Die Schwalbe

53 problem(s) found in 1969 milliseconds (displaying 53 problem(s)). [COMMENTDATE>=20200919 AND G='Retro']

1 - P0000775
Ferad Kakabadze
1422 Die Schwalbe 30 12/1974
(11+5) C+
Welches waren die letzten 2 Einzelzüge?
1. e8=D! f5 2. exf6ep e5 3. Dxe5#
R: 1. b2-b1=L 0-0
play all play one stop play next play all
Henrik Juel: The forward play is C+ Popeye 4.61
1.e8=D thr. 2.Dc8 thr. 3.Dc3#
1... f5 2.exf6ep e5 3.Dxe5#
(1... f6 does not prevent the threat, so 2.exf6 is not considered dualistic) (2020-09-26)
more ...
Keywords: Last Moves?, Valladao Task, En passant, Promotion, Castling in the retro play, Obtrusive material
Genre: Retro, 3#
FEN: 8/3pPp2/3Pp3/4P3/1N3P2/B7/P1P2P2/kb3RK1
Input: Gerd Wilts, 1995-06-03
Last update: James Malcom, 2020-09-27 more...
2 - P0000793
Nikita M. Plaksin
Andrey Lobusov

1558 Die Schwalbe 33 06/1975
4. Preis
(13+5) C+
#3 (AP)
1. cxd6ep+! Kxg3 2. 0-0! (proving ep ok)
2. ... Kg4 3. g8=D,T#
2. ... a1=D,L 3. Dg5#

R: 1. d7-d5 Tc6xh6 (unless R: Kg1-g2 Th~*h1)
play all play one stop play next play all
VL: A posteriori (AP)!
2.g8Q(R)+/Rg1+? Kf4 3.Qg5#??
Retro: d7-d5, Rc6xh6+ (unless Kg1-g2, Rh~-h1+).
One of the best AP-type problems. (2015-08-20)
James Malcom: The first Valladao AP? (2020-10-03)
A.Buchanan: Hi James, there are 6 earlier ones in PDB, not counting those which are not marked as Valladao (could quite a few, as basic AP is 2/3 of Valladao). Type k='a p' and not g='fairies' and k='valladao', and set sort order by date. The ur-problem is P0003417. (2020-10-03)
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Keywords: Castling (wk), a posteriori (AP), En passant as key, Promotion (ws), Valladao Task (w w w/s)
Genre: Retro, 3#
Computer test: Popeye v4.85 + minor retro/AP thought
FEN: B7/p5PP/p6R/Q1Pp4/8/PP1P2P1/p3P1k1/4K2R
Reprints: (B) Die Schwalbe 48 12/1976
feenschach 40 11-12/1977
Input: Gerd Wilts, 1995-06-03
Last update: A.Buchanan, 2020-10-03 more...
3 - P0003337
Rudolf Buljan
Problem 41-44 03/1957
2. Preis
15. Thematurnier
(11+15) C+
1. ... exf6ep 2. Sf5 f7#
play all play one stop play next play all
Autor Ing. Rudolf Buljan, Zagreb
Henrik Juel: Analysis
White captured fxg and promoted [Pd2] on d8
Black captured axbxa2-a1=Y, b7xc6, d5xe4, and gxf
The retroplay was R: 1... f7-f5 2.f5xYg6
C+ Popeye 4.61 (2020-09-30)
A.Buchanan: Any ideas how to distinguish usage of “whose move?” and “no legal last move for white” (or black) keywords (2020-10-01)
Henrik Juel: This problem is clearly the latter
I would use 'Whose move?' in retro problems where a deeper analysis is required to determine the move, often with stipulations like '#1 (who?)' (2020-10-01)
Keywords: En passant as key, No legal last move for White
Genre: h#, Retro
Computer test: Popeye 4.61
FEN: 5nkb/1qp1p1n1/2p3PQ/4PpKb/4prRp/P4prB/1PP3PP/8
Input: Gerd Wilts, 1995-06-03
Last update: James Malcom, 2020-10-01 more...
4 - P0003417
John Frederick Keeble
2206 The Problemist FCS 16, p. 173, 02/1936
(4+5) C+
Weiß zieht an
1. ... exd6ep 2. 0-0-0 dxe7+ 3. Tf8 exf8=T,D#
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H.Juel: If Black may castle, last move was not made by Ke8 or Ta8, but by Pd5, so it was d7-d5, and hence White may capture en passant. 1... exd6ep 2.0-0-0 dxe7 3.Tf8 exf8=DT# where the castling (belatedly) justifies the e.p. capture.
Not 1... exd6ep 2.Kd8? dxe7 3.Kc8 e8=DT
C+ by Popeye 4.61, except for the promotion mate dual, which was considered acceptable in the old days.
Nachdruck in "Die Schwalbe" 33 mit Diagrammfehler (wBe6 fehlt).
