer test: Gustav 4.1a, Brute Force
FEN: BQN3N1/1RPRPk2/1B6/1b4np/2nr3r/4q3/4P1p1/4K3
Input: A.Buchanan, 2020-01-06
Last update: James Malcom, 2021-01-01 more...
7 - P1372578
Henry John Clinton Andrews
293 Chess Player's Chronicle , p. 234, 1879
P1372578
(5+6)
Remis
1. Sf7! Txf7 2. Ka8 Txc7 3. b8=B! ... Patt
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Alfred Pfeiffer: Bis 1904 war nach den Regeln eine "Umwandlung" in Dummy-Bauer erlaubt.

1862 British Chess Association rule:
"Code of Laws of the British Chess Association" In that code, Law XIII said, "When a pawn has reached the eighth square, the player has the option of selecting a piece, whether such piece has previously been lost or not, whose names and powers it shall then assume, or of deciding that it shall remain a pawn."

Die Umwandlung in Dummy-Bauer wure erst 1904 offiziell abgeschafft. Daher würde ich bei Aufgaben aus jener Epoche nicht von "Scherzaufgaben" oder "Umwandlungsscherzen" sprechen. (2020-02-12)
James Malcom: While you are correct, it is the best possible classification for them in the modern era in my opinion. We shall speak of them as such, but shall we at least classify them as such? (2020-02-12)
Mario Richter: Alfred is only partially correct: this strange Law XIII was only valid in the British Chess Association - many other countries had rule sets without allowing dummy pawns (e.g. Germany, Russia, France, to name a few). Or to put it with the words of the 'Philadelphia Times' 03.01.1886 p.7: "the 'Dummy pawn' code of 1862 ... , has never, outside of a very limited circle, received any recognition."
I have nothing against the classification as "joke" and "joke promotion", since we're classifiying the problems from a today's perspective.
In an alternative for is to be found, Daniel VanArsdale, in his Web-article about Loyd's dummy pawn problem (P1265742) uses the term "Liberated promotion" (s. a href="http://www.silcom.com/~barnowl/Sam_Loyd%27s_Dummy_Promotion.html"http://www.silcom.com/~barnowl/Sam_Loyd%27s_Dummy_Promotion.html/a) (2020-02-12)
A.Buchanan: Mario, thanks for the link to VanArsdale's sympathetic article. You allow that a Dummy Pawn problem can be a joke, but so could *anything*, so you conceded nothing. We can do much better than this to respect the diversity of our history, our present and our future. Key idea: there is nothing about "today's perspective" that warrants special treatment.

Different rule sets, different generations of FIDE Laws, different Codex editions, different individuals across time and space are in fundamental disagreement about relatively minor aspects of the rules and problem conventions. A random example today is that the problem world silently ignores the USCF Laws. Is this fair? Probably not. Because their assumptions disagree with one another, not all problems can be "orthodox". But to say that the punishment for losing a theological debate is to be banished to the realms of fairy or joke is too great. It makes a completely unnecessary and cruel zero-sum game of the business.

I think there is merit in moving beyond these secondary squabbles to find a "canonical" set of problem chess rules (1) as a foundation for fairy chess (2) a basis for programming, especially retro conventions and (3) a more comprehensible world for newcomers who are increasingly attracted to our hobby. How to do this without theological acrimony? This canonical set should involve a minimum of imposition: it should based on be a careful but not over-literal reading of the FIDE Laws and Codex today, and grounded in a formal specification language to avoid ambiguity. I've got a plan for this and have shared the first pseudo-code draft with some people already. If you are interested, please get in touch.

So what about problems that don't fit? As a principle, I propose that all problems which were for some group or at some time completely legal and orthodox can *never* lose that status. They are in a special immortal class: "Golden Age". They are neither joke nor fairy, neither illegal nor unsound. They are both orthodox and unorthodox. And we record carefully how each such problem class differs from the canon. We make sure they never become unintelligible. Some are historical but many are being composed today, and there is no shame attached to them. They light up the evolutionary journey of our hobby, and in their rarity they are in some ways more interesting than the vast number of orthodox problems which may be forgotten more quickly.

If a Golden Age problem is submitted to a tourney today, then the "genre" would probably be fairy or retro, but of course this classification is the coarsest level of roll-up for tourney purposes only, and does not mean that the nature of the problem is necessarily fairy or retro.

Dummy Pawn was enjoyed by some, including World Champion Wilhelm Steinitz, and excited wrath among others, including World Champion wannabe Howard Staunton. Now that the dust of controversy from the 1800s has settled, its value today is (1) as a fresh, fecund and paradoxical design space and (2) as a relatively uncontroversial poster-child prototype for Golden Age as a mechanism to allow us all to better agree to disagree. (2022-02-08)
comment
Keywords: Dummy Pawn, Golden Age (Dummy Pawn)
Genre: Studies
FEN: 1K5N/pPP3rr/8/6p1/8/4p1k1/4P3/8
Reprints: (14) MatPlus.net Forum 13/5/2020
Input: James Malcom, 2020-02-11
Last update: A.Buchanan, 2023-08-04 more...
8 - P1373235
Samuel Loyd
E50 The New York Clipper , p. 390, 28/03/1857
P1373235
(7+10) cooked
#5
1. Dxa3+! Kc2 2. Dxb3+ Txb3 3. Se3+ fxe3 4. Lxd3+ Kxd3 5. 0-0-0#
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Cook: Dual
2. Ta2+ Tb2 3. Txb2+ Kc1 4. Ta2+,Th2+,Tg2+,Tf2+,Te2+,Td2 Kb1 5. Sxc3#
"Trick 'o the trade.".
James Malcom: This is the oldest known problem that features the Belen theme. (2020-09-20)
comment
Keywords: Capture key, Castling as mating move (wl), Checking key, Sacrifice of white pieces, Belen Theme
Genre: n#
FEN: 3b4/8/7r/6q1/R4p2/nnpb4/Q7/RrkNKBN1
Reprints: (5) MatPlus.net Forum 3/10/2019
Input: Felber, Volker, 2020-03-08
Last update: James Malcom, 2020-09-21 more...
9 - P1374103
James Malcom
MatPlus.net Forum 26/12/2019
“A Tripley For The Holidays”
P1374103
(7+12) C+
h#3
(-:
3.1
1) 1. Se7 Lxh4 2. 0-0 Lxf6 3. Tf7 Th8#

2) 1. La7 b6 2. 0-0-0 bxa7 3. Td7 a8=D#

3) 1. e1=T Lf1 2. 0-0-0-0-0-0! Lxd3 3. Kd5 Lc4#
play all play one stop play next play all
All three castlings in a helpmate on the same move. Compare to P1227518.

http://matplus.net/start.php?px=1609949816&app=forum&act=posts&fid=gen&tid=2409
A.Buchanan: WinChloe rokagogo only finds the intended solutions, no real P-M duals and no fake rokagogo duals:
1.Cé7 F×h4 2.Rg8(Tf8) F×f6 3.Tf7 Th8‡
1.é1=T Ff1 2.Ré6(Té7) F×d3 3.Rd5 Fç4‡
1.Fa7 b6 2.Rç8(Td8) b×a7 3.Td7 a8=D‡ (2021-01-06)
more ...
comment
Keywords: Joke, Staugaard castling, Castling, Promotion in the mating move (D), under-promotion key (T), Castling as mating move
Genre: h#, Fairies
Computer test: Henrik Juel: Solutions 1 and 2 are C+ by Popeye 4.61 C+ WinChloe Rokagogo: no real P-M duals and no fake Rokagogo duals
FEN: rb2k1nr/2p5/3p1p2/1P3p2/5P1p/1K1p1P1R/4pBB1/8
Input: James Malcom, 2020-04-02
Last update: A.Buchanan, 2024-01-18 more...
10 - P1375654
Andrew Buchanan
(2) MatPlus.net Forum 09/05/2020
in memory of Wilhelm Steinitz
P1375654
(13+14) C+
PG in 8.0 (-:
1. f4 a5 2. f5 a4 3. f6 a3 4. fxe7 axb2 5. exf8=B! bxa1=L 6. Lb2 Ke7! 7. Lf6+ Ke6! 8. Sc3 Dxf8!
play all play one stop play next play all
Henrik Juel: The solution is almost given away by the keywords
1.f4 a5 2.f5 a4 3.f6 a3 4.fxe7 axb2 5.exf8! bxa1=L 6.Lb2 Ke7 7.Lf6+ Ke6 8.Sc3 Dxf8
Even though Black captures the white man on f8, promotion to DTLS will not work
First Schnoebelen with dummy pawn as the captured man, I would think
Very good, Andrew (2020-05-08)
Henrik Juel: Another first:
Never before was a problem commented in the PDB before it was published... (2020-05-08)
James Malcom: When Andrew messaged me this asking about a PG with two dummies, I came back almost right away with the same idea, albeit in a flawed form-1. a4 f5 2. a5 f4 3. a6 f3 4. axb7 fxe2 5. bxa8=Q exd1 6. Ke2 e6 7. Ke3 Qg5+ 8. Kd4 Qxg2 9. Qf3 Qxh1 10. Qxd1. Great minds think alike after all! The best way. I think, to have two dummies is to have one per side and have both kings make the same journey. An idea to make it all unique is the problem though. (2020-05-08)
A.Buchanan: Haha Henrik thank you. Well I'm in lockdown in Singapore, and it was 9-May already when I posted in Matplus. (2020-05-09)
A.Buchanan: Can claim that this is not Schnoebelen because the pawn wasn't promoted! Just remained as a pawn! But I'm sure the Schnoebelen theme was interpreted in a looser sense in 1860s. Although exponents in that era would have been baffled as to *why* the theme was termed "Schnoebelen", as Philippe was not yet born. (2020-05-09)
Henrik Juel: I am sorry to learn about the Singapore lockdown, but here the merriment has no bounds (apart from the notational dilemma: exf8 is not a promotion and still the PDB animation requires exf8=B) (2020-05-09)
Olaf Jenkner: If you consider each pawn move onto the 8th rank as a promotion then we have the Schnoebelen. (2020-05-09)
A.Buchanan: This is not "non-standard material", removing that keyword. (2022-01-26)
more ...
comment
Keywords: Unique Proof Game, Schnoebelen Theme (B), Phoenix (l), Prentos Theme (B), Ceriani-Frolkin Theme (B), Dummy Pawn, Golden Age (Dummy Pawn), Promotion (Bl)
Genre: Retro
Computer test: Jacobi v0.7.4 2020-05-08
FEN: rnb2qnr/1ppp1ppp/4kB2/8/8/2N5/P1PPP1PP/b2QKBNR
Input: A.Buchanan, 2020-05-08
Last update: A.Buchanan, 2023-08-04 more...
11 - P1377152
J. B. McKim
Andrew Buchanan

MatPlus.net Forum 20/6/2020
JBMcK, correction AB
P1377152
(6+4) C+
#2
1. Sc7! zz
1. ... Lxe7 2. Sb5#
1. ... Lxc7 2. Sc8#
1. ... Kxc7 2. Df4#
1. ... Kxe7 2. Dc5#
play all play one stop play next play all
Correction of 317 American Chess Journal, p. 49, 07-08/1877
See P1213947
A.Buchanan: 2-for-1 flight exchange + sacrificial key, together with the asymmetrical position perhaps compensates for the cook-blocking tied pawn pair on a4/a5 (2021-07-06)
more ...
comment

Genre: 2#
Computer test: Popeye 4.61
FEN: 3bB3/4N3/K2k1p2/p2N1Q2/P7/8/8/8
Input: A.Buchanan, 2020-06-20
Last update: A.Buchanan, 2021-07-06 more...
12 - P1378636
James Malcom
Facebook 22/07/2020
P1378636
(9+5)
Promotion to king or queen, depending on location (-:
#2
1. h8=DK!
1. ... Lxc3 2. DKxf6xd4xb2#
1. ... Lc5, L~ 2. Lxe5#
play all play one stop play next play all
A.Buchanan: Hi James, tiny point. Does 1. ... La7 allow both 2. GKxf6xd4# and 2. Lxe5# ? Can this be fixed by shifting wBc7 to b8? (2023-07-01)
comment
Keywords: Draughts / Checkers (Englisch), Joke, Joke promotion (draughts king)
Pieces: ku = Draughts King (DK)
Genre: 2#, Fairies
FEN: 8/2B3pP/6P1/4p3/3b4/2P1p2P/4P1Bk/5K1N
Reprints: MatPlus.net Forum 22/07/2020
Input: A.Buchanan, 2020-07-31
Last update: A.Buchanan, 2023-08-11 more...
13 - P1378638
Joost de Heer
MatPlus.net Forum 25/07/2020
P1378638
(4+5)
Unknown Russian composer
Promotion to king or queen, depending on location (-:
#1
Joost de Heer: In russian draughts, a piece promoting to a draughts king may continue the capture as a king if possible.
Solution: 1. e7# (double check by e7xd8=DKxb6xf2/g1 and e7xf8=DKxh6xd2/c1). (2022-01-19)
comment
Keywords: Draughts / Checkers (Russian), Joke, Joke promotion (DR)
Pieces: ku = Draughts King (DK)
Genre: Fairies
FEN: 3n1n2/2p3p1/4P3/8/8/4kP2/4P3/3K4
Input: A.Buchanan, 2020-07-31
Last update: A.Buchanan, 2023-08-11 more...
14 - P1379376
James Malcom
(30) MatPlus.net Forum 26/8/2020
P1379376
(13+13) C+
BP in 11.0
(-:
1. f4 b5 2. f5 b4 3. f6 b3 4. fxe7 bxc2 5. exf8=B cxb1=L 6. Da4 Ke7 7. Dh4+ Ke6 8. g4 Se7 9. Lg2 Txf8 10. Lb7 Sc6 11. Lxc8 Tb8
play all play one stop play next play all
Henrik Juel: What is the joke, James?
Natch 3.1 found no solution (2020-08-26)
James Malcom: The solution has now been added in, Henrik.

This PG has two purposes.
1) It is another exploration of what themes be realized with the dummy pawn involves.
2) It is also to push the boundaries of how long a dummy pawn PG can be made. (2020-08-27)
Henrik Juel: Thanks, James
Apparently you also extended the proof game; the one I tested was in 10.5
The solution shows the Schnoebelen theme, by the way (2020-08-27)
Henrik Juel: You forgot to remove wPf2 from the diagram position (2020-08-27)
James Malcom: Removed, and yes I did manage to find a way to extend it by a ply, in theme for its purpose. The version is also C+. (2020-08-27)
A.Buchanan: I think sLb1 is kind of anti-Belfort Any way to replace it with a Phoenix/Prenix knight? (2020-08-27)
Henrik Juel: Strictly speaking, this is not Belfort, which requires two units to stand away
As Andrew suggests, if sLb1 were a black knight, we would have Belfort (2020-08-27)
A.Buchanan: It's limiting to just talk about Belfort Theme - one historical tourney which had a fiddly constraint about the number of pieces exhibiting the property. Want really to talk more generally about Belfort *Effect*, which is a property of a single unit (2022-01-26)
comment
Keywords: Belfort (L), Dummy Pawn, Schnoebelen Theme, Golden Age (Dummy Pawn), Ceriani-Frolkin Theme (B), Prentos Theme (B), Unique Proof Game, Non-standard material (l)
Genre: Retro
Computer test: Jacobi v.0.7.5
FEN: 1rBq1r2/p1ppnppp/2n1k3/8/6PQ/8/PP1PP2P/RbB1K1NR
Input: James Malcom, 2020-08-26
Last update: A.Buchanan, 2023-08-04 more...
15 - P1380122
Zalmen Kornin
Kibitzer's Cafe 5/8/2004
P1380122
(9+5) C+
#4
1. g8=D! d5 2. exd6ep Kc2 3. Sxc3 Kd3,Kb2 4. 0-0-0#,Dxa2#
play all play one stop play next play all
Final development of the earlier P1380121

https://www.chessgames.com/perl/chessforum.pl?kpage=587&archive=1#kibitzing

"For those interested in Chess Problems: In Tim Krabbé's "Open Chess Diary" the investigation on an idea in Composition, the so called "Belén-Theme" goes on with more novelties; - i'm arriving from that chess-cyber-café... i found that Problemist, he asked me "do You know the Valladão-Theme?" - Yes, i knew that jargon: "The Problem is pronto" What? "Ready" He showed me and asked me to publish here (is related to the previous ones) Author: Z. Kornin; "The Kibitzer's Café" 2004, Original - White: Ke1, Ra1, Bd4, Nb1, Pb6, Pc5, Pe5, Pg4, Pg7 (9); Black: Kc1, Pa2, Pc3, Pc6, Pd7 (5) - Mate in 4 , or in Forsyth: 8-3p2P1-1Pp5-2P1P3-3B2P1-2p5-p7-RNk1K3 (9+5) #4 < the key introduces a threat against 'a2', 'b3' and 'c4' , there are two related thematical variations, following a scheme aAbB - bBaA in the second and third moves; the sideline defenses 2...axb1 or 2...Kb2 in the 1...d5 variation are not total stops from the initial threats; in the en-passant moment there's a choice too: 3.cxd6 ep? c5! and Black will not fall in zugzwang; so 3.exd6!! - this effects springs from a natural setting - the Pawn 'c6' is necessary to stop an eventual Qxd5... Pawns 'b6' and 'g4' prevents duals in thematical play, other features are similar to the Author's scheme from "The Kibitzer's Café" July, 29 - see above Page 566.> The last chapter from a Chess-Composition workshop on-line!!"

Konig and Turm: ""Noch im Jahr der Thema(*)-Entdeckung (*the Belén) gelang dem Brasilianer Kornin eine Darstellung mit dem Valladão-Task" Hanspeter Suwe (2007);" (quote taken from here-https://www.chessgames.com/perl/chessuser?uname=vonKrolock)

Tim Krabbe's minuscule mention in #253 in a small edit to the 7/28 P.S: "(NB: see pages 566 [P1380121 ] and 587 of that forum for the on-line development of a Valladao-Belén.)"


http://www.berlinthema.de/Auswahl_PH.pdf-"Das Belén-Thema verlangt den schwarzen Königsmarsch von c1 nach d3 gefolgt von der weißen langen Rochade – wie P.H. richtig anmerkt, sollte man besser von einem „Motiv“ sprechen. Kornins Stück verbindet dieses Motiv vermutlich erstmalig mit einem Valladao.
Auf mich wirkt ein Valladao mit Damenumwandlung allerdings immer „halb“, denn der „eigentliche“ Sonderzug ist doch eine Unterverwandlung? Eine solche würde auch einen selbstverständlichen Schlüssel verhindern."
James Malcom: This is the first Valladao-Belen: the Belen theme plus promotion and en passant. (2020-09-21)
Henrik Juel: Only the cases with Black defending by d7-d5 and Kc1-c2 in his first two moves lead to dual-free full-length variations (2020-09-21)
comment
Keywords: Belen Theme, Valladao Task, En passant, Promotion key, Castling as mating move
Genre: n#
FEN: 8/3p2P1/1Pp5/2P1P3/3B2P1/2p5/p7/RNk1K3
Reprints: H48a Der Reiz des Ungewöhnlichen
König & Turm 22, p. 14, 5/2007
(15) MatPlus.net Forum 8/9/2019
Input: James Malcom, 2020-09-21
Last update: James Malcom, 2020-10-27 more...
16 - P1380125
James Malcom
(1) MatPlus.net Forum 29/8/2019
P1380125
(8+6) C+
s#6
1. Sd3+! Kc2 2. Tc5+ Kxd3 3. Dd6+ Ke4 4. Sc3+ bxc3 5. De5+ Kd3 6. 0-0-0+ Td2#
play all play one stop play next play all
http://matplus.net/start.php?px=1600576227&app=forum&act=posts&fid=xshows&tid=2343
James Malcom: As far as I know, this is the first presentation in a selfmate. Of course it can be argued that a Belen only constitutes White castling with mate, but as far as I see it as long as the BK's journey is done and the last move is White's castling, it is a Belen. haven't seen any opposition to this as I have seen. (2020-09-21)
more ...
comment
Keywords: Belen Theme, Checking key, Castling
Genre: s#
Computer test: Gustav 4.1d, Brute Force
FEN: 8/8/1Q6/1R6/1p3N2/bp6/br3PP1/RNk1K3
Input: James Malcom, 2020-09-21
Last update: Alfred Pfeiffer, 2020-09-22 more...
17 - P1380126
James Malcom
(10) MatPlus.net Forum 31/8/2019
P1380126
(7+4) C+
s#3
1. Lc2+! Kxc2 2. Dd3+ Kxd3 3. 0-0-0+ Sd2#
play all play one stop play next play all
http://matplus.net/start.php?px=1600576227&app=forum&act=posts&fid=xshows&tid=2343
more ...
comment
Keywords: Belen Theme, Checking key, Castling
Genre: s#
Computer test: Gustav 4.1d, Brute Force
FEN: 8/8/3QR3/2r5/1pn5/B7/1P6/RBk1K3
Input: James Malcom, 2020-09-21
Last update: Alfred Pfeiffer, 2020-09-22 more...
18 - P1380128
James Malcom
(34) MatPlus.net Forum 18/9/2019
P1380128
(12+7) C+
#5
1. Sbc3!+ Kc2 2. cxd8=S b5 3. cxb6ep Txe6+ 4. Sxe6 Kd3 5. 0-0-0#
play all play one stop play next play all
http://matplus.net/start.php?px=1600656376&app=forum&act=posts&tid=2343&fid=xshows&page=1

http://www.berlinthema.de/Auswahl_PH.pdf-"Wenn man eine Unterverwandlung haben will, ist die Springerumwandlung in der Regel am einfachsten zu erzeugen, wegen der unterschiedlichen Gangart des Springers. Die (H48b) mag als Erstdarstellung ihre Berechtigung haben, doch daß Schwarz statt b7-b5 auch b7-b6 spielen kann, entwertet m.E. den e.p.-Schlag weitgehend. Zudem wirkt angesichts des ungedeckten Satzschachs das erste Zugpaar künstlich aufgesetzt."
James Malcom: This is the first Valladao-Belen with an underpromotion. However, it is damaged by the common "short" ep and a dualistic move order. (2020-09-21)
comment
Keywords: Belen Theme, Valladao Task, Checking key, under-promotion (S), En passant, Castling as mating move
Genre: n#
FEN: 3b4/1pPPr1p1/4P1P1/p1P5/N1p5/P7/P4P2/RNk1K3
Reprints: H48b Der Reiz des Ungewöhnlichen
Input: James Malcom, 2020-09-21
Last update: Alfred Pfeiffer, 2020-09-22 more...
19 - P1380129
Zalmen Kornin
harmonie 2006
P1380129
(4+3) C+
h#2*
* 1. ... 0-0-0#
1. Kc2! Sb1 2. Kc1 Sa3#
play all play one stop play next play all
more ...
comment
Keywords: Belen Theme (Anti-), Castling as mating move (Satz)
Genre: h#
Computer test: Popeye 4.83
FEN: 8/8/8/8/N1p5/2Nkp3/8/R3K3
Reprints: chessproblem.net 25/2007
(15) MatPlus.net Forum 22/9/2019
Input: James Malcom, 2020-09-21
Last update: Alfred Pfeiffer, 2020-09-22 more...
20 - P1380136
James Malcom
(3) MatPlus.net Forum 20/9/2019
P1380136
(9+4) C+
#3
1. Sg4! Kc2 2. Se5 Kc1 3. Sa3#
play all play one stop play next play all
http://matplus.net/start.php?px=1600576227&app=forum&act=posts&fid=gen&tid=2356
more ...
comment
Keywords: Belen Theme (Anti-)
Genre: 3#
Computer test: Popeye 4.61
FEN: 8/8/8/8/1p1Bp3/1P1kPp2/P4P1N/RN2K3
Input: James Malcom, 2020-09-21
Last update: James Malcom, 2020-09-21 more...
21 - P1380143
Peter Hoffmann
H48c Der Reiz des Ungewöhnlichen 9/2019
P1380143
(14+9) C+
#5
1. Sxc3+! Kc2 2. b8=T! f5 3. gxf6ep Lb5 4. Txb5 Kd3 5. 0-0-0#
play all play one stop play next play all
See the improved P1380148

http://www.berlinthema.de/Auswahl_PH.pdf-"In der einschlägigen Diskussion im „MatPlus Forum“ schälte sich heraus, daß Darstellungen mit Turm- oder Läuferumwandlung noch nicht existier(t)en, und dies rief P.H. auf den Plan, der ja ausdrücklich unerforschtes Terrain sucht.
In seinem Stück ist die Unterverwandlung in einen Turm im zweiten Zug logisch begründet – was auch hier das erste Zugpaar aufgesetzt wirken läßt. Mir scheint, daß das Belén-Motiv eher eine hinderliche Vorgabe ist ... 51
(Die Zweckreinheit der schwarzen Reihenfolge-Auswahl, welche die Damenumwandlung
widerlegt, soll hier nicht näher untersucht wurden. Unseres Erachtens ist sie zweckrein, falls man bereit ist, den Austausch der Möglichkeit 5. L:e4# durch die Möglichkeit 5. 0-0-0# als bloße Kompensation zu sehen.)"

http://matplus.net/start.php?px=1570441154&app=forum&act=posts&fid=gen&tid=2361&pid=17978#n17978

Post #1-"A wonderfull surprise! PH presented today a brand new Valladao-Belen, its already published in Erik Zierke's online book in PDF on Hoffmann's works:

http://www.berlinthema.de/AUSWAHL_PH.pdf

page 181, with full solution and comments. In page 180 are also presented, and commented, the known examples of Valladao-Belen (Just two so far, one of them evolved online recently here in MP):

http://matplus.net/start.php?px=1569833313&app=forum&act=posts&fid=xshows&tid=2343&pid=17926#n17926

After a promotion to Queen, and a promotion to Knight, now we have a promotion to Rook.

****** Peter, thanks for Your interest in the Valladão-Belén!! :"

Post 7-"In his excellent # 5, Peter Hoffmann introduces important novelties in the VB field: The promotion move act in three different levels of significance (control of b3, of b5 avoiding to affect d3, and - not least- create a threat of mate in two in e4, allowing a consistent en passant part in real play) : 2.b8 = R is the most impressive single movement in the whole VB's history!

He refers to the Belén as a "motif". In the old Rebnora forum discussions Frank Richter alluded to an "ornamental effect". For Erik Zierke, the Belén condition arrive to become an obstacle ('Hindernis') for the more satisfactory expression in the Valladão field (in the same book we find others of Peter Hoffmann's creations in this field)."
James Malcom: The first Valladao-Belen with a rook promotion. (2020-09-22)
more ...
comment
Keywords: Belen Theme, Valladao Task, Capture key, Checking key, under-promotion (T), En passant, Castling as mating move
Genre: n#
FEN: B3b3/1P3pPQ/4p3/3pP1P1/3Pn3/BPp2p2/pP3P2/RNk1K3
Reprints: (1) MatPlus.net Forum 30/9/2019
Input: James Malcom, 2020-09-22
Last update: Alfred Pfeiffer, 2020-09-22 more...
22 - P1380144
James Malcom
Zalmen Kornin

chessproblem.net 10/8/2019
P1380144
(12+9) C+
#5
1. Sc3+! Kc2 2. h8=L! e5 3. fxe6ep cxd4 4. Lxd4 Kd3 5. 0-0-0#
play all play one stop play next play all
https://www.chessproblem.net/viewtopic.php?f=7&t=1078&p=2344&hilit=belen#p2344

"Yes, a Valladao-Belen with a Bishop promotion, and the first to ever appear before the public !"

http://www.berlinthema.de/Auswahl_PH.pdf-"P.H.s (H48c) löste eine verstärkte Suche nach einer Darstellung mit der nun einzig noch feh- lenden Läuferumwandlung aus, und formell ist die (H48e) die Erstdarstellung. Allerdings sehen wir hier dieselbe gravierende thematische Schwäche wie in der (H48b), daß der Doppelschritt vor dem e.p.-Schlag nicht exklusiv ist und Schwarz ebenso den Einzelschritt spielen könnte – wodurch es zum gleichen Spiel kommt nur ohne den thematisch unabdingba- ren e.p.-Schlag."