VL: The first AP-problem! Thematic illegal try:
1. ... exd6ep 2.Kd8? dxe7+ 3.Kc8 e8=T(D)#?? (2007-02-11)
Mario Richter: 46 years between this Problem and P1366663 - perhaps this was not Keeble's first AP-Problem?! (2019-08-29)
Ladislav Packa: Of course I know the idea a posteriori. But let my heresy be forgiven - I do not consider it logical. In this particular example, I consider e.p. for proof that black can castling - not vice versa. (2019-08-29)
A.Buchanan: Hi Ladislav. If ep is ok, then Black just moved a pawn with double hop. That doesn't stop Black having e.g. moved bK right at the beginning of the game. So you can't prove that Black definitely can castle this way. What am I missing here? (2019-08-29)
Ladislav Packa: Your statement is perfectly fine. However, the AP condition is usually interpreted as castling is evidence of e.p. However, the second party does not have to do castling - the possibility has already been demonstrated by the existence of e.p. (2019-08-29)
A.Buchanan: Hi again Ladislav. Please try again, I am obviously being very stupid. I don't understand how 1. exd6ep is any more indicative that Black can castle than 1. K~. (2019-08-30)
Ladislav Packa: Hi, Andre!
e.p. is just a result of the d7-d5 move. Black can castle only if it was the last move of black (even without wPe5). Therefore, it does not have the logic of joining the e.p. with castling. For example, ask yourself if black is allowed to castle in the position without wPe5. (2019-08-30)
A.Buchanan: Hi Ladislav, I still don't understand you. Heresies must be explained extraordinarily carefully :-)
Following the conventions:
(1) Black retains castling rights because we cannot prove that bK or bR ever moved.
(2) If e.p. is now played, then we still require the same castling convention, as bK or bR might have moved earlier in the game.
(3) So the actual execution of the e.p. does not prove anything new about castling.
(4) Hence it is incorrect to say "e.p. [is] proof that black can [castle]".
Which step do you disagree with?
Yes by the convention, Black could castle in the position without wPe5. What does that prove? (2020-10-03)
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Keywords: a posteriori (AP), En passant as key, Castling (sg), Promotion (T), Valladao Task
Genre: h#, Retro
Computer test: Popeye 4.61
FEN: r3k3/2p1p3/2P1P3/2KpP3/8/8/8/8
Reprints: V. Die Schwalbe 33, p. 323, 06/1975
2001 CHM Themes 12/2000
3 Die Schwalbe 215, p. 240, 10/2005
A1 Problemkiste 169 02/2007
14 Die Schwalbe 241, p. 374, 02/2010
Input: Gerd Wilts, 1995-06-03
Last update: Alfred Pfeiffer, 2018-01-03 more...
5 - P0003423
Matti Arvo Myllyniemi
3975 Stella Polaris 01/1971
h#3 (AP)
1. ... g6 2. 0-0 gxf7 3. Kh8 Le5#
1. ... cxb6ep 2. 0-0-0 bxa7 3. Td7 a8=D#
play all play one stop play next play all
Henrik Juel: Analysis
If Black can castle both ways, last move must have been b7-b5
C+ Popeye 4.61 (2020-10-25)
Keywords: a posteriori (AP), En passant as key, Castling (sksg), Promotion (D), Valladao Task
Genre: h#, Retro
FEN: r3k2r/p4p1p/8/KpP2PP1/4PBpP/5pp1/6p1/8
Reprints: Nordisches Turnier 1970-1971
Input: Gerd Wilts, 1995-06-03
Last update: James Malcom, 2020-10-25 more...
6 - P0003781
Imre Sztankovszky
(IX) Problem 29-30 05/1955
1. ... b6 2. Le7 Lxg2+ 3. Kd6 Sxc4#
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Henrik Juel: Black is missing [Lc8], which was captured on c8, and a rook
Last move was not c3xTb4, because sTc4's check is impossible, so White has the move (2020-10-01)
Keywords: No legal last move for White
Genre: h#, Retro
FEN: 8/1p1p4/3br3/pP1k4/KPbp4/pn1p4/qN4p1/3n3B
Input: Gerd Wilts, 1995-06-03
Last update: A.Buchanan, 2020-09-30 more...
7 - P0003788
Zvonimir Hernitz
Vladimir Birek

Problem 41-44 03/1957
1. Preis
15. Thematurnier
(2+8) C+
1. ... ... 2. Th3 f4+ 3. Kf6 f5 4. Kg7 f6+ 5. Kh8 f7 6. Th7 f8=D#
1. ... fxe3 2. Dd4 exd4+ 3. Kd6 dxc5+ 4. Kc7 c6 5. Kb8 c7+ 6. Ka8 c8=D#
play all play one stop play next play all
Autoren Zvonko Hernitz, Zagreb & Vladimir Birek, Rijeka
PR Imre Sztankovszky, Böde
Retro-Patt, Excelsior
TLi entdeckte ein eindeutiges Satzspiel: 1. ... ... 2. Th3 f4+ 3. Kf6 f5 4. Kg7 f6+ 5. Kh8 f7 6. Th7 f8=D# mit Echo in der gegenüberliegenden Ecke!