http://matplus.net/start.php?px=1600576227&app=forum&act=posts&fid=xshown&tid=2367-"****...and the solution now is complete. Yes, You knew already, I'm sure: "habemus episcopus" - after Q, N and R, a promotion to Bishop in a published Valladao-Belen!"
James Malcom: The first Valladao-Belen with a bishop promotion. (2020-09-22)
comment
Keywords: Belen Theme, Valladao Task, Checking key, under-promotion (L), En passant, Castling as mating move
Genre: n#
FEN: 8/4p2P/3p4/pPpp1P2/B1pP1P2/Br3p2/1P3P2/RNk1K3
Reprints: H48e Der Reiz des Ungewöhnlichen
(1) MatPlus.net Forum Moremovers 10/8/2019
Input: James Malcom, 2020-09-22
Last update: Alfred Pfeiffer, 2020-09-22 more...
23 - P1380320
James Malcom
www.chess.com 9/7/2020
P1380320
(9+9)
#5
1. Kd3! droht 2. Ke4 ... 3. Kf3 ... 4. Lxg2#,Lxg4#
1. ... Sh5 2. Txh5 b5 3. e8=T! b4 4. Te6 Sxe5+,S~ 5. Txe5#,Tx~#
1. ... Se6,Sf5 2. Lxe6,Lxf5 b5 3. e8=L! b4 4. Lh5 Lf6,L~ 5. Lhxg4#
1. ... b5 2. e8=L! Se6,Sf5 3. Lxe6,Lxf5 b4 4. Lh5 Lf6,L~ 5. Lhxg4#
play all play one stop play next play all
https://www.chess.com/forum/view/more-puzzles/a-challenging-mate-in-5-can-you-find-the-first-move?page=1

http://matplus.net/start.php?px=1601166179&app=forum&act=posts&fid=gen&tid=2507
Henrik Juel: Correct key, but damaged by multiple threats and duals, e.g.
1.Kd3 thr. 2.e8=DTLS,Ke4 (2020-09-27)
James Malcom: Typo fixed. And Henrik, the threats are not the point here. The point here is how the different play of the Black knight changes White's promotions. (2020-09-27)
A.Buchanan: It's a beautiful idea, still looking for its rendering though as the many duals and the obstreperous wL are quite distracting (2020-09-28)
James Malcom: There aren't any duals in full-length variations, though. The extra bishop is indeed annoying, but unfixable so far. (2020-09-28)
A.Buchanan: There are still some trivial duals in the mating move, but yes. This problem is trying to ignore threats: you can see that the computer solution. The solution is much more coherent with "nosh noth" switched on. So when are the cases, Henrik, when you switch those options on? It would be event better if one was able to switch threats on for the 4th move. This underscores that there should be a Popeye option for any white move "noth" is self-selecting, depending upon the number of variations. (2020-09-29)
Henrik Juel: Andrew, I use the Popeye option 'nosh' when the output without them is overwhelmingly large
The 'not' option is tricky, and usually expands the output; in some cases it shows apparent duals that are not real ones, when you apply the rule that dualistic play should be ignored, when it appears after black moves that do not prevent the threat
In the case of multiple threats things get messy, like in this problem, as I recall (2020-09-29)
more ...
comment
Keywords: under-promotion (T, L), Changed mates, Non-standard material (L)
Genre: n#
FEN: 2B4R/4P1n1/1p6/4P3/6nb/1P2p2k/2K1Pprp/5B1N
Reprints: MatPlus.net Forum 10/7/2020
Input: James Malcom, 2020-09-27
Last update: James Malcom, 2020-09-29 more...
24 - P1380368
James Malcom
MatPlus.net Forum 22/9/2020
Gewidmet Zalmen Kornin & Peter Hoffmann
P1380368
(14+9) C+
#7
1. Sc3+! Kc2 2. exd4 hxg1=D+,T+ 3. Txg1 Lxh5 4. g4 fxg3ep 5. Txg3 Lg4 6. Txg4 Kd3 7. 0-0-0#
play all play one stop play next play all
http://matplus.net/start.php?px=1601242024&app=forum&act=posts&fid=gen&tid=2488

http://www.berlinthema.de/Auswahl_PH.pdf-"J.M. arbeitete weiter am Valladao-Belén und konnte ihn schließlich gemischtfarbig zeigen! Den „Umwandlungsdual“ halten wir für irrelevant, da ohne Pattmotiv die Turmumwandlung kein eigenständiger Zug ist. Und wir anerkennen durchaus die Pionierleistung! Andererseits ist ein ungedecktes Satzmatt eine sehr häßliche Konstruktionserleichterung."
more ...
comment
Keywords: Belen Theme, Valladao Task, Checking key, En passant, Promotion, under-promotion (t), Castling as mating move
Genre: n#
Computer test: Popeye 4.61
FEN: 8/5B2/6P1/3P3Q/2pq1pb1/Bp2Pp2/pP3PPp/RNk1K1NR
Reprints: H48i Der Reiz des Ungewöhnlichen 9/2020
Input: James Malcom, 2020-09-27
Last update: James Malcom, 2021-12-26 more...
25 - P1380439
James Malcom
MatPlus.net Forum 23/09/2020
P1380439
(13+1) C+
#4
1. ... Kxc2 2. Sd2! Kxd3 3. Sc4 Kc2 4. Se3+ Kd3 5. Td1#
play all play one stop play next play all
See also P1380440
Henrik Juel: Apparently there is a #3
1.c4? Kxc2 2.Sc3 Kxd3 3.0-0-0?
But two facts prevent this try
1. Black has no last move, so he has the move
2. wKe1 must have moved, so White cannot castle
The solution is
0... Kxc2 1.Sd2 Kxd3 2.Sc4 Kc2 3.Se3+ Kd3 4.Td1#
C+ Popeye 4.61 (2020-09-29)
comment
Keywords: Rex solus (s), Belen Theme (Anti-), Cant Castler, No legal last move for Black, Capture key
Genre: n#, Retro
Computer test: Popeye 4.61
FEN: 8/8/8/8/8/BPPP1P2/PPB2P2/RNk1KR2
Input: A.Buchanan, 2020-09-29
Last update: Alfred Pfeiffer, 2020-10-08 more...
26 - P1380440
James Malcom
Andrew Buchanan

MatPlus.net Forum 23/09/2020
P1380440
(10+1) C+
#4
A retro try is:
1. c4? Kxd3 2. Sc3 Kd4 3. Ld6 Kd3 4. 0-0-0#?
2. ... Kc2 3. c5 Kd3 4. 0-0-0#?
but wK has moved, so neither line works.

1. f3! Kxd3 2. Kf2 Kc2 3. Se3+ Kd3 4. Td1#

R: 1. Kc1xLc2 Lb1xTc2,Lb1xSc2
So OK for WTM
play all play one stop play next play all
Henrik Juel: Compared to James's P1380439:
1. Last move could be Kc1xLc2, so White has the move
2. White may not castle, so
1.c4? Kxd3 2.Sc3 Kd4 3.Ld6 Kd3 4.0-0-0, 2... Kc2 3.c5 Kd3 4.0-0-0 is a try
The solution is
1.f3 Kxd3 2.Kf2 Kd2 3.Se3 Kd3 4.Td1#
2... Kc2 3.Se3+ Kd3,Kd2 4.Td1#
C+ Popeye 4.61
Very nice, James and Andrew (2020-09-29)
A.Buchanan: Thanks Henrik - Belen precondition of bKc1 was satisfied 1.0 move ago. From that position there is a sound #5 but position is clunky and not Meredith.
You didn’t fall into the trap of thinking Black has no last move: there is a dualized solution with BTM waiting for you if you did. (2020-09-30)
James Malcom: Haha, yeah. I fell for Andrew's trap, hook, line, and sinker! :-) (2020-09-30)
comment
Keywords: Rex solus, Belen Theme (Normal & Anti-), Cant Castler
Genre: n#, Retro
FEN: 8/8/8/8/8/BPPP4/PPk2P2/R2NK3
Input: A.Buchanan, 2020-09-29
Last update: A.Buchanan, 2021-07-17 more...
27 - P1380551
James Malcom
MatPlus.net Forum 19/2/2020
"The King's Dilemma"
P1380551
(7+8)
Gewinn
1. 0-0-0xd1+! g1=D 2. Txg1+ Kxg1 3. a6 f2 4. Ld4 Lb8 5. b5
play all play one stop play next play all
http://matplus.net/start.php?px=1601649783&app=forum&act=posts&fid=xshowe&tid=2441
James Malcom: P1380523 is the only predecessor I know with the idea of castling with capture. (2020-10-02)
comment
Keywords: Joke, Castling key
Genre: Studies
FEN: 8/7B/8/P7/1Pp5/3p1p1n/1B1P2pb/R2nK2k
Input: James Malcom, 2020-10-02
Last update: James Malcom, 2021-08-04 more...
28 - P1380852
James Malcom
Andrew Buchanan

MatPlus.net Forum 12/10/2020
after Josef Cumpe
P1380852
(1+7)
Last two moves?
(-:
R: 1. 0-0-0+ a7-a8=sT
play all play one stop play next play all
See P1234039 and P1375777
The joke here is that pawns may promote to enemy officers (but not to pawns or kings)
Henrik Juel: R: 1... 0-0-0+ 2.a7-a8=sT! (2020-10-12)
A.Buchanan: Maybe this is a moderate joke where we allow promotion to Bl officers, while son-of-P1375777 can be the extreme joke where promotion to any Bl unit is allowed (i.e. pawn & king too), including in the history of the game. What would Josef Cumpe think? :-) He and I are both dressed as clerics in out chesscomposers' blogspot pics: http://chesscomposers.blogspot.com/2012/08/august-16th.html. Perhaps he was a real one though? (2020-10-13)
comment
Keywords: Last Moves?, Joke promotion (t), Rex solus, Type C, Castling in the retro play, Joke, Promotion in the retro play (t), Castling (sg)
Genre: Retro
FEN: 2kr2K1/1p1p1npr/8/8/8/8/8/8
Input: A.Buchanan, 2020-10-12
Last update: A.Buchanan, 2023-08-15 more...
29 - P1380855
James Malcom
MatPlus.net Forum 12/10/2020
P1380855
(14+14) C+
BP in 12.0
1. g3 d6 2. Lg2 Dd7 3. Ld5 Dh3 4. Le6 fxe6 5. a4 Kf7 6. a5 Kg6 7. a6 Kh5 8. axb7 g6 9. bxa8=L Lg7 10. Lg2 Lxb2 11. Sf3 Lg7 12. Lb2 Lb7
play all play one stop play next play all
James Malcom: The theme is that 5 bishops are fianchettoed-one more than normally allowed! (2020-10-13)
Rainer Staudte: Rules allow a 20-bishops-fianchetto. (2020-10-13)
Henrik Juel: Very nice, James
For this short PG any tester will suffice, but if you push this idea further, Natch is much faster than Jacobi (2020-10-13)
A.Buchanan: Can’t a fianchettoed bishop go round to the bank rank and do it again? So even 20 is not a barrier (2020-10-13)
A.Buchanan: Dates in PDB are yyyy-mm-dd or dd/mm/yyyy. Hence I will change publication date from Dec to Oct (2020-10-13)
James Malcom: Right-the date slipped me again!

Andrew, while a bishop can easily be fianchettoed twice+, about the number of bishops doing it, not how many times it is done. I'm sure that an expert could do 6 fianchettoing bishops. (2020-10-13)
A.Buchanan: I am joking James: this is cool already (2020-10-13)
comment
Keywords: Promotion (L), Phoenix, Impostor (L), Unique Proof Game
Genre: Retro
Computer test: Jacobi v0.7.5
FEN: 1n4nr/pbp1p1bp/3pp1p1/7k/8/5NPq/1BPPPPBP/RN1QK2R
Input: James Malcom, 2020-10-13
Last update: A.Buchanan, 2021-04-06 more...
30 - P1380896
Andrew Buchanan
MatPlus.net Forum 12/10/2020
P1380896
(13+13) C+
PG in 6.5
(-:
1. b4 g5 2. b5 g4 3. b6 g3 4. bxa7 gxh2 5. axb8=sS! hxg1=wT! 6. Txh7 Txh7 7. Th1
play all play one stop play next play all
The joke here is that pawns may promote to foreign units.
Henrik Juel: The testers probably do not work here, but this seems unique
1.b4 g5 .. 4.bxa7 gxh2 5.axb8=sS hxg1=wT 6.Txh7 Txh7 7.Th1 (2020-10-14)
A.Buchanan: According to Joost De Heer, WinChloe has a category “promotions adverses”, and under this, the problem is C+. Looking now for a full Homebase without utilising promotion to enemy pawn, which makes it too easy (2020-10-15)
comment
Keywords: Unique Proof Game, Joke, Joke promotion (sT), Homebase (w), Phoenix (s), Prenix (T), Impostor (sT)
Genre: Retro, Fairies
Computer test: C+ WinChloe
FEN: rnbqkbn1/1ppppp1r/8/8/8/8/P1PPPPP1/RNBQKB1R
Input: A.Buchanan, 2020-10-14
Last update: A.Buchanan, 2022-09-18 more...
31 - P1381266
James Malcom
(2) MatPlus.net Forum 27/9/2019
P1381266
(6+7) C+
#7
1. Kc1! d6 2. h8=S! gxh6 3. Sg6 h5 4. Sf4 h4 5. Sxd3 h3 6. Se1 h2 7. Sc2#
play all play one stop play next play all
https://www.matplus.net/start.php?px=1603494562&app=forum&act=posts&fid=xshown&tid=2346
James Malcom: This composition is one of my personal favorites amongst mine. It was inspired be Krabbe's Journal #89, which touches on the so called theme of "remote knight promotion." The point of this is to show the aximum diaganol distance with kings and pawns only.

A Meredith rendering is still pending for any geniuses out there. (2020-10-24)
more ...
comment
Keywords: Stalemate avoidance, Kindergarten Problem, under-promotion (S)
Genre: n#
Computer test: Gustav 4.1d, Brute Force
FEN: 8/3p2pP/7P/p2P4/p7/P2p4/p2P4/k2K4
Input: James Malcom, 2020-10-24
Last update: Alfred Pfeiffer, 2020-10-26 more...
32 - P1381285
Andrew Buchanan
James Malcom

MatPlus.net Forum 25/10/2020
P1381285
(5+7) C+
#3
Bosma
1. Tf5+! Sxf5+ 2. Se4+! Sxe4 3. De6#
play all play one stop play next play all
James Malcom: I've added in the solution now. (2020-11-02)
Henrik Juel: Thanks, James
I cannot test the problem, but it seems OK (2020-11-02)
A.Buchanan: Thanks Henrik: it's C+ according to WinChloe (2020-11-03)
comment
Keywords: Aristocrat, Bosma
Genre: 3#, Fairies
Computer test: C+ WinChloe v3.51
FEN: 3r2R1/3Q4/3K1k2/2n1R3/1b6/6n1/3N3q/3r4
Input: A.Buchanan, 2020-10-25
Last update: A.Buchanan, 2020-11-03 more...
33 - P1381345
James Malcom
(36) MatPlus.net Forum 14/10/2020
P1381345
(13+11) C+
BP in 9.5
(-:
1. f4 h5 2. f5 h4 3. f6 h3 4. fxe7 hxg2 5. exf8=B gxh1=T 6. Lg2 Ke7 7. Lxb7 Ke6 8. Lxa8 Se7 9. Lb7 Txf8 10. Lxc8
play all play one stop play next play all
http://matplus.net/start.php?px=1603899391&app=forum&act=posts&tid=2475&fid=gen&page=1
James Malcom: The point of this PG was to make a true Belfort, after the lone bishop in P1379376 was pointed out to not be a true Belfort. (2020-10-28)
A.Buchanan: Belfort is not in the Encyclopedia! (2020-10-30)
more ...
comment
Keywords: Schnoebelen Theme (B), Dummy Pawn, Golden Age (Dummy Pawn), Belfort (Lt), Prenix (t), Prentos Theme (B), Ceriani-Frolkin Theme (B), Unique Proof Game
Genre: Retro
Computer test: Jacobi v.0.7.5
FEN: 1nBq1r2/p1ppnpp1/4k3/8/8/8/PPPPP2P/RNBQK1Nr
Input: James Malcom, 2020-10-28
Last update: A.Buchanan, 2023-08-04 more...
34 - P1381369
Andrew Buchanan
MatPlus.net Forum 28/10/2020
P1381369
(14+14) C+
KBP in 4.0
1. e3 a6 2. Lxa6 bxa6 3. De2 Lb7 4. Dxa6 Lxa6
play all play one stop play next play all
shortest PG with 4 units captured on 1 square
Henrik Juel: 1.Be2-e3 Ba7-a6 2.Lf1xa6 Bb7xa6 3.Dd1-e2 Lc8-b7 4.De2xa6 Lb7xa6
Very easy and C+ by Natch 3.1
Nice tempo move 3... Lb7 (2020-10-29)
A.Buchanan: Thanks - tempo is to force unique order on Wh moves (2020-10-30)
comment
Keywords: Unique Proof Game, Tempo Move, Task (Construction) (4), Superseded by (P1381879), x pieces capture on one square (4)
Genre: Retro
Computer test: C+ by Natch 3.1
FEN: rn1qkbnr/2pppppp/b7/8/8/4P3/PPPP1PPP/RNB1K1NR
Input: A.Buchanan, 2020-10-29
Last update: A.Buchanan, 2021-04-18 more...
35 - P1381879
Andrew Buchanan
MatPlus.net Forum 3/11/2020
P1381879
(13+13) C+
BP in 7.0
1. e4 a6 2. Lxa6 bxa6 3. De2 Lb7 4. Dxa6 Sxa6 5. b4 Db8 6. b5 Da7 7. bxa6 Dxa6
play all play one stop play next play all
Inspired by P1381620

See also P1381369
Henrik Juel: C+ Natch 3.1
1.Be2-e4 Ba7-a6 2.Lf1xa6 Bb7xa6 3.Dd1-e2 Lc8-b7
4.De2xa6 Sb8xa6 5.Bb2-b4 Dd8-b8 6.Bb4-b5 Db8-a7
7.Bb5xa6 Da7xa6
Six captures on a6 (2020-11-14)
comment
Keywords: Unique Proof Game, x pieces capture on one square (6), Construction task
Genre: Retro
Computer test: Natch 3.1
FEN: r3kbnr/1bpppppp/q7/8/4P3/8/P1PP1PPP/RNB1K1NR
Input: A.Buchanan, 2020-11-14
Last update: James Malcom, 2021-02-01 more...
36 - P1382303
James Malcom
Jacques Rotenberg

(10) MatPlus.net Forum 22/11/2020
P1382303
(8+5) C+
#2
1. Tb2+? Ka3!

1. Lf3! ... 2. Ld1#
play all play one stop play next play all
Inspired by P1182074

White releases stalemate as a #2, giving Black 20(!) moves. First record in a new task. See:
http://matplus.net/start.php?px=1606065655&app=forum&act=posts&fid=gen&tid=2586&pid=20040#n20040
Henrik Juel: No record, P1182074 is far better in terms of giving Black moves, 32
But this problem also a #2 (2020-11-22)
A.Buchanan: First record in a new task (2020-11-22)
James Malcom: Henrik, you misunderstood! The task is different from the 32! This is about Black release in the #2 form, not releae in the fairy form. (2020-11-22)
comment
Keywords: Stalemate dissolution
Genre: 2#
Computer test: Popeye 4.85
FEN: 8/8/NN1p4/1p1B4/1Pr5/1kb4R/3R4/1KB5
Input: James Malcom, 2020-11-22
Last update: James Malcom, 2021-06-22 more...
37 - P1382697
Guus Rol
MatPlus.net Forum 29/11/2020
P1382697
(4+7)
What's the best White can do?
b) sTg1
a) No permitted moves
b) 1. fxg6ep+ Kxg6 2. Dg5#
play all play one stop play next play all
The end position is dead if Black's last move was R: 1. ... g6-g5+ (stalemate is inevitable) but not if it was R: 1. ... g7-g5+ which allows for e.p. Looking at the position prior to the last move:
a) the position with sB on g6 is not dead regardless since the sD can intervene instead of the bP move. This makes the e.p. invalid which would force 1. Dxg5+ Txg5=
b) the position with sB on g6 is already dead so the sB must have come from g7 allowing white to win by 1. fxg6ep+
AB: So what happens in a)? We can't know from the position, even with DP. If White can ep, he wins; if he can't the position is newly dead but still legal (as the alternative last move Qe3 would have kept the game alive). The ep convention specifically resolves the permissibility of the ep itself, but it's too narrow to claim (as at one point I did) that it fails to resolve the permissibility of the contingent Qg5+. So there are no permitted moves.

Suggested position evaluation in orthodox problem chess (OPC) (sketch):
1) What legal moves are there? ("legal" as per FIDE)
2) If 0 legal moves, then is there check? Yes/No => Mate/Pat.
Otherwise there is at least 1 legal move.
If an ep is legal set flag
3) Has this position occurred before? Yes/No => 3Rep/continue.
Is this RETRO? Yes/No => continue/play any legal move.
4) 50.0 moves since last capture or pawn move? Yes/No => 50M/continue
5) Check the child nodes recursively until find which mate. Success/Fail? => play any legal move)/Dead
Henrik Juel: 1.Dxg5+ Txg5= seems to secure half a point in both twins
So there is probably some DP trickery, which Andrew will explain soon... (2020-12-03)
Yoav Ben-Zvi: The end position is dead if Black's last move was -1...bPg6-g5 (Stalemate is inevitable) but not if it was -1...bPg7-g5 which allows for e.p. Looking at the position prior to the last move: in a) it is not dead regardless since the bQ can intervene instead of the bP move (this makes the e.p. invalid forcing 1.wQxg5) but in b) the position with bP on g6 is already dead so the bP must have come from g7 allowing white to win by 1.wPf5xg6 e.p. (2020-12-04)
A.Buchanan: Suggested principle for orthodox problem chess (OPC): playing forwards chess should always be on the basis (at least conceptually) of knowing the full gamestate (castling, e.p.). One can then run the forwards chess for each combination. Call this a "scenario" Some combinations can be rejected as illegal, and we can then hand over to the castling/ep conventions to clear things up.
In a), this results in game over. This makes sense, because under DP the drawing 1.Qg5+ is only playable if the living 1.fxg6ep+ is also playable. So the ep convention nixes both.
And how does the game end exactly? The same thing can happen in a simpler position: 8/k7/2p5/KpP5/1P6/8/8/8 WTM. There are two retro-possibilities, one is pat and the other keeps on going. It's nothing to do with DP rule.
Under RS: The ep convention ends the game, but we can't assume that the history of the game was not the double pawn move! We are just not *permitted* to make this move. We have "draw by ep convention".
Under PRA: our solution comprises one twin, and in that twin, we can assume that ep is actually illegal (or it should be if the conventions were worded properly!) and the position is pat.
The goal here is to codify OPC properly so that it can serve as foundation for retro fairies.
OPC allows for the variations in the castling/ep conventions & protocols. It merely hands off the results of each gamestate scenario. (2022-01-19)
more ...
comment
Keywords: En passant, Forsberg Twins, Dead Position
Genre: Retro
FEN: 6r1/5p1p/5P1k/5Pp1/6pK/8/3Q4/6q1
Input: A.Buchanan, 2020-12-03
Last update: A.Buchanan, 2022-01-19 more...
38 - P1382735
James Malcom
MatPlus.net Forum 13/3/2020
P1382735
(5+4) C+
s#5
1. g4! Ka2 2. g5 Ka1 3. g6 Ka2 4. g7 Ka1 5. g8=L, Se2#,Sf3#,Sh3#
play all play one stop play next play all
http://matplus.net/start.php?px=1607098798&app=forum&act=posts&fid=gen&tid=2449
SCHRECKE: C+, Gustav 4.1d, Brute Force (2020-12-04)
comment
Keywords: Excelsior
Genre: s#
FEN: 8/8/8/8/8/8/1PPP2Pp/k1K3nr
Input: James Malcom, 2020-12-04
Last update: Marcin Banaszek, 2020-12-09 more...
39 - P1382737
James Malcom
MatPlus.net Forum 13/3/2020
P1382737
(3+5) C+
s#5
1. a4! Ka1 2. a5 Kb1 3. a6 Ka1 4. a7 Kb1 5. a8=T Se2#,Sf3#,Sh3#
play all play one stop play next play all
http://matplus.net/start.php?px=1607098798&app=forum&act=posts&fid=gen&tid=2449
SCHRECKE: C+, Gustav 4.1d, Brute Force (2020-12-04)
comment
Keywords: Excelsior
Genre: s#
FEN: 8/8/8/8/8/3p4/P2R3p/1k1K2nr
Reprints: Mat Plus 13/3/2020
Input: James Malcom, 2020-12-04
Last update: Marcin Banaszek, 2020-12-09 more...
40 - P1382738
James Malcom
MatPlus.net Forum 13/3/2020
P1382738
(5+2) C+
s#6
1. g4! Kc2 2. g5 Kc1 3. g6 Kc2 4. g7 Kc1 5. g8=D Kc2 6. Dg5 axb2#
play all play one stop play next play all
http://matplus.net/start.php?px=1607098798&app=forum&act=posts&fid=gen&tid=2449
SCHRECKE: C+, Gustav 4.1d, Brute Force (2020-12-04)
comment
Keywords: Excelsior
Genre: s#
FEN: 8/8/8/8/8/p7/PN4P1/K1k1B3
Input: James Malcom, 2020-12-04
Last update: Marcin Banaszek, 2020-12-09 more...
41 - P1382740
James Malcom
MatPlus.net Forum 13/3/2020
P1382740
(5+7) C+
s#5
1. a4! Kh1 2. a5 Kh2 3. a6 Kh1 4. a7 h2 5. a8=S Se8#,Sh5#
4. ... Kh2 5. a8=L Se8#,Sh5#
play all play one stop play next play all
http://matplus.net/start.php?px=1607098798&app=forum&act=posts&fid=gen&tid=2449
Henrik Juel: C+ Popeye 4.61 (2020-12-04)
comment
Keywords: Excelsior
Genre: s#
FEN: 7b/3p2n1/3Pp3/4Kp2/5N2/7p/P3N2k/8
Input: James Malcom, 2020-12-04
Last update: Marcin Banaszek, 2020-12-09 more...
42 - P1382871
Andrew Buchanan
Geoff Foster

2 The Problemist Supplement 169, p. 120, 11/2020
P1382871
(1+4) C+
h#7
Illegal position
1. Sc6 e4 2. Sd8! e5 3. Sf7 e6 4. Kd8 exf7 5. Kc8! f8=D+ 6. Kc7 Df4+ 7. Kd8 Db8#
play all play one stop play next play all
more ...
comment
Keywords: Homebase (2), Illegal position (no wK), Minimal (super), Excelsior
Genre: h#
Computer test: C+ Popeye 4.61
FEN: 1n2k3/3pp3/8/8/8/8/4P3/8
Reprints: chess.stackexchange.com 27/05/2023
MatPlus.net Forum 28/05/2023
Input: A.Buchanan, 2020-12-11
Last update: A.Buchanan, 2023-12-11 more...
43 - P1382970
James Malcom
MatPlus.net Forum 3/3/2019
P1382970
(15+2)
#1 with double check

14 double check mates

http://matplus.net/start.php?px=1607750786&app=forum&act=posts&fid=gen&tid=2281
HBae: 14 Züge wurden schon 1976 dargestellt, siehe P1178762 (2020-12-13)
comment

Genre: Mathematics
FEN: 4Q3/2B1N1B1/3R1R2/1QN1k1NQ/5R2/2K1N1B1/4Q3/4n3
Input: James Malcom, 2020-12-13
Last update: James Malcom, 2021-04-19 more...
44 - P1384294
James Malcom
MatPlus.net Forum 27/12/2020
nach Bosko Miloseski
P1384294
(11+12)
#51
1. ... Td7 2. Lb1! Kd6 3. De5+ Kc6 4. De6+ Td6 5. De8+ Td7 6. Ka2 Kd6 7. De5+ Kc6 8. De6+ Td6 9. De8+ Td7 10. Ka1 Kd6 11. De5+ Kc6 12. De6+ Td6 13. De8+ Td7 14. La2 Kd6 15. De5+ Kc6 16. De6+ Td6 17. De8+ Td7 18. Kb1 Kd6 19. De5+ Kc6 20. De6+ Td6 21. De8+ Td7 22. Kc1 Kd6 23. De5+ Kc6 24. De6+ Td6 25. De8+ Td7 26. Kd1 Kd6 27. De5+ Kc6 28. De6+ Td6 29. De8+ Td7 30. Ke1 Kd6 31. De5+ Kc6 32. De6+ Td6 33. De8+ Td7 34. Kf2 Kd6 35. De5+ Kc6 36. De6+ Td6 37. De8+ Td7 38. Kg3 Kd6 39. De5+ Kc6 40. De6+ Td6 41. De8+ Td7 42. Kh4 Kd6 43. De5+ Kc6 44. De6+ Td6 45. De8+ Td7 46. Kg5 Kd6 47. De5+ Kc6 48. De6+ Td6 49. De8+ Td7 50. Kxf5! Kd6 51. De6#

50. Kf6? Kd6! Drawn by the 50 move rule!
play all play one stop play next play all
White's pre-diagram move couldn't have been a capture, so the 50-move counter has already been set to 1. Thus, White must play 50. Kxf5 in order to reset the counter, or else Black will draw.

See P1372258

http://matplus.net/start.php?px=1609121267&app=forum&act=posts&fid=gen&tid=2590
Henrik Juel: 3 and 5 captures by white and black pawns are obvious, leaving [Ph2,Ph7], so the remaining white capture was hxg (with promotions on g8 and h1) or officerxPh (with promotion on h8) (2022-11-05)
comment
Keywords: 50 move rule
Genre: Retro, n#
FEN: n3Q3/1pp5/brkr4/Bp1p1p2/1P1PpP2/KPp1P3/B1P1P3/8
Input: James Malcom, 2020-12-28
Last update: A.Buchanan, 2022-11-05 more...
45 - P1385595
Andrew Buchanan
James Malcom
Hauke Reddmann
Michel Caillaud