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Keywords: Echo, Promotion (D), No legal last move for White
Genre: h#, Retro
Computer test: Popeye C-Version 3.52 (2048 KB)
FEN: 8/r7/8/2p1k3/4p3/3qpr2/4pP2/4K3
Input: Gerd Wilts, 1995-06-03
Last update: A.Buchanan, 2020-10-01 more...
8 - P0003789
Zvonimir Hernitz
Problem 41-44 03/1957
1. ehrende Erwähnung e.a.
15. Thematurnier
(3+13) C+
1. ... exd7 2. Tfe7 d8=T 3. Te6 Tf8#
1. Sc7? e7 Se6 e8=S# (but Wh to move)
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Autor Zvonko Hernitz, Zagreb
A.Buchanan: So what's the tourney theme exactly? Is it just the wonderful Art.15, the "official joke". There is a unique h#2 retro try: is that a requirement of this tourney? (2020-05-10)
Henrik Juel: You can find the award here, Andrew
on p.79
My Serbo-Croatian is a bit rusty, so I will leave the translation to you (2020-05-10)
A.Buchanan: I cannot see the logic behind sBc4d3g5. The solution, the h#2 retro try, and the retro logic are all unaffected by their removal. There are numerous h#3 tries anyway.
I have found the results of this tourney on pages 79-81 of the document above. At 70 pages, it is too long for google translate, but apparently one can do character recognition in google drive for free, and then those pages might be translatable. There is also an interesting article by Fabel at the beginning about conventions, which might be worth resuscitating. I will leave these for someone else.
This document has been photocopied multiple times, and some of the diagrams are very difficult to read. It makes me never want to compose with a black piece on a black square ever again! However the retro condition makes it easier to reconstruct the diagrams. (2020-09-30)
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Keywords: Promotion (T), No legal last move for White, under-promotion
Genre: h#, Retro
Computer test: Henrik Juel: C+ by Popeye 4.61 (2020-05-10)
FEN: 8/3p1rp1/3PPk2/2pnrbpK/2p1q2b/3p4/8/8
Input: Gerd Wilts, 1995-06-03
Last update: A.Buchanan, 2020-10-01 more...
9 - P0005327
Valerian Onitiu
8397 The Fairy Chess Review 9 28/11/1949
BP in 19,0
Die PAS wurde verändert, indem die Position der schwarzen und weißen Steine geändert wurde (Free Chess).
PAS: ssltktdl, LDTKTLSS (nnbrkrqb/pppppppp/8/8/8/8/PPPPPPPP/BQRKRBNN)
1. b3 0-0-0 (Kf8, Te8) 2. Lf6 gxf6 3. Sg3 Lg7 4. Se4 Lh6 5. Sc5 Le3 6. Sa6 Lb6 7. e3 Dg3 8. Lc4 Dd6 9. Le6 fxe6 10. Sf3 Kf7 11. 0-0 (Kg1,Tef1) Tg8 12. Tce1 Tg3 13. Dd1 Th3 14. g4 Tg8 15. Kg2 Tg5 16. Th1 Tb5 17. Sg5 Kg7 18. Df3 La5 19. Te2 Tb6
play all play one stop play next play all
Originalforderung: "In No. 8397 pieces began game on normal ranks, but not in normal array. The two arrays were however similar, e.g., similar pieces were on c1 and f8. Black has just played his 19th move. What was the game?"
Mario Richter: I do not understand, why 1. ... (Kf8, Te8) is noticed as "0-0-0" (does "Free Chess" have a "Free Castling Rule"?) (2020-09-20)
Keywords: Unique Proof Game, Castling
Genre: Retro
FEN: nnb5/ppppp2p/Nr1qppk1/b5N1/6P1/1P2PQ1r/P1PPRPKP/7R
Input: Gerd Wilts, 1995-06-03
Last update: Mario Richter, 2020-09-20 more...
10 - P0006242
Harold Holgate Cross
5553 FEENSCHACH 09-10/1961
b) Be2 nach e3
Mario Richter: vgl. P1011972 (dort sLa3 statt sTa3) (2020-09-23)
Keywords: Castling, Non-standard material
Genre: Retro
FEN: 8/2ppp2p/1p6/1p6/brPN4/rqP3PP/nbrPPP1r/RNk1K2R
Input: Gerd Wilts, 1995-08-14
Last update: Gerd Wilts, 2004-09-12 more...
11 - P0008793
Andrej N. Kornilow
Shakhmaty v SSSR 1978
1. Ta1-d1+? (Completing the castling!)
a) 1. ... Td4 2. Txd4#
0) 1. xc5ep+? (Completing en passant!)
b) 1. ... Tb5 2. Txb5#
0) 1. xe8=S+? (Completing the promotion!)
c) 1. ... e6 2. Sf6#

0) 1. Sxe7+! Lxe7 2. f8=B# (Omitting the promotion!)
play all play one stop play next play all
Henrik Juel: Completing the key isn't legal, 1.'Rd1'/'-bPc5'/'e8S'+, but omitting the promotion in the mating move is, 1.Sxe7+ Bxe7 2.'f8'#. Excellent joke. (2003-09-19)
James Malcom: A very witty joke Valladao! (2020-09-24)
A.Buchanan: Really like this joke (2020-09-25)
Henrik Juel: To see the illegality of completing 1.fxe8=S+?, note the captures:
Black captured fxDe, so [Pg7,h7] were captured on their files, while the other six missing black men were captured by white pawns
The illegality of completing 1.0-0-0,bxc6ep? is rather obvious (2020-09-26)
James Malcom: And for those you don't find it obvious: If the White king hasn't moved, then where did wRa5, and wBb8 if bPb5 has just done a double-step, come from? Neither can be promoted pieces, as White still has all eight pawns. Trying to finish castling and en passant therefore both produce illegal positions and thus cannot be the solution. (2020-09-26)
Henrik Juel: Continuing beating the dead horse...
How does the white player actually perform an entire move?
1.0-0-0+: Ke1-c1 and Ta1-d1
1.bxc6ep+: Pb5-c6 and remove sPc5
1.fxe8=S+: remove sYe8 and Pf7-e8 and replace wPe8 with wSe8 (three fractional actions)
2.f8=Y#: Pf7-f8 and replace wPf8 with wYf8
So a marginally better stipulation might be: 'White to move mates in less than 2 moves' (2020-09-26)
A.Buchanan: I've tried to set up some intermediate diagrams to allow us to show the animation, but the pieces seem to move even for words which are not moves (and marked italic/red). It's quite baffling. It's almost as if someone with privilege has gone in the background and assigned moves to those dead words. If so, that's extremely unhelpful. Gerd was quite active on this site for a month in German lockdown, for which I'm grateful, but one key task is still waiting: to empower the editors by documenting exactly how the animation decides what to do based on the diagram(s) and stipulation. (2020-09-27)
A.Buchanan: The PDB stipulation field should be non-text form to drive the animation. Where the stipulation is non-standard, there should be a Unicode representation of the original, and translations into German, English and French. But cannot overwrite any original non-standard stipulation, in my opinion, as it is part of the composer's work. (2020-09-27)
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Keywords: En passant, Halber Zug, Castling, Promotion, Valladao Task (half!), Joke, Dummy Pawn
Genre: Retro, n#
FEN: 1B1N1bB1/p2ppP2/2P5/R1pk1N2/1r2p3/1P2P1P1/4PP1P/R1K5
Reprints: (III) Quartz 4 1997
Input: Gerd Wilts, 1997-06-21
Last update: A.Buchanan, 2020-09-27 more...
12 - P0510541
Dragomir Rusin
Problem 41-44 03/1957
3. Preis
15. Thematurnier
(3+14) cooked
1. ... Txg7 2. Td3 Txg6 3. Sd4 Txg4 4. Sb3 Ta4#
play all play one stop play next play all
Cook: NL
1. ... Txg7 2. Ka1 Txf7 3. Sg3 Tf2 4. Dc8 Lxd4#
Yuri Bilokin: Correction: 4nrRB/2p2pbK/p3p1p1/5n2/3r2q1/5p2/k7/1b6 (3+14) (2019-01-19)
A.Buchanan: The diagram matches the published one (2020-10-01)
A.Buchanan: Yuri’s correction is sound and seems economical (2020-10-01)
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Keywords: Check Protection, No legal last move for White
Genre: h#, Retro
FEN: 5rRB/pp2ppbK/2pp2p1/5n2/3r2q1/8/k7/1b6
Input: Markus Manhart, 1997-06-26
Last update: A.Buchanan, 2020-10-01 more...
13 - P1000901
Tomislav Petrovic
3 feenschach 137, p. 340, 08-09/2000
Zdravko Maslar gewidmet
(14+8) C+
1. dxc6ep!
1. ... dxc6+ 2. Lxc6 Sc7#
1. ... d6 2. d5 Sc7#
1. ... d5 2. exd5 Sc7#
1. ... dxe6 2. e5 Sc7#
1. ... gxf6 2. Sf5 Sc7#
1. ... g6 2. Lxg6 Sc7#
1. ... g5 2. Sg4 Sc7#
1. ... gxh6 2. Lh5 Sc7#
play all play one stop play next play all
James Malcom: This is a most excellent problem! En passant as the key and a double pickaninny in a short s#2 is surely no easy feat, I'd say. Now, question: Why can't dxc5 be Black's last move? The illegal retraction od b6-b7 is already quite obvious. (2020-10-24)
A.Buchanan: R: 1. cxb6/dxc5? both imply 3 pawn captures by Bl (2020-10-24)
A.Buchanan: I agree this is a beautifully integrated composition (2020-10-24)
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Keywords: En passant, Pickaninny (2x), En passant as key, grab
Genre: Retro, s#
Computer test: C+ Popeye 4.61 after retro-analysis shows that last move was c7-c5
FEN: n2RB3/k2p2pR/Pp2PP1N/bKpP4/PpNPP3/1P6/8/8
Input: Gerd Wilts, 2000-10-08
Last update: A.Buchanan, 2020-10-25 more...