MatPlus.net Forum 06/01/2021
in memory of Conrad Staugaard
P1385595
(14+13)
PG in 10.0
Staugaard castling
b) 1. d4 f5 2. Kd2 f4 3. Kd3 f3 4. Ke4 fxe2 5. Kf5 e1=T 6. De2 g5 7. Dxe7+ Sxe7+ 8. Kf6 Lg7+ 9. Kxg7 Sd5 10. Kxh8 0-0-0-0-0-0#
play all play one stop play next play all
Objective: Staugaard (Pam-Krabbé) castling as mating move.
Henrik Juel: solution
1. Bd2-d4 Bf7-f5 2. Ke1-d2 Bf5-f4 3. Kd2-d3 Bf4-f3
4. Kd3-e4 Bf3xe2 5. Ke4-f5 Be2-e1=T 6. Dd1-e2 Bg7-g5
7. De2xe7 Sg8xe7 8. Kf5-f6 Lf8-g7 9. Kf6xg7 Se7-d5
10. Kg7xh8 0-0-0-0-0-0#
First 9.5 moves are C+ Euclide 1.01
On behalf of the danish inventor of the looong castling, I thank for the dedication (2021-01-21)
James Malcom: After the 12.5 Andrew and I made, this turns out the fastest possible. 9.0 if you go non-unique. (2021-01-21)
A.Buchanan: Welcome, Henrik. Any idea what his initial "C." stands for? I couldn't find it online. (2021-01-22)
Henrik Juel: Unfortunately not, Andrew
In those days the first name was almost always abbreviated to an initial
Christian was a very common first name, but this was usually abbreviated to Chr.
So a wild guess is Carl, but it really could be anything starting with C
In a Skakbladet issue he is referred to as Direktør Staugaard, but this just means that he was in charge of a company (2021-01-22)
A.Buchanan: I have posted an English definition of the keyword. Please check if it suits. (2021-01-22)
Henrik Juel: Searching for direktør staugaard, randers (a danish city) yields
Conrad Staugaard (1852-1922)
so this is my best bet
Conrad Staugaard headed a bank in Randers, founded by him in 1891, but the CV in
http://historiskranders.dk/randers-biografier/
does not mention anything about playing chess or chess problems
Chess playing was very common in the middle class, so the biographer may not have found it worth mentioning (2021-01-22)
Henrik Juel: Your keyword definition seems fine,
except for the spelling of showcase... (2021-01-22)
A.Buchanan: Haha bingo: "Staugaard was a well-known and excellent chess-player, one of the many traits he had in common with Lewis Carroll". MMA SAM - Tidsskrift.dk. Googling for "Conrad Staugaard skak" brings up the pdf for Rama Sama. Please tell us what you make of it, Henrik :) In the mean time, I have updated the author info for him (2021-01-22)
Henrik Juel: Very good, Andrew
Ah, the joys of Google...
In the danish text there is not only your citation on chess, but also one on chess problems
There are also examples of Conrad's excentric behaviour, in line with him inventing the looong castling
That C. Staugaard might be Conrad's younger brother Carl (who surely also knew about chess) is ruled out by the fact that Carl emigrated to South America in 1901, because he experienced disappointments in his love live... (2021-01-22)
A.Buchanan: Yes it said he had lots of amazing concepts. The idea about the banner for his nursemaid to take his children for walks without getting her arms stretched is very funny. This is our man. He also seems to have been a good man, and an effective businessman. And loved enough by his friends for a 120 page book to have been commissioned in his memory. He is reminiscent of other children’s authors like Edward Lear, Dr Seuss, Heinrich Hoffmann... I’m so happy that this problem has brought him back to our awareness (2021-01-23)
comment
Keywords: Unique Proof Game, Staugaard castling, Prenix (t), Promotion (t), Castling as mating move, Economy record
Genre: Retro, Fairies
Computer test: HC+ the last move can only have been 0^6 discovering mate & the first 9.5 moves are C+ Euclide 1.01.
FEN: rnbq3K/ppppr2p/4k3/3n2p1/3P4/8/PPP2PPP/RNB2BNR
Input: A.Buchanan, 2021-01-21
Last update: Rainer Staudte, 2021-05-10 more...
46 - P1385596
Nikola Predrag
MatPlus.net Forum 08/01/2021
P1385596
(14+14)
PG in 7.5
Staugaard castling
b) 1. e4 Sf6 2. Df3 Sh5 3. Df6 exf6 4. e5 Le7 5. exf6 0-0 6. fxe7 Sg3 7. e8=T Sxh1 8. 0-0-0-0-0-0
play all play one stop play next play all
Objective: fastest Staugaard (Pam-Krabbé) + kingside castling.
more ...
comment
Keywords: Unique Proof Game, Staugaard castling, Castling (2), Prenix (T), Promotion (T), Superseded by (P1389375)
Genre: Retro, Fairies
FEN: rnbq1rk1/pppp1ppp/8/8/8/4K3/PPPPRPPP/RNB2BNn
Input: A.Buchanan, 2021-01-21
Last update: Rainer Staudte, 2021-05-10 more...
47 - P1385597
Andrew Buchanan
MatPlus.net Forum 08/01/2021
P1385597
(14+14) C+
PG in 7.5
Staugaard castling
b) 1. e4 d5 2. Ld3 Lf5 3. exf5 Dd6 4. f6 Sd7 5. Lg6 0-0-0 6. fxe7 Dxh2 7. e8=T Dxh1 8. 0-0-0-0-0-0
play all play one stop play next play all
Popeye says there's no orthodox solution in 7.5, so it must be Staugaard. With castling as W8, there Popeye finds a unique solution for the first 7.0. Otherwise we can count both sides' moves, with e2-e4xLf5-f6xBe7-e8=T. If we R: 1. Ld3-g6 Dh7xTh8 2. 0^6, then Popeye says no solution, and there is no alternative White retraction. This is enough for me to say HC+.
Objective: Staugaard (Pam-Krabbé) + queenside castling.
more ...
comment
Keywords: Unique Proof Game, Staugaard castling, Castling (2), Prenix (T), Promotion (T)
Genre: Retro, Fairies
Computer test: HC+ Popeye v4.85 + argument in sol text
FEN: 2kr1bnr/pppn1ppp/6B1/3p4/8/4K3/PPPPRPP1/RNBQ2Nq
Input: A.Buchanan, 2021-01-21
Last update: Rainer Staudte, 2021-05-10 more...
48 - P1385598
Andrew Buchanan
MatPlus.net Forum 10/01/2021
P1385598
(14+14)
PG in 7.5
Staugaard castling
1. d4 e5 2. Lf4 exf4 3. Dd3 f3 4. Dxh7 fxe2 5. f4 g6 6. Kf2 e1=T 7. Dxh8 0-0-0-0-0-0 8. De5#
play all play one stop play next play all
Objective: Staugaard (Pam-Krabbé) king is mated.
Henrik Juel: The first 6.5 moves are C+ Euclide 1.01 (2021-05-08)
A.Buchanan: Thanks Henrik. In the advance of an engine supporting Staugaard, here is my purely HC+ proof of soundness. No orthodox solution so 6 Bl moves needed to Staugaard. Other Bl move was g7-g6 or h7xg6. bRh8 & other bPg/bPh never moved - captured by Wh raider(s). Only piece that could have captured wPe was bPe, so it captured twice, other prey being wB, which thus moved once, and could not have been the raider. 6 Wh moves now countable without raiding, so wQ raided, and took 4 moves. All Wh moves now accounted for, so bPe7-e5xf4-f3xe2-e1=T. wQ could only have exited on d file, as diagonal d1-h5 open too late. Thus wQ-d3xh7xh8-e5#. All moves are known, and jigsaw of them moves is unique, ensuring each side can always move. (2021-05-08)
A.Buchanan: I forgot to say that I think my manual proof, while watertight, is too complex to make the status of this problem HC+. I think HC+ is for where the H part is self-evident. (2021-05-08)
more ...
comment
Keywords: Unique Proof Game, Staugaard castling, Prenix (t), Promotion (t), Castling
Genre: Retro, Fairies
FEN: rnbq1bn1/pppprp2/4k1p1/4Q3/3P4/5P2/PPP2KPP/RN3BNR
Input: A.Buchanan, 2021-01-21
Last update: Rainer Staudte, 2021-05-10 more...
49 - P1385599
Michel Caillaud
MatPlus.net Forum 12/01/2021
P1385599
(15+14)
PG in 8.0
Staugaard castling
b) 1. e4 d5 2. e5 Dd6 3. exd6 Kd7 4. dxe7 Kc6 5. e8=T Kb6 6. 0-0-0-0-0-0 Lg4 7. Kf4 Lxe2 8. Kg3 Lc4
play all play one stop play next play all
Objective: Objective: Staugaard (Pam-Krabbé) rook is captured.
Henrik Juel: solution
1.e4 d5 2.e5 Dd6 3.exd6 Kd7 4.dxe7 Kc6 5.e8=T Kb6 6.0-0-0-0-0-0 Lg4 7.Kf4 Lxe2 8.Kg3 Lc4
Hidden castling (2021-01-21)
A.Buchanan: Thematic Ceriani-Frolkin seems a great way to conceal P-K castling! But normally wK returns to e1 in hidden castling. Absence of P-K in engine makes it harder to verify soundness of implausible moves like that. (2021-01-22)
comment
Keywords: Unique Proof Game, Staugaard castling, Ceriani-Frolkin Theme (T), Castling Paradox (hidden P-K), Promotion (T), Prentos Theme (T)
Genre: Retro, Fairies
FEN: rn3bnr/ppp2ppp/1k6/3p4/2b5/6K1/PPPP1PPP/RNBQ1BNR
Input: A.Buchanan, 2021-01-21
Last update: Rainer Staudte, 2021-05-10 more...
50 - P1385600
Michel Caillaud
MatPlus.net Forum 14/01/2021
P1385600
(14+14)
PG in 12.5
Staugaard castling
b) 1. e4 h5 2. e5 h4 3. Dh5 h3 4. Le2 hxg2 5. h4 Th6 6. Th3 Tb6 7. Ta3 d6 8. Ta6 Kd7 9. Lg4+ f5 10. exf6ep+ Kc6 11. fxe7 bxa6 12. e8=T Kb7 13. 0-0-0-0-0-0
play all play one stop play next play all
Objective: Staugaard (Pam-Krabbé) Valladao.
more ...
comment
Keywords: Unique Proof Game, Staugaard castling, Valladao Task, En passant, Castling, Prenix (T), Promotion (t)
Genre: Retro, Fairies
FEN: rnbq1bn1/pkp3p1/pr1p4/7Q/6BP/4K3/PPPPRPp1/RNB3N1
Input: A.Buchanan, 2021-01-21
Last update: Rainer Staudte, 2021-05-10 more...
51 - P1385601
Andrew Buchanan
MatPlus.net Forum 16/01/2021
to Joost de Heer
P1385601
(12+15)
PG in 11.5
b) Is the position before the last black move a sound proof game in 10.5?
Staugaard castling
a) 1. e3 h6 2. Ld3 Th7 3. Lxh7 e6 4. Lf5 exf5 5. Sf3 f4 6. 0-0 fxe3 7. Se1 exd2 8. Df3 dxe1=T 9. Le3 b6 10. Sd2 b5 11. Lb6 0-0-0-0-0-0 12. Tfb1
b) No: 1. e3 h6 2. Ld3 Th7 3. Lxh7 e6 4. Lf5 exf5 5. Sf3 f4 6. 0-0 fxe3 7. Se1 exd2 8. Df3 and now d1=T 9. Le3 Txe1/b5/b5 10. Sd2/Sd2/Lb6 b5/Txe1/Txe1 11. Lb6/Lb6/Sd2 have no P-K castling rights.
play all play one stop play next play all
Objective: Play of Staugaard (Pam-Krabbé) castling makes unsound PG sound.
Henrik Juel: I see no castling paradox (2021-01-21)
A.Buchanan: I must complete the stipulation, sry (2021-01-22)
A.Buchanan: Not really paradox in the usual hidden/fake sense. Need a different term for the occasional idea that an earlier point in the proof game is not unique. (2021-01-22)
more ...
comment
Keywords: Unique Proof Game, Staugaard castling, Phoenix (t), Promotion (t), Castling (2)
Genre: Retro, Fairies
FEN: rnbq1bn1/p1pprpp1/1B2k2p/1p6/8/5Q2/PPPN1PPP/RR4K1
Input: A.Buchanan, 2021-01-21
Last update: A.Buchanan, 2021-05-09 more...
52 - P1389077
Adrian Storisteanu
Discord Chess Problems & Studies Server 4/4/2021
2. Platz
CP&S Discord Server Composition Tourney 0 {}
P1389077
(3+2)
Switcheroo # =<1* (-:
(i.e. swap two pieces for mate in one or less)
1. De4# but faster is:
Swap Tc4<->Ba1 and now 1. Ta1->d1, completing 0-0-0#
play all play one stop play next play all
PR Edderiofer wrote: "Another mid-castling position. "=1" here initially suggested to me "in 0 or 1 plies", but of course, 0.5 = 1 too. (Should that be 0.25 if it's in a helpmate? I don't know.)"
Henrik Juel: based on the keywords, probably
switch La1 and Tc4, then 1.Td1#, i.e. complete the castling (2021-04-30)
comment
Keywords: Joke, Aristocrat, Minimal, Miniature, Castling (Complete or retract)
Genre: Retro
FEN: 8/8/8/4Q3/2R5/3k4/8/b1K5
Reprints: MatPlus.net Forum 4/4/2021
Input: A.Buchanan, 2021-04-29
Last update: Alfred Pfeiffer, 2021-07-27 more...
53 - P1389079
Adrian Storisteanu
Discord Chess Problems & Studies Server 4/4/2021
3. Platz
CP&S Discord Server Composition Tourney 0 {}
P1389079
(4+3)
"Better late than never"
h#1 (-:
1. d5 Le4 2. Ld7 exd6ep#
play all play one stop play next play all
PR Edderiofer comment: "As the title of the problem says, better late than never! Black and White have to each play a move in between 1.d5 and exd6e.p.! Luckily, Black is very accommodating, as in the spirit of a helpmate. Yep, that's totally a helpmate in one. :P"
Henrik Juel: maybe something like
1.d5 Le4 2.Ld7 exd6ep# (2021-04-30)
A.Buchanan: I would say that's still h#2 (2021-05-02)
Adrian Storisteanu: All-around cecity... I actually submitted it as "h#1". Please correct. (2021-05-02)
comment
Keywords: Joke, Miniature, En passant (delayed!)
Genre: h#
FEN: 8/3p4/2k5/2P1PB2/1K4b1/8/8/8
Reprints: MatPlus.net Forum 4/4/2021
Input: A.Buchanan, 2021-04-29
Last update: Alfred Pfeiffer, 2021-07-27 more...
54 - P1389081
Per Olin
Discord Chess Problems & Studies Server 4/4/2021
4. Place
CP&S Discord Server Composition Tourney 0 {}
P1389081
(2+3)
Add the Black king to give the shortest possible helpmate
Chess960
1. 0-0-0! Ld3 2. Lb8 La6#
play all play one stop play next play all
Try: +bKd8 and 1. 0-0-0 Ld3 2. Lb8 La6#
sBd5 prevents solutions like:
+Ka8 and 1. Lb8+ Kb6 2. Th8 Le4# or 1. Th8 Le4 2. Lb8 Kb6# making the try unique.

The rules for Chess960 castling says that 'it is recommended that the king be moved outside the playing surface next to his final position, the rook then be moved from its starting position to its final position, and then the king be placed on his final square'.

The bK is added on c9, whereby 1/3 of the castling has been performed (previous square for bK was d8), and remains 2/3 (two thirds) of the castling, which is performed by Rc8 moving to d8 and bK moving to c8. The helpmate is then in 1 5/6 moves (one and five sixths) by starting with finishing the castling.

PR Edderiofer comment: "This is a reprise of the joke from 9th place, but in a much simpler setting. This one arrived ten minutes before the submission period closed, again on the same day when I was already extremely tired, so thankfully I was able to appreciate this one better! Adding a piece outside the board is pretty cool."
Henrik Juel: maybe something like
complete a Chess960 castling ending with Tc8 on b8 and sK on c8, then
1.Ld8 Lf5# (2021-04-30)
comment
Keywords: Joke, Chess960, Castling (Complete or retract), Minimal, Miniature
Genre: h#, Fairies
FEN: 2r5/2b5/2K3B1/3p4/8/8/8/8
Reprints: MatPlus.net Forum 4/4/2021
Input: A.Buchanan, 2021-04-29
Last update: Alfred Pfeiffer, 2021-07-27 more...
55 - P1389082
Dmitri Turevski
Discord Chess Problems & Studies Server 4/4/2021
Motto: "Flipping the bird"
5. Platz
CP&S Discord Server Composition Tourney 0 {}
P1389082
(1+7) C+
h#2.5
Masand
sDL:Adlee
1. ... Kf4 2. Dc4[c7=w]+ Kg3 3. Df1 Kf3#
play all play one stop play next play all
Masand: A piece which directly threatens the opposite King, after it moves, changes the color of the pieces it controls or attacks, except the Kings. Castling may be done with a colour-changed rook in the corner.
Eagle: Moves like a Grasshopper, but deflects 90° either way on passing over the hurdle. The arrival square is adjacent to the hurdle.

PR Edderiofer comment: "The subtle joke here is that the end position is otherwise the same as the start position except with White to move and with the Eagle having changed colours, so this problem is "flipping the bird"."
Henrik Juel: Popeye 4.61 found no joke, but a neat triangle by wK
1...Kf3-f4 2.Qf1-c4[wEAc7]+ Kf4-g3 3.Qc4-f1 Kg3-f3# (2021-04-30)
A.Buchanan: Sublime pun! Cool chess! (2021-05-03)
comment
Keywords: Joke (pun), Masand
Pieces: dl = Eagle (AD)
Genre: h#, Fairies
Computer test: C+ Popeye 4.61
FEN: 8/2*3q5/8/8/8/4pK2/5n1p/5qkr
Reprints: MatPlus.net Forum 4/4/2021
Input: A.Buchanan, 2021-04-29
Last update: Alfred Pfeiffer, 2021-07-27 more...
56 - P1389099
Silverbyte
Discord Chess Problems & Studies Server 4/4/2021
8. Platz
CP&S Discord Server Composition Tourney 0 {}
P1389099
(9+7) C+
#3
1. Df4+ Sxf4 2. exf4+ Kf6 3. Ld4#
play all play one stop play next play all
more ...
comment
Keywords: Joke, Non-standard material (Ds), Ornament (mate position)
Genre: 3#
Computer test: Henrik Juel: C+ Popeye 4.61 C+ Popeye 4.61 1.Df4+ Sxf4 2.exf4+ Kf6 3.Ld4# joke: non-standard material ornament: mate position
FEN: 2q2n2/3bn3/2r1n3/4k3/2Q1B1Q1/2P1PK2/3RP3/6B1
Reprints: MatPlus.net Forum 4
Input: A.Buchanan, 2021-04-30
Last update: Alfred Pfeiffer, 2021-07-27 more...
57 - P1389101
Siegfried Hornecker
Discord Chess Problems & Studies Server 4/4/2021
10. Platz
CP&S Discord Server Composition Tourney 0 {}
P1389101
(2+2)
Series mover. Exchange the position of two pieces as quickly as possible. What is the first and what is the last move?
Henrik Juel: 1.axb6 2.Ka7 .. 7.b1=DL 8.DLe4 9.DLa8
is faster than
1.a5 .. 5.a1=D .. 7.Dxb6 8.Ka7 .. 11.Da8 (2021-04-30)
comment
Keywords: Joke, Kindergarten Problem, Minimal, Miniature, Vielväterstellung, Seriesmover
Genre: Fairies
FEN: k1K5/p7/1P6/8/8/8/8/8
Reprints: MatPlus.net Forum 4/4/2021
Input: A.Buchanan, 2021-04-30
Last update: Alfred Pfeiffer, 2021-07-27 more...
58 - P1389102
Finneon
Discord Chess Problems & Studies Server 4/4/2021
11. Platz
CP&S Discord Server Composition Tourney 0 {}
P1389102
(3+8)
White to move, find the fastest helpstalemate (-:
Henrik Juel: 1... Kxd3 2.Df1+ Kd2 3.Dd3+ Kxd3
is faster than
1... Kxe1 2.d2+ Kf2 3.d1=T Ke2 3.Td3 Kxd3 (2021-04-30)
James Malcom: Henrik, much faster is 1. Kxd3 Qf2= (2021-04-30)
Henrik Juel: Yes indeed, James; I was assuming that Black was to be stalemated... (2021-05-01)
comment
Keywords: Joke
Genre: Fairies
FEN: 7k/3p2pP/3p2P1/3p4/3p4/3p4/3K4/4q3
Reprints: MatPlus.net Forum 4/4/2021
Input: A.Buchanan, 2021-04-30
Last update: Alfred Pfeiffer, 2021-07-27 more...
59 - P1389103
LilHamood
Discord Chess Problems & Studies Server 4/4/2021
12. Platz
CP&S Discord Server Composition Tourney 0 {}
P1389103
(3+2)
Make a legal move (-:
Henrik Juel: maybe 1.e8=K (2021-04-30)
comment
Keywords: Joke, Minimal, Miniature, Illegal position (no wK), Promotion (wK)
Genre: Retro, Fairies
FEN: 8/4P3/8/5N2/8/8/2Q3b1/7k
Reprints: MatPlus.net Forum 4/4/2021
Input: A.Buchanan, 2021-04-30
Last update: A.Buchanan, 2023-12-11 more...
60 - P1389104
Finneon
Discord Chess Problems & Studies Server 4/4/2021
13. Platz
CP&S Discord Server Composition Tourney 0 {}
P1389104
(7+2)
White to mate Black in 8, with the final mate given by an en passant capture
Henrik Juel: A miniature with many men (2021-04-30)
A.Buchanan: These days "Miniature" is added automatically when the diagram is created. But I hadn't added all the pieces yet, and when I did add them, the program didn't recheck apparently. (2021-04-30)
Henrik Juel: OK, Andrew, but I hope you will supply the intended solutions to all these weird problems (2021-05-01)
A.Buchanan: Will do (2021-05-02)
comment
Keywords: Constrained problem, Joke, Minimal (b)
Genre: n#
FEN: 2NK4/3p1k2/8/4PP2/1B6/8/2B5/7R
Reprints: MatPlus.net Forum 4/4/2021
Input: A.Buchanan, 2021-04-30
Last update: Alfred Pfeiffer, 2021-07-28 more...
61 - P1389106
Ethan Donaghue
Discord Chess Problems & Studies Server 4/4/2021
15. Platz
CP&S Discord Server Composition Tourney 0 {}
P1389106
(15+10)
Gewinn
("White to move and win (-:)
Henrik Juel: 1.Da8# (2021-04-30)
comment
Keywords: Joke, Illegal position, Non-standard material (TTTLLdddddd)
Genre: Studies
FEN: 1k1q1q2/1pq3q1/1p6/2q3q1/3q1N2/5BBB/Q4PPP/RRB1RRKR
Reprints: MatPlus.net Forum 4/4/2021
Input: A.Buchanan, 2021-04-30
Last update: Alfred Pfeiffer, 2021-07-28 more...
62 - P1389375
Andrew Buchanan
MatPlus.net Forum 22/01/2021
P1389375
(14+14) C+
PG in 7.0
Staugaard castling
1. g3 e6 2. Lg2 e5 3. Lxb7 e4 4. Sf3 exf3 5. 0-0 fxe2 6. Lxa8 e1=T 7. Lg2 0-0-0-0-0-0
play all play one stop play next play all
Objective: fastest Staugaard (Pam-Krabbé) + another castling (happens to be kside)
A.Buchanan: Now we know more about Conrad Staugaard and his life, I enthusiastically agree with Henrik's earlier suggestion that we change this theme to be "Staugaard", which would also align with WinChloe. I can make necessary changes in PDB as a batch, and retain also "Pam-Krabbe" as a deprecated keyword, pointing to Staugaard. Pam & Krabbé are famous already, and only popularized Staugaard's funny idea. Any objections? (2021-05-08)
A.Buchanan: OK thank you: I've made the move. Please check the definitions, and let me know anything that needs changing (2021-05-09)
Henrik Juel: Very good, Andrew; the Staugaard fan club (both of us) thanks you
You might want to add that after a white Staugaard castling, wK is on e3 and promoted wR is on e2
I wonder whether the solution notation should be changed to 0-0-0-0-0 with 5 zeroes, so that the number of zeroes is one less than the length of the rook displacement for all three castlings (2021-05-09)
Henrik Juel: Forget my very last remark, please
Short and long castling has rook displacement = number of zeroes,
so Staugaard should remain with 6 zeroes, of course (2021-05-09)
A.Buchanan: Ok listed the target squares as requested. (2021-05-09)
A.Buchanan: Curious that this economy record must begin with a tempo move (2021-05-20)
A.Buchanan: Staugaard seems a much better basis than Chess960 for further generalization of castling. Basically move an unchecked royal king 2 unattacked square towards the rook, and the rook hops the otherside. This works whatever the gap between the two. This is more similar to rokagogo. (2021-05-21)
more ...
comment
Keywords: Unique Proof Game, Staugaard castling, Castling (2), Phoenix (t), Promotion (t), Tempo Loss, Economy record, Pure Round Trip (L3)
Genre: Retro, Fairies
Computer test: HC+ no orthodox solution in 7.0, and last Bl move can only have been 0^6 (else switchback, taking more than 7 Bl moves in total). Retracting 0^6, C+ Euclide 1.01 in 6.5
FEN: 1nbq1bnr/p1pprppp/4k3/8/8/6P1/PPPP1PBP/RNBQ1RK1
Input: A.Buchanan, 2021-05-08
Last update: Rainer Staudte, 2024-02-28 more...
63 - P1390704
Hauke Reddmann
(1) MatPlus.net Forum 21/04/2014
P1390704
(8+2) C+
#2
1. Txa4? Patt!

1. Lb4? Patt!

1. Kc7!
1. ... axb3 2. Lb4#
1. ... Kxa5 2. Txa4#
play all play one stop play next play all
https://matplus.net/start.php?px=1623299118&app=forum&act=posts&fid=gen&tid=1448
Figuren-Rechteck a3c6
A.Buchanan: 1. b4? Patt too, but I guess not thematic, as there's no way to get a mate out of it (2021-06-11)
more ...
comment
Keywords: Minimal
Genre: 2#
Computer test: popeye 4.85
FEN: 8/8/kPK5/B1P5/p1P5/RPP5/8/8
Input: James Malcom, 2021-06-10
Last update: Alfred Pfeiffer, 2021-10-20 more...
64 - P1390927
Andrew Buchanan
v MatPlus.net Forum 26/06/2021
after Bedrich Formanek
P1390927
(11+2)
#1 (-:
9 solutions
PPRA (Partial PRA = PRA except ignore cases having no solution)
1) 1. g8=CM# R: 1. Kg6xCMh5 CMe4-h5+
2) 1. g8=AD# R: 1. Kg6xADh5 ADc2(d3,e4)-h5+++
3) 1. c8=GZ# R: 1. Kg6xGZh5 GZc2-h5+
4) 1. c8=GQ# R: 1. Kg6xGQh5 GQc2-h5+
5) 1. b8=GF# R: 1. Kg6xGFh5 GFd3-h5+
6) 1. bxa8=GE# R: 1. Kg6xGEh5 GEe4-h5+
7) 1. b8=N# R: 1. Kg6xNh5 Nd3-h5+
8) 1. g8=QN# R: 1. Kg6xQNh5 QNe4-f6-h5+
9) 1. h8=TP# R: 1. Kg6xTPh5 TPf5-h5+
Minor duals, with both mates separately provided elsewhere:
1) 1. g8=GR,b8=GR# R: 1. Kg6xGRh5 GRd3(e4)-h5+
2) 1. g8=MG,h8=MG# R: 1. Kg6xMGh5 MGc2(d3,e4)-h5+
play all play one stop play next play all
What was Black's last move? It can only have been Kg6-h5, fleeing check. But what was White's prior move: it could only have been a fairy piece moving to h5 from the diagonal c2-f5, discovering check. Then this piece was captured by bK. What kind of piece was it? The idea is that for each feasible piece, there should be exactly one corresponding promotion mate.

1) Camel = (1,3)-Leaper
2) Eagle
3) Gazelle = (3-5)-Leaper
4) Giraffe Quintessence = right-angle turn Girafferider, Giraffe = (1,4)-Leaper
5) Greater Leafhopper
6) Greater Treehopper
7) Nightrider
8) Quintessence = right-angle turn Nightrider
9) Rookhopper

Minor duals, where both solutions are separately provided elsewhere:
1) Gnurider
2) Marguerite = Eagle+Grasshopper+Hamster+Moose+Sparrow, only the first two sub-creatures are used)

Tries:
1)It looks as if one might rotate the board 180 degrees: 1. Bb3#! Not 1. b3+? Kxa3!
The position is legal because e.g. R: 1. g8=B+.
However this doesn't work because it's not thematic :)
2) It looks as if R: 1. Kg6-h5 c2-c3+ might be good. Who's to say in a fairy form that wL can't begin on b1? Well if you can show me a fairy piece which can throw other pieces around the board, then let's consider it, but fairy conditions are excluded here, for sanity's sake.

Would be cooks - but the soundness is protected by the halo of PPRA :)
Bishop Eagle, Boy Scout, Dabbaba, Equihopper, Lancer, Moarider Lion, Radial Leaper
AB: See P0001924. Bedrich Formanek is happy with his problem, but welcomes a larger zoo.

I think this is a kind of PRA problem (although PRA is defined currently only for castling and ep). A PRA problem is regarded has having one solution with many parts. So maybe that points the way how to stipulate the problem. The joke version PRA (= Partial PRA) says that PRA applies to all the parts that it does, but not to the others, particularly those with no solution).

It's clear that there are more pieces which would solve the problem. Why not Gnurider or Gazellerider instead of Gnu or Gazelle? Why not Gnurider instead of Nightrider? Etc. Why not Grasshopper instead of Rookhopper? The PRA notion would prevent these from cooking the problem: each is indeed a separate part. As long as whatever was just captured can be uniquely reborn to deliver mate, the problem is sound. The published solution shows the most basic representative piece for each of the patterns, with no unused capability.

As a PRA problem, if a kind of fairy piece might legitimately have been captured on h5, yet does not offer a mating promotion, that would make the problem unsound. And indeed there are two such creatures known: Dabbaba and Lancer. However fortunately we are working with the looser PPRA meta-convention which only applies where it applies.