14 - P1000957
Thierry Le Gleuher
10c Messigny 2000
BP in 20,5
1. h4 e6 2. Th3 Ld6 3. Te3 Lg3 4. Te5 d6 5. e4 Ld7 6. Lc4 Lb5 7. Ld5 Lf1 8. d3 h6 9. Lg5 hxg5 10. c4 Th6 11. Sc3 Tf6 12. Db1 Tf3 13. Kd1 Te3 14. f4 Te2 15. f5 Tc2 16. Sce2 Tc3 17. f6 Tb3 18. axb3 c5 19. Ta6 Da5 20. b4 Kd8 21. bxa5
play all play one stop play next play all
Lange Wanderung des sTh8 nach b3. Der wBa muss überkreuz geschlagen haben, damit Weiß den wTa1 schnell genug nach a6 spielen kann.
Michel Caillaud: cooked testing the last moves with Jacobi 0.7.5 and constraints for wBa cross-capture
(constraints Pa2-a3xb4xa5 or Pa2xb3-b4xa5 or Pa2xb3xa4-a5) :
9…c5 10.Cc3 Dd7 11.Cce2 Cf6 12.Db1 Re7 13.Rd1 Tc8 14.c4 Tc6 15.f4 Tb6 16.f5 Tb3 17.axb3 hxg5 18.Ta6 Da4 19.bxa4 Rd8 20.a5 Cg8 21.f6 (2020-10-17)
Keywords: Unique Proof Game, Promenade
Genre: Retro
FEN: rn1k2n1/pp3pp1/R2ppP2/P1pBR1p1/2P1P2P/3P2b1/1P2N1P1/1Q1K1bN1
Input: Gerd Wilts, 2000-10-15
Last update: Gerd Wilts, 2005-12-30 more...
15 - P1001097
Michel Caillaud
R121 Probleemblad 01/2001
Special Prize 2001
(12+13) C+
1. cxb6 d6 2. bxc5 Txb8#
1. La7 Lxa7 2. 0-0-0? Tb8#
play all play one stop play next play all
Castling is impossible because, if black can still castle, the diagram position is draw due to the 50-move rule!
White captures: axb, bxc, exf. Black captures: hxg, gxf, exd, dxc. Promotions: a1=T, b1=T, h8=X. The position can only be unblocked by unpromoting White piece on h8. This can only be wRb5. wK must go to c6 to unpin wR. The journey is via g3, h2, e1, b2, & a3.The 50 white moves are: 34 by wK (screens on c8 [with careful step on a2 to let bB pass] then g8), 11 by wB6 (to e3 to exchange place with bB then screen on a7), 3 by wR (promotion on h8), 2 by wBa4.
more ...
Keywords: Non-standard material (tt), 50 move rule, Cant Castler
Genre: Retro, h#
Computer test: Popeye WINDOWS-32Bit-Version 3.65 (2048 KB) Popeye 4.61 (also)
FEN: rb2k3/2p2p1K/1B6/1RPP1PP1/B1Prbrp1/1Prp1p2/2p2P2/N7
Reprints: Probleemblad , p. 220-227, 12/2010
Input: Gerd Wilts, 2001-02-11
Last update: A.Buchanan, 2020-10-10 more...
16 - P1011972
Harold Holgate Cross
Die Schwalbe 1961
b) wBe2 nach e3
a) 1. 0-0#
R: 1. Tg2-h2 Sf5-d4 2. Th2-g2 Se3-f5 3. Tg2-h2 Sf1-e3 4. Tg1-g2 Se3-f1 5. g2-g1=T ... 6. f3xDg2 ... 7. f4-f3 Da8-g2 8. f5-f4 a7-a8=D 9. f6-f5 a6-a7 10. f7-f6 a5-a6 11. a6xLb5 Lc6-b5 12. Lb5-a4
b) 1. Se2#
play all play one stop play next play all
No. 1039 HN
Mario Richter: vgl. P0006242 (dort sTa3 statt sLa3) (2020-09-23)
Henrik Juel: White captured bxc and promoted on a8
Black captured axb and promoted twice on g1: f3xg2-g1=T, g3xh2xg1=L
In part b) the castling right cannot be preserved, because the tempo is wrong (2020-09-23)
Keywords: Cant Castler, Castling
Genre: Retro
FEN: 8/2ppp2p/1p6/1p6/brPN4/bqP3PP/nbrPPP1r/RNk1K2R
Input: Henri Nouguier, 2004-01-11
Last update: Mario Richter, 2020-09-23 more...
17 - P1012843
Iosif Schlarko
1171 Funkschach 13/03/1927
(12+13) cooked
Weiß nimmt 1 Zug zurück, dann s#1
R: 1. Td1-a1 dann 1. Td4+! Tc4#
R: 1. Td1-a1 f3-f2 2. Ta1-d1 f4-f3 3. Lc1-e3 f5-f4 4. d2xSc3 Sd1-c3 5. Tb1-a1 Sf2-d1 6. Ta1-b1 Sh1-f2 7. Tb1-a1 Sf2xTh1! 8. Ta1-b1 Se4-f2 9. Tb1-a1 Sc5-e4 10. Ta1-b1 Sb3-c5 11. Tb1-a1 Sa1-b3! 12. Tg1-h1! a2-a1=S 13. Ta1-b1 b3xDa2 14. Th1-g1 b4-b3 15. Dd5-a2 b5-b4 16. a2-a3 a6xSb5 etc.
play all play one stop play next play all
No. 715 HN
Mario Richter: Stellung ist inkorrekt (8 wBB + wUW-L), und die angegebene Lösung paßt auch nicht zu Stellung+Forderung. (2010-01-05)
A.Buchanan: OK there were numerous typos in both the diagram and Henri's solution - which is visible only in edit mode, but it did show the intended plan, and I think I've succeeded in correcting them both. If someone can find Funkschach to check, I would appreciate. This is a nice problem for its time and well worth salvaging. (2020-09-19)
Henrik Juel: Nice that 4.d2xSc3 and 13... b3xDa2 are the only possible uncaptures (2020-09-19)
Mario Richter: Sorry, Henrik, but unless the position is still incorrect, the problem is cooked: there's no need for an unpromotion on a1 and the earlier uncapture of Rook h1 (which would be necessary to provide a tempo move after 11. Sa1-b3):
wCaps: d2xBc3 g6xSh7 f3xSg4
sCaps: a6xSb5xSc4, c7xDd6 and (e.g.) Db6xTg1
R: 1. Td1-a1 f3-f2 2. Ta1-d1 f4-f3 3. Lc1-e3 f5-f4 4. d2xBc3! c4-c3 5. a2-a3 Kb4-a4 6. Tb1-a1 b5xSc4 and so on (2020-09-20)
Henrik Juel: You are right, Mario
The problem is cooked (2020-09-20)
A.Buchanan: Can we have wBc3 to e3, removing wLe3 and sBf2. Add sTe1. Yes there is non-standard material but can work on that. Is it sound? (2020-09-20)
Mario Richter: Yes Andrew, your Suggestion (wBc3 to e3, removing wLe3 and sBf2. Add sTe1) makes the Problem correct. With a white double pawn on the e-file the uncapture of a black pawn is impossible (d2xBauer_e3??), so only the intended solution works! (2020-09-20)
Mario Richter: Re-checking Andrew's correction, I have to correct myself: the problem is still cooked:
wPawnCaps: g6xSh7 d2xLe3 f3xSg4
sPawnCaps: b3xDa2 a5xLb4 f2xTg1=L c7xSd6
sProms: a2-a1=T f2xTg1=L
R: 1. Td1-a1 Tc4xSc7! 2. Td2-d1 Ta1-e1 3. Td1-d2 a2-a1=T 4. Ta1-d1 b3xDa2 5. Db1-a2 b4-b3 6. Dd1-b1 a5xLb4 7. Ld2-b4 Tf4-c4 8. a2-a3 Kb4-a4 9. Lc1-d2 Kc4-b4 10. Tb1-a1 a6-a5 11. Ka5-b6 Da7-a8 12. Ta1-b1 Dd4-a7 13. Ka4-a5 Dh8-d4 14. Sb5-c7 Lb6-d8 15. Sc3-b5 Dd8-h8 16. Sb1-c3 Tf8-f4 17. d2xLe3 Kd5-c4 18. Kb3-a4 Lg1-e3 19. Kc3-b3 f2xTg1=L! (2020-09-23)
A.Buchanan: Well done Mario! Have to say I didn't like my repair so much because of the retro dual R: 1. Ta1-a1 fxLe1=T 2. Le2-e1,Ta1-d1. (2020-09-23)
more ...
Keywords: Help retractor
Genre: Retro
FEN: qrbb4/1prpp2P/1K1p2pp/8/k7/P1P1B3/1PP1PpPP/R4B2
Input: Henri Nouguier, 2004-01-11
Last update: James Malcom, 2020-09-20 more...
18 - P1186997
Erich Bartel
5552 Problemkiste (138) 12/2001
(4+4) C+
h=3 (AP)
1. ... hxg6ep 2. 0-0 g7 3. Kh7 gxf8=D=
play all play one stop play next play all
Wenn ep erlaubt sein soll, dann muß g7-g5 der letzte Zug gewesen sein. Dies wiederum bedingt, daß sK+sT noch nicht gezogen haben. Nur unter dieser Betrachtungsweise (AP) ist das Ding korrekt.\eb
Diese AP-Idee ist ja nun hinlänglich bekannt, aber man muß auch darauf kommen, sie für den Valladao zu nutzen. Finde ich prima (MN).
ep, und dann kann Schwarz auch noch rochieren (HM).
Wenn g7-g5 letzter Zug war, darf Schwarz noch rochieren (KF)...
AP (= a posteriori) argumentiert andersrum: wenn Schwarz noch soll rochieren dürfen, muß g7-g5 der letzte schwarze Zug gewesen sein (\eb)
Unlösbar! Der Autor meint wohl, man könnte mit 1. ... hxg6ep 2. 0-0 loslegen; hier irrt Goethe. Die beiden Konventionen -ep-Schlag nur, wenn Zulässigkeit retroanalytisch beweisbar ist; Rochade stets, außer wenn Unzulässigkeit retroanalytisch beweisbar ist- sind zwar passend verknüpft. Was aber den Vorrang hat, zeigt die zeitlich Reihenfolge der Anwendung. Zuerst kommt der ep-Schlag, und diesbezüglich gilt: Zulässigkeit nicht beweisbar, also nicht erlaubt (LZ).
Lieber Herr Zagler, vielen Dank für Ihren Kommentar, aber ich denke nicht, daß dazu eine Stellungnahme erforderlich ist, denn dazu ist schon viel diskutiert und geschrieben worden, ichverweise nur auf G. Lauingers "a posteriori Zwischenbilanz" in feenschach (80) X-XI 1986, S.414 ff, wo die AP-Regelung allgemein wie folgt definiert wurde:
"Eine einleitende Handlung (z.B. ein ep-Schlag oder ein unkonventionell Beginn), deren Zulässigkeit nach gültigen Konventionen zunächst nicht nachgewiesen werden kann, wird im Verlauf der Lösung(en) nachträglich durch einen oder mehrere Sonderzüge legalisiert. Legalisieren bedeutet dabei, daß _nur_mit_der_Ausführung_ des Sonderzuges (der Sonderzüge) dessen (deren) Zulässigkeit nachgewiesen wird und gleichzeitig (i.a. aus retroanalytischen Gründen) damit auch nachträglich die Zulässigkeit der einleitenden Handlung."
Ob Sie nun mit dieser Regelung einverstanden sind hat für o.a. Aufgabe wenig Bedeutung, denn nach o.a. "AP"-Definition ist sie lösbar. Wenn Sie "AP" so nicht akzeptieren und einer anderen Retro-Philosophie zugetan sind, steht das auf einem anderen Blatt. Da müßten Sie sich dann mit den entsprechenden Experten auseinandersetzen. (\eb)
Da nur die Rochade den sK nach h7 zu manövrieren vermag, fällt manchem sicher gar nicht erst auf, daß allein sie (neben dem Autor, natürlich!) für die Legalisierung des e.p.-Schlages verantwortlich ist (MR).
Valladao-Task. Bei dieser Ausgangsstellung mit Ansage (HL).
A.Buchanan: Removing the superfluous sBf7 adds various non-castling lines which the AP convention duly protects us from, and makes the composition a sound miniature (2020-10-03)
Keywords: Valladao Task, Castling, En passant, Promotion, a posteriori (AP)
Genre: Retro
Computer test: %Popeye FreeBSD-4.3-RELEASE-32Bit-Version 3.73
FEN: 4k2r/5p2/5P1P/5KpP/8/8/8/8
Reprints: Springaren (116) 03/2010
K3966 Problemkiste (199/200) 03/2012
Input: Erich Bartel, 2011-02-09
Last update: Alfred Pfeiffer, 2014-09-05 more...
19 - P1260207
Charles Henry Wheeler
892 Dubuque Chess Journal 05/1874
s# in wieviel Zügen?
1) R: 1. ... 0-0-0, dann 1. Txg6#
2) R: 1. ... 0-0-0, dann 1. Df7#
play all play one stop play next play all
Weiß kann Selbstmatt ohne einen eigenen Zug erzwingen.
Schwarz rochierte im letzten Zug, obwohl er im Schachstand und ignorierte dabei auch das Schach auf d8. Beides ist illegal. Er muss diesen Zug zurücknehmen und statt dessen Df7# oder Txg6# spielen.
A.Buchanan: No retro analysis to show that last move was in fact castling. Position is not illegal. (2019-10-21)
James Malcom: Perhaps that's why it labeled as a joke then. Andrew. (2020-10-20)
A.Buchanan: Yes it’s a joke but there is an existing species of problem where the position Is illegal. This is kind of like Conan Doyle vs Agatha Christie: here we are only told the key clue after the fact. I am sadly interested in classifying the main families of jokes, identifying which ones are fairies as well etc. This one is not fairy I think. In constraint promotion into foreign units can be joke depending on stipulation, but is definitely fairy (2020-10-21)
Keywords: Joke, Retract illegal move (castling)
Genre: s#, Retro
FEN: 2kr1b2/p3p3/4K1Br/B3R3/8/5q2/8/8
Input: Frank Müller, 2013-01-19
Last update: Alfred Pfeiffer, 2019-10-22 more...
20 - P1288715
Bernd Schwarzkopf
A12 Problemkiste (169) 02/2007
(4+3) C+
1. dxc6ep 0-0-0 2. b7+ Kb8 3. c7+ Kxb7 4. cxd8=D Ka7 5. Dc8=
3. ... Ka7 4. cxd8=S Kb8 5. Ka6,Kb6=
play all play one stop play next play all
A.Buchanan: Guessing so-called "AP-Priorität" is a variant of AP whereby Black is forced to legitimize (or at least forbidden to rule out the possibility of legitimizing) the earlier e.p. (2020-10-03)
Keywords: En passant, a posteriori (AP), Castling, En passant as key, Promotion, Valladao Task
Genre: Retro, Fairies
Computer test: Popeye v4.85 + minor retro/AP thinking
FEN: r3k3/8/1P1P4/1KpP4/8/8/8/8
Input: Erich Bartel, 2014-09-29
Last update: A.Buchanan, 2020-10-03 more...
21 - P1305230
Thierry Le Gleuher
1 RIFACE 2015
Ajouter des pièces.
+wSb2d2 +wLc4
R: 1. Dd1-c2+ Kc2-c3 etc
play all play one stop play next play all
A.Buchanan: How about wLa1 instead? (2020-10-06)
Henrik Juel: Yes, that would improve the economy slightly (2020-10-06)
Ladislav Packa: wBa1 is illegal... (2020-10-07)
A.Buchanan: Hi Ladislav why is wLa1 illegal, please? That was essentially my question before (2020-10-07)
Mario Richter: wLa1 instead of wDa1 is of course legal too: one of the dark-squared wBishops unpromotes on h8, one wQueen on g8. Black pawns g7+h7 let the wPawns g2+h2 pass by cross-capturing the 2 original wRooks. (2020-10-07)
more ...
Keywords: Add pieces, Illegal position
Genre: Retro
FEN: 8/P7/P7/P1Q5/P3K3/P1k5/P1Q5/Q3B3
Input: A.Buchanan, 2015-07-08
Last update: A.Buchanan, 2020-10-07 more...
22 - P1338394
Göran Wicklund
J.Lois-70 JT 2016-2017
2nd Honorable Mention
(12+14) cooked
PG in 33.0
1. Sf3 a5 2. Sd4 a4 3. Sb3 axb3 4. a4 Ta5 5. Ta2 bxa2 6. h4 a1=S 7. h5 Sb3 8. h6 Sd4 9. hxg7 Sf5 10. gxh8=L Sh4 11. Le5 f5 12. Lh2 e5 13. g3 La3 14. Lg2 Se7 15. Lc6 dxc6 16. 0-0 Sd7 17. Kh1 Sf8 18. Lg1 Dd5+ 19. Kh2 Kd7 20. Kh3 Dh1+ 21. Lh2 e4 22. Tg1 Te5 23. Df1 c5 24. Dg2 Kc6 25. Df3 Kb6 26. Tg2 Dd1 27. Tg1 Ka5 28. Te1 b6 29. Lg1 La6 30. Kh2 Ld3 31. Kh1 c4 32. Lh2 c5 33. Kg1 Dxe1#
play all play one stop play next play all
Judge J. Lois: This problem presents the theme Lois between the wK1-WBh2(2) with a switchback of both pieces.
In addition, change of place between WKe1-wRh1 in move 31.
Henrik Juel: In the award this proof game is not labelled C+ (2017-08-30)
Michel Caillaud: reported as cooked in Winchloé :
1.a4 b5 2.Ta3 b4 3.h4 bxa3 4.h5 a2 5.h6 a1=S 6.hxg7 Sb3 7.gxh8=L Sd4 8.Le5 Sf5 9.Lh2 e5 10.g3 La3 11.Lg2 La6 12.Lc6 dxc6 13.Kf1 c5 14.Kg2 Kd7 15.Sh3 Kc6 16.Sf4 Kb6 17.Sd5+ Ka5 18.Sb6 axb6 19.Kh3 Dd5 20.Tg1 Dh1 21.Df1 e4 22.Dg2 Sd7 23.Df3 Te8 24.Tg2 Dd1 25.Tg1 Te5 26.Te1 Sf8 27.Lg1 Sge7 28.Lh2 Sh4 29.Lg1 f5… (2020-10-14)
more ...
Keywords: Unique Proof Game, Non-standard material, Lois Theme
Genre: Retro
FEN: 5n2/4n2p/1p6/k1p1rp2/P1p1p2n/b2b1QP1/1PPPPP1B/1NB1q1K1
Input: A.Buchanan, 2017-08-30
Last update: A.Buchanan, 2020-10-15 more...
23 - P1360119
Marken Foo
www.chess.com 2016
PG in 7.0 moves
Add the black queen
b) +wSb1
Marken Foo: There is a twin (b) +wSb1 pointed out by the chess.com user caveatcanis back in 2016, when accidentally misreading the diagram. It turns out to be a cute twin that fits the idea. (2020-10-21)
A.Buchanan: How many of these "Where in the world is Carmen Sandiego?" problems have you got, Marken? is it worth making a keyword? https://en.wikipedia.org/wiki/Carmen_Sandiego (2020-10-21)
Keywords: Unique Proof Game, Add pieces (d)
Genre: Retro
FEN: rnbN1knr/pppppp2/8/8/8/8/PPPPPPP1/R1BQKB1R
Reprints: 9 Phénix 287, p. 11252, 07-08/2018
Input: A.Buchanan, 2019-01-25
Last update: A.Buchanan, 