In earlier versions, the eagle was considered a try, but actually I think it implied an insoluble PRA part, but fortunately could be fixed.
Henrik Juel: if last move was Kg6xGh5, 1.gxh8=G#
if last move was Kg6xYh5 (Y=1,3-S=Camel), 1.g8=Y#
if last move was Kg6xYh5 (Y=rookhopper), 1.gxh8=Y# (This looks like a cook)
if last move was Kg6xYh5 (Y=5,3-S), 1.c8=Y#
if last move was Kg6xNh5, 1.b8=N# (2021-06-20)
A.Buchanan: Thanks Henrik - as discussed: I don’t think Rookhopper is a cook, but is a separate part of the PRA solution. Maybe it’s the fundamental solution and Grasshopper is the one with unneeded additional functionality but Grasshopper is the more common one. Nice for some of these unfamiliar creatures to get some exposure... (2021-06-20)
comment
Keywords: Joke (PPRA), Phoenix (9), Last Moves?, Partial Retro Analysis (PRA), Rex solus, Promotion (9), Minimal
Pieces: tu = Rookhopper (TP), sr = Camel (CM), su = Nightrider (N), lu = Gazelle (GZ), dl = Eagle (AD), sl = Quintessence (QN), lr = Giraffe Quintessence (QG), du = Greater Treehopper (GE), dr = Greater Leafhopper (GF)
Genre: Retro, Fairies
FEN: b7/1PP3PP/7B/6Pk/8/2P3K1/P3P3/1B6
Input: A.Buchanan, 2021-06-19
Last update: A.Buchanan, 2022-01-09 more...
65 - P1394373
Michel Caillaud
Andrew Buchanan

MatPlus.net Forum 29-08-2021
P1394373
(14+14) C+
PG in a) 7.0 b) 7.5
Staugaard castling
a) 1. e4 f5 2. e5 Sf6 3. exf6 Kf7 4. fxe7 Kf6 5. e8=T La3 6. 0-0-0-0-0-0 Lxb2 7. Kd3 Lxa1
b) 1. e4 f5 2. e5 Sf6 3. exf6 Kf7 4. fxe7 Kf6 5. e8=T La3 6. Ke2 Lxb2 7. Kd3 Lxa1 8. Te2
play all play one stop play next play all
Engine shows orthodox solution in 7.5 and nothing shorter. Staugaard implies at least 7 White moves of which 2 are captures to promote on d8. So Black needs 7 moves. sL only released after W5 promotion, so last 3 Black moves are with bishop. If 7.0 moves exactly, then can use engine for first 5.0, which has unique solution. If 7.5, then White must lose a tempo. b2-b4 is too late, so must be with wK. But cannot triangulate via e4 or d4 because of checks. So no Staugaard castling in 7.5.
Henrik Juel: Part b) is an orthodox proof game, which is C+ Euclide 1.01
The solution is
1. Be2-e4 Bf7-f5 2. Be4-e5 Sg8-f6 3. Be5xf6 Ke8-f7
4. Bf6xe7 Kf7-f6 5. Be7-e8=T Lf8-a3 6. Ke1-e2 La3xb2
7. Ke2-d3 Lb2xa1 8. Te8-e2
In part a) you can save a white move by Staugaard castling
1.-5. as above, then 6. 0-0-0-0-0-0 Lxb2 7. Ke3-d3 Lxa1
Note that after this castling you cannot reach 7.5 moves by going Ke3-e4-d3 or Ke3-Kc4-d3, so part b) is also correct as a fairy proof game (2021-10-05)
Henrik Juel: Trying to waste a white move early in part b) also fails
1.e3? f5 2.e4 Sg6 3.e5 Kf7 4.exf6 Kf6??
because Black cannot make his 4th move (2021-10-05)
Henrik Juel: 2... Sg6 should be Sf6, of course (2021-10-05)
comment
Keywords: Unique Proof Game, Staugaard castling, Promotion (T), Prenix (T)
Genre: Retro, Fairies
Computer test: a) HC+ Popeye v4.87 for first 5.0 + reasoning: see Solution Text b) C+ Popeye v4.87 in 7.5 and and not shorter
FEN: rnbq3r/pppp2pp/5k2/5p2/8/3K4/P1PPRPPP/bNBQ1BNR
Input: A.Buchanan, 2021-10-04
Last update: A.Buchanan, 2021-10-06 more...
66 - P1394375
Michel Caillaud
MatPlus.net Forum 29/08/2021
P1394375
(14+16) C+
KBP a) orthodox b) Staugaard castling
a) 1. d3 e5 2. Sd2 e4 3. Sdf3 exf3 4. Ld2 fxe2 5. f3 f6 6. Kf2 e1=T 7. Kg3 Te7 8. Le1 Kf7 9. Dd2 Ke6
b) 1. Sc3 e6 2. Sd5 exd5 3. f3 d4 4. Kf2 d3 5. Kg3 dxe2 6. d3 e1=T 7. Ld2 0-0-0-0-0-0 8. Le1 f6 9. Dd2
play all play one stop play next play all
Given a) is C+ at 9.0, any shorter Staugaard solution can only be 8.5, as wS must still move twice to be captured (whether d-file or f-file). So Bl has 8 moves, of which exactly 6 are visible. To lose one tempo, Black must have begun 1... e6. The castling must have been B7 at earliest, but then Wh has Ld2-e1, Dd1-d2 to come. So castling was exactly B7, and the game ended. 7. ... 0^6 8. Le1 f6 9. Dd2. Can use engine to validate PG in 6.5 for proof.
more ...
comment
Keywords: Unique Proof Game, Staugaard castling, Non-standard material (t), Promotion (t)
Genre: Retro, Fairies
Computer test: a) C+ Euclide 1.01 in 9.0 and not shorter b) HC+ Popeye v4.87 for first 6.5 + reasoning: see Solution Text
FEN: rnbq1bnr/ppppr1pp/4kp2/8/8/3P1PK1/PPPQ2PP/R3BBNR
Input: A.Buchanan, 2021-10-04
Last update: A.Buchanan, 2021-10-06 more...
67 - P1395488
Thomas R. Dawson
Tidskrift för Schack 1923
P1395488
(15+9) cooked
#2
1. axb6ep+! Kxe3 2. De2#
play all play one stop play next play all
Cooked by the possibility of e2-e1=S!

https://timkr.home.xs4all.nl/admag/promo.htm Tim Krabbe writes in "PROMOTIEMOTIVATIE": Een van de mooiste uitspraken in de Nederlandse schaakliteratuur werd gedaan door Johan Barendregt (1924-1982), in een interview met Max Pam: 'Mijn leven is bepaald door de zet e2-e1P.'

Hij doelde daarmee op een ontdekking die hij had gedaan in een stelling die in 1937 aan de lezers van het blad De Schaakwereld ter oplossing was voorgelegd. (Zie diagram.)
Het mat op zich was niet moeilijk, dat kon alleen 1.axb6+ Kxe3 2.De2 mat zijn, maar het ging om het bewijs dat alleen b7-b5 Zwarts laatste zet geweest kon zijn, en niet b6-b5 of Kc4-d3. Toen een paar weken later de oplossing werd gepubliceerd, bleek dat de 13-jarige Barendregt alle oplossers de baas was geweest, omdat hij had aangetoond dat het probleem van de grootheid Dawson incorrect was. Met een bewijspartij van 48 zetten liet hij zien dat ook e2-e1P Zwarts laatste zet geweest kon zijn, wat 1.axb6 illegaal maakte. En passant repareerde hij het probleem ook, door de pion van f5 naar e7 te verplaatsen - dàn moet Zwart zojuist b7-b5 gespeeld hebben.
Dat bewijs laat ik hier voor wat het is - het gaat me om de verrukking die Barendregt moet hebben gevoeld toen hem, temidden van de partijen van Euwe, Aljechin en Keres, lof werd toegezwaaid, maar die hij vooral moet hebben gevoeld bij de ontdekking van e2-e1P zèlf. Dat geluksgevoel bond hem voor de rest van zijn leven aan het schaken - hij was jarenlang een van de sterkste Nederlanders, werd Internationaal Meester toen dat nog iets betekende, en won partijen tegen Botwinnik en Portisch.

In English: One of the most beautiful statements in Dutch chess literature was made by Johan Barendregt (1924-1982), in an interview with Max Pam: 'My life is determined by the move e2-e1P.'

He was referring to a discovery he had made in a proposition that had been submitted to the readers of the magazine De Schaakwereld in 1937 for a solution. ( See diagram. )
The mate itself was not difficult, only 1.axb6+ Kxe3 2.De2 ??mate but it was to prove that only b7-b5 could have been Black's last move, and not b6-b5 or Kc4-d3. When the solution was published a few weeks later, it turned out that 13-year-old Barendregt had beaten all the solvers because he had shown that the problem of the great Dawson was incorrect. With a proof game of 48 moves, he showed that e2-e1P could also have been Black's last move, making 1.axb6 illegal. In the meantime, he also solved the problem by moving the pawn from f5 to e7 - then Black must have just played b7-b5.
I will leave that proof for what it is here - I am concerned with the delight that Barendregt must have felt when he was praised among the parties of Euwe, Aljechin and Keres, but which he must have felt above all when he discovered e2-e1P itself. That happiness tied him to playing chess for the rest of his life - for years he was one of the strongest Dutchmen, became an International Master when it still meant something, and won games against Botvinnik and Portisch.
Cook: Possible proof game by James Malcom in 42.0 moves: 1. b4 a5 2. bxa5 g5 3. Lb2 g4 4. Sc3 g3 5. hxg3 Sf6 6. Th6 Se4 7. Sd5 Sc3 8. Tc1 Sb1 9. Ta6 e5 10. Sf6+ Ke7 11. e4 d5 12. c3 d4 13. Tc2 d3 14. Ta7 dxc2 15. Sh3 Sa6 16. d4 c6 17. d5 Sc7 18. La6 Kd6 19. Dd3 Kc5 20. d6 Lh6 21. Ke2 Ld2 22. dxc7 h5 23. Sg5 Dd5 24. exd5 e4 25. a3 e3 26. Kf3 h4 27. De2 Lf5 28. Kf4 Tae8 29. Ta8 h3 30. Tc8 h2 31. d6 h1=T 32. Sd5 Tc1 33. f3 Le4 34. fxe4 b5 35. Dd1 Th4+ 36. Kf5 Tf4+ 37. gxf4 Kc4 38. Sh7 Kd3 39. Kg5 f5 40. Shf6 e2 41. Se3 Te5 42. fxe5 e1=S
means e.p. convention won't fire
Henrik Juel: James, when I played your game I did not reach the diagram position
Is the diagram or your game wrong? (2021-11-06)
James Malcom: Gahhhhh, I got myself again Henrik. I garbled some pawns, which should be fixed now. (2021-11-06)
Henrik Juel: Thanks
The intended retroplay was
R: 1... b7-b5! 2.Sc4-d3+ Ke3-d3+ 3.Sb6-c4+ d3xTc2 (2021-11-07)
Henrik Juel: The cooking last move e2-e1=S is rather obvious
I would have thought that it was found by the TfS solvers and corrected by TRD
Can anyone check in TfS 1923-24? (2021-11-07)
Henrik Juel: Never mind...
The problem appeared in October 1923, and there is no mention of e2-e1=S in the solution in the March 1924 issue (2021-11-07)
comment
Keywords: En passant as key, Superseded by (P1395505)
Computer test: Popeye v4.87 & simple retro-logic & demonstrative proof game
FEN: 2R5/2P5/B1pP1N2/Pp2PpK1/4P3/P1PkN3/1Bpb2P1/1nrQn3
Reprints: De Schaakwereld 1937
Tim Krabbé's Website 2001
MatPlus.net Forum 2021
Input: James Malcom, 2021-11-06
Last update: A.Buchanan, 2021-11-07 more...
68 - P1395505
Thomas R. Dawson
Johan Barendregt

De Schaakwereld 1937
TRD, correction JB
P1395505
(15+9) C+
#2
1. axb6ep+ Kxe3 2. De2#
R: 1. b7-b5 2. Sc4-e3+ Ke3-d3+ 3. Sb6-c4+ d3xTc2
play all play one stop play next play all
Correction of P1395488
Henrik Juel: Black captured d3xTc2 and promoted on h1
White captured bxPa, d6xc7, exd, fxe, and h2xPg3xf4xe5
R: 1... b7-b5 2.Sc4-e3+ Ke3-d3+ 3.Sb6-c4+ d3xTc2
Yet another way to motivate the double step b7-b5
Solution 1.axb6ep+ Kxe3 2.De2# (2021-11-07)
comment
Keywords: En passant as key
Genre: 2#, Retro
Computer test: HC+ Popeye v4.87 & simple retro-logic
FEN: 2R5/2P1p3/B1pP1N2/Pp2P1K1/4P3/P1PkN3/1Bpb2P1/1nrQn3
Reprints: Tim Krabbé's Website 2001
MatPlus.net Forum 2021
Input: A.Buchanan, 2021-11-07
Last update: A.Buchanan, 2021-11-07 more...
69 - P1400919
Arno Tüngler
Michael Schreckenbach

MatPlus.net Forum 22/04/2022
P1400919
(5+16) C+
ser-=19
1. Lh5 2. g4 3. g5 4. g6 5. gxh7 6. hxg8=D 7. Dxh8 8. Dxg7 9. Dg1 10. Dxa7 11. Dxa8 12. Dxb8 13. Dxc7 14. Db6 15. c7 16. cxd8=L 17. Lxe7 18. Lxf8 19. Ld6=
play all play one stop play next play all
Henrik Juel: Good problem, where the black homebase is not just an ornament (2022-04-27)
comment
Keywords: Homebase (s), Move Length Record, Construction task, Seriesmover
Genre: Fairies
Computer test: O. Jenkner: Gustav 4.2 a
FEN: rnbqkbnr/pppppppp/2P5/4P3/6B1/8/6P1/7K
Input: Olaf Jenkner, 2022-04-27
Last update: Olaf Jenkner, 2022-06-05 more...
70 - P1401567
Andrew Buchanan
Discord Chess Problems & Studies Server 31/05/2022
P1401567
(4+1)
ser-h#n
How many solutions, including all shorter ones!
(ignore draw by repetition & 50 move rule)
1. Kh8 Dh6#
1. Kf8 2. Ke8 Tg8#
1. Kf8 2. Ke8 3. Kd8 Tg8#
1. Kf8 2. Ke8 3. Kd8,Kf8 4. Ke8 Tg8#

play all play one stop play next play all
Solutions in exactly:
1,1,1,2,3,5…
Solutions in up to n:
1,2,3,5,8,13…
and both sequences seem to be more-or-less Fibonacci. What’s going on?

Let's look at something apparently irrelevant: Peg Solitaire (aka Conway's Soldiers). https://en.wikipedia.org/wiki/Peg_solitaire

In this, a peg hops 2 squares orthogonally, capturing the mandatory hurdle. (Is there a fairy chess piece with this movement?) Imagine a long line of them. e.g.
.1234567890abcde.

(We put a space at each end to show the termination.) Split them conceptually into two alternating lines:
.1.3.5.7.9.a.c.e.
&
..2.4.6.8.0.b.d..

No captures can be made, but if we "borrow" one additional peg on the left of each line:
*1.3.5.7.9.a.c.e.
&
.*2.4.6.8.0.b.d..

then these two pegs can hop over all the other pegs in their lines:
................f
&
...............e.

Then combining them again, e can capture f:
.................g

Fibonacci numbers behave exactly the same way when you add them! There is a capturing rule: f(n) = f(n-1) + f(n-2). Then:
sum(k=1...n-1)f(k) = f(n+1) - f(0) - f(1)

The two correction terms correspond to the "*" terms that we added on the left in order to get the cascade started!

So back to chess. Ignoring for now the odd solution with n=1, the number of ser-h#n in EXACTLY n moves is f(n-1), where f(k) is the kth fibonacci number 1,1,2,3,5,8,13,21,34...

[This comes from bK being able to occupy just 4 squares.
A(n) is the number of ways to reach d8 or e8 in n moves, B(n) is the number of ways to reach c8 or f8.
A(n+1) = A(n)+B(n)
B(n+1) = A(n)
You can see that this formula is just the "capturing rule" again.
And to get started: A(1)=0,B(1)=1.
So A(n)=B(n+1)=f(n-1).]

To find all the solutions in UP TO n moves, we need to sum them together:
sum(k=1...n-1)f(k) = f(n+1) - f(0) - f(1)

f(0)+f(1) is just 0+1=1. So this is why we need the extra solution with bKh8.

"Summing it all up", the number of ser-h#n is just f(n+1).

Noam's earlier setting https://pdb.dieschwalbe.de/P1243505 is the first afaik to show the whole Fibonacci sequence, and is one of two he published with the 4-chain (see also P1243525). This problem also uses a 4-chain as the easiest way to get Fib going, but (1) concentrates the mates onto just 2 of the 4 squares in the chain, (2) tots up the cumulative sum from 1 to n, and (3) exploits the curious diversion to h8. And is a seriesmover, as there's not much interest in the two-sided play.

The earlier https://pdb.dieschwalbe.de/P1259074 was the first I think to show a Fibonacci number.

What happens if the BK has more than the 4 free squares? There is a sneaky trick to get the answer quickly: instead of an n-chain, consider a (2n+2)-cycle:

x-x-x-x-x-x =>

x-x-x-x-x-x
|...............|
x..............x
|...............|
x-x-x-x-x-x

n-cycles are more symmetric than n-chains, so easier to analyze.

Counting paths in a graph systematically involves finding the "resonances", termed eigenvalues, which for a graph are always real numbers. The long-term growth rate in the number of paths is dominated by the eigenvalues with largest magnitude. It turns out that the eigenvalues of n-chain & (2n+2)-cycle are mostly the same! The dominant eigenvalues of the (2n+2)-cycle are +-1, but those are the only ones which *don't* carry over to the n-chain. The other eigenvalues are 2*cos(j*pi/(n+1)) for j=1..n, and they *do* carry over. The largest are where j=1 or n, and have opposite sign. We can ignore the sign from the perspective of the overall growth rate, but it's this sign that gives the "parity" in the n-chain paths: they either have odd or even length.

So the growth rate of an n-chain is 2*cos(pi/(n+1)). This "explains" why the golden ratio (which contains _/5) is the growth rate when n=4, which doesn't seem to have anything to do with 5.

Here's a few values of growth rates from n=1 upwards:
1-chain: 0 (no movement can happen)
2-chain: 1 (just deterministic pendulum)
3-chain: _/2 ~= 1.4142
4-chain: golden ratio = (1+_/5)/2 ~= 1.618
5-chain: _/3 ~= 1.7321
6-chain: ~= 1.8019
7-chain: ~= 1.8477
etc.

Some other random observations. As n increases, so does the growth rate, but it will always be less than 2 because the n-chain is a subgraph of the n-cycle (just missing 1 edge), and the n-cycle always has a growth rate of 2. The growth rate increases with n, because the missing edge is increasingly negligible. There is also a recursive formula for the polynomial of degree n, p_n(t) which contain the eigenvalues as roots:
p_n = - t*p_(n-1) - p_(n-2)
which is reminiscent of both Fibonacci & Pascal, although is more general.
Previous problems of this kind were "exact", excluding short solutions. Here's one where, for a given n, you need to tot up *all* the solutions with m less than or equal to n into a nice sum.
Henrik Juel: n=1, 1.Kh8 Dh6#, total t=1
n=2, 1.Kf8 2.Ke8 Tg8#, t=2
n=3, 1.Kf8 2.Ke8 3.Kd8 Tg8#, t=3
n=4, t=5
After this it gets a little hairy, but Andrew will give the nice sum next week... (2022-06-03)
A.Buchanan: Nice sum supplied :) (2022-06-08)
Henrik Juel: Thanks, Andrew
So the nice sum is t=f(n+1), where f are the Fibonacci numbers given by
f(1)=f(2)=1, f(n)=f(n-1)+f(n-2) for n=3,4,..
n 1 2 3 4 5 6
f 1 1 2 3 5 8
t 1 2 3 5 8 (2022-06-08)
more ...
comment
Keywords: Path enumeration (Fibonacci), Aristocrat, Miniature, Rex solus (s)
Genre: Fairies, Mathematics
FEN: 6k1/6R1/N3K3/8/8/4Q3/8/8
Reprints: MatPlus.net Forum 31/05/2022
Input: A.Buchanan, 2022-06-02
Last update: A.Buchanan, 2022-06-08 more...
71 - P1401782
Michel Caillaud
MatPlus.net Forum 10/06/2022
P1401782
(13+16) cooked
ser-h=35
1. axb6 2. Txa6 3. Txa5 4. Ta4 5. Txc4 6. Txd4 7. Txd5 8. Txc5 9. Txc6 10. Te6 11. c6 12. d5 13. d4 14. d3 15. d2 16. d1=T 17. Dd2 18. Dh6 19. Td8 20. Sd7 21. c5 22. c4 23. c3 24. c2 25. c1=L 26. Lg5 27. Lf6 28. g5 29. Dg7 30. h6 31. Th7 32. Dh8 33. L6g7 34. Tg6 35. f6 e6=
play all play one stop play next play all
Cook: 1. axb6 2. Txa6 3. Txa5 4. Ta4 5. Txc4 6. Txc5 7. Txc6 8. Te6 9. c5 10. c4 11. c3 12. c2 13. c1=L 14. Lh6 15. g5 16. Lfg7 17. Sf6 18. 0-0 19. d6 20. Dd7 21. Td8 22. De8 23. Kf8 24. Sg8 25. Sd7 26. Tg6 27. f6 28. Lh8 29. 29. Df7 30. Ke8 31. Tg7 32. Df8 33. Tf7 34. L6g7 35. h6 e6=
Für die kürzere Version (P1409325) ohne zusätzliche weiße Steine wurde noch keine Inkorrektheit gefunden.
Michel Caillaud: cooked by Arno Tüngler :
1.S×ç6 2.Sb4 3.S×a6 4.ç6 5.Sç7 6.ç×d5 7.d×ç4 8.ç3 9.ç2 10.ç1=L 11.Lb2 12.a×b6 13.T×a5 14.Ta4 15.T×d4 16.Td6 17.L×é5 18.g5 19.Lég7 20.Lh6 21.Tg6 22.f6 23.Lfg7 24.Kf7 25.Df8 26.Ké8 27.Kd8 28.Dé8 29.Lf8 30.Tg7 31.Tf7 32.Lfg7 33.Df8 34.Ké8 35.Sé6 S×é6=
or
1.a×b6 2.T×a6 3.T×a5 4.Ta4 5.T×ç4 6.T×ç5 7.T×ç6 8.Té6 9.ç5 10.ç4 11.ç3 12.ç2 13.ç1=L 14.Lh6 15.g5 16.Lfg7 17.Sf6 18.0-0 19.d6 20.Dd7 21.Td8 22.Dé8 23.Kf8 24.Sg8 25.Sd7 26.Tg6 27.f6 28.Lh8 29.Kf7 30.Df8 31.Ké8 32.Tg7 33.Tf7 34.L6g7 35.h6 é6= (2022-08-02)
Anton Baumann: Mit der korrigierten Stellung geht die 1. NL nicht: 35.Se6 Sxe6??
Bei der 2. NL geht 29.Kf7 nicht, aber 29.Df7 30.Ke8 31.Tg7 32.Df8 33.Tf7 34.L6g7 35.h6 e6 = (mit ZU) (2023-05-05)
Olaf Jenkner: Die ursprüngliche Version hatte getauschte Steine auf c4 und c5 und einen Turm auf d5.
Dazu wurden zwei Nebenlösungen gefunden, siehe Post von M. Caillaud,
Die vorliegende Version hat weiterhin die zweite Nebenlösung mit Zugumstellung in den
Zügen 29 bis 32. (2023-05-05)
more ...
comment
Keywords: Homebase (s), Seriesmover, Capture key, konsekutive Umwandlungen 2 (tl), under-promotion (tl), pin-stalemate, Pawn mate (-patt), blocking of a piece
Genre: Fairies
FEN: rnbqkbnr/pppppppp/PPN5/BBPQPK1P/2NP2P1/8/8/8
Input: Olaf Jenkner, 2022-06-11
Last update: Olaf Jenkner, 2023-05-05 more...
72 - P1409814
Dmitri Turevski
Dmitri V. Zhylko
Andrew Buchanan

MatPlus.net Forum 9/9/2022
in memoriam Dmitri Zhilko
DT & DZ, version AB
P1409814
(7+14) C+
h#3
b) Tf1 nach g1
a) 1. Da3 Txc3 2. Dxc3 La1 3. Dxd4 Lxd4#
b) 1. Da1 Lxc3 2. Dxc3 Ta3 3. Dxf3+ Txf3#
play all play one stop play next play all
See P1253418.
more ...
comment

Genre: h#
Computer test: C+ Popeye 4.87
FEN: 8/8/8/p2p4/1ppP1p2/1Rp2P1K/qBp1pkPP/2rbbr2
Input: A.Buchanan, 2023-05-19
Last update: A.Buchanan, 2023-05-20 more...
73 - P1410861
James Malcom
Siegfried Hornecker
Joaquim Crusats
Andrew Buchanan

12 MatPlus.net Forum 25/06/2023
P1410861
(16+4)
What is curious about this position?

Fewest Black pieces requiring all 16 White pieces in a legal checkmate position

https://matplus.net/start.php?px=1689032781&app=forum&act=posts&fid=gen&tid=3043
A.Buchanan: Mu-Tsun Tsai suggests that for construction problems such as this, the stipulation might be "What is curious about this position?" (2023-07-13)
James Malcom: That feels apt. (2023-07-14)
more ...
comment
Keywords: Superseded by (P1410903)
Genre: Retro, Fairies
FEN: B1Qr2RK/3P2N1/1P4RB/1rP5/4kP2/PPP5/q2P4/2N5
Input: James Malcom, 2023-07-11
Last update: A.Buchanan, 2023-07-27 more...
74 - P1410903
Mu-Tsun Tsai
Dream Yeh

MatPlus.net Forum 14/07/2023
P1410903
(16+2)
What is curious about this position?
R: 1. d5xe6ep# e7-e5 2. d4-d5+
play all play one stop play next play all
Mu-Tsun Tsai: Previous record is P1410861 (2023-07-14)
Mu-Tsun Tsai: Original design was 8/2N5/3PPkPR/rP6/B5PP/8/3PPN2/B2RqQK1, but that leads to a surprising cook: remove both d2 and f2, and retract -1. fxe6ep# e7 -2. Rd4+! (2023-07-14)
comment
Keywords: Economy record, En passant, En passant in the retro play, Last Moves? (3), Minimal
Genre: Retro, Fairies
FEN: 3Q1R2/2N1PP2/5k2/7P/2P4P/6N1/3PPP2/B2BqRK1
Input: James Malcom, 2023-07-14
Last update: James Malcom, 2023-09-09 more...
75 - P1411115
Miguel Ambrona
MatPlus.net Forum 2021
P1411115
(2+4) C+
h#3
1. Db8! Kf7 2. Lh8 e7 3. Df8+ exf8=S#
play all play one stop play next play all
Henrik Juel: 1. Db8 Kf7 2. Lh8 e7 3. Df8+ exf8=S# (2023-07-24)
Henrik Juel: Congratulations, Miguel
This the first correct entry by you, I believe
It still needs author and source, though (and possibly a twin) (2023-07-24)
A.Buchanan: Hi Henrik, we are working to automate the process of uploading these problems. It will take a day or so, after that should be smooth. (2023-07-25)
Miguel Ambrona: Thanks Henrik!
This is a problem I composed a few years ago, before I know about the notion of twin. I may work on it at some point.
:) (2024-01-14)
more ...
comment
Keywords: Minimal (B), Miniature, Selfblock, under-promotion in mating move (S)
Genre: h#
Computer test: Juel: Popeye 4.61
FEN: 8/4K2k/4P2p/8/3b1q2/8/8/8
Reprints: MatPlus.net Forum 2021
Input: Miguel Ambrona, 2023-07-24
Last update: Dieter Berlin, 2024-01-14 more...
76 - P1411845
James Malcom
MatPlus.net Forum 15/08/2023
After David Zimbeck
P1411845
(12+12)
#15
1. a8=D+! Kxb6 2. Da7+ Kxa7 3. Ta8+ Kb6 4. b8=D+ Txb8 5. cxb8=D+ Kc6 6. Dd6+ Kxd6 7. d8=D+ Ke5 8. e8=D+ Kf4 9. Dg5+ Kxg5 10. g8=D+ Sxg8 11. hxg8=D+ Kf4 12. f8=D+ Ke3 13. Dxf3+ Kxf3 14. Dh5+ Ke3 15. Dg3#
14. ... Kf4 15. Dgg5#
10. ... Kf4 11. f8=D+ Ke3 12. Dxf3+ Kxf3 13. Dh5+ Sg4 14. Dgxg4+ Ke3 15. Dg3#,Dhh3#
11. ... Sf5 12. Dxf5+ Ke3 13. Dxf3+ Kxf3 14. Dh5+ Ke3 15. Dg3#
14. ... Kf4 15. Dgg5#
play all play one stop play next play all
Record of 8 white queen promotions
Improvement of P1201958
https://www.matplus.net/start.php?px=1692327608&app=forum&act=posts&fid=gen&tid=3061&pid=25076#n25076
Schade um das dualistische Matt. Im strengen Sinn also kein Rekord.
SCHRECKE: sTg8 gehört nach f8! (2023-08-18)
James Malcom: Fixed. (2023-08-18)
SCHRECKE: Der wSb6 ist überflüssig!! (2023-08-18)
James Malcom: That's a surprise. (2023-08-18)
comment
Keywords: Promotion (DDDDDDDD x8), Construction record, Promotion key, konsekutive Umwandlungen 8 (DDDDDDDD), Checking key, Schlüssel = Eckzug, Phoenix, Antiphönix, Switchback (k)
Computer test: Popeye 4.87 Gustav
FEN: 1R3r2/PPPPPPPP/kN5n/1pp5/1n1bp3/2r2p2/1Kbq4/7N
Input: James Malcom, 2023-08-18
Last update: Gunter Jordan, 2023-08-18 more...
77 - P1413388
Arno Tüngler
MatPlus.net Forum 28/07/23
P1413388
(15+16)
ser-h=18
1. a5 2. axb4 3. Ta5 4. Tb5 5. d5 6. d4 7. dxc3 8. Dxd2 9. Sd7 10. Te5 11. Txe3 12. Tg3 13. Dxh6 14. Dg6 15. h6 16. Dh7 17. Tg6 18. f6 Lxc7=
play all play one stop play next play all
Shortest Ser-h= from the black homebase.
Henrik Juel: Interesting record (2023-11-07)
comment
Keywords: Homebase (s), Seriesmover
Genre: Fairies
FEN: rnbqkbnr/pppppppp/1R2P2P/5P1B/QN6/1PN1R3/2PP2PB/6K1
Input: Arno Tüngler, 2023-11-07
Last update: Arno Tüngler, 2023-12-29 more...
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The problems of this query have been registered by the following contributors:

Gerd Wilts (2)
Erich Bartel (1)
A.Buchanan (40)
James Malcom (29)
Felber, Volker (1)
Olaf Jenkner (2)
Miguel Ambrona (1)
Arno Tüngler (1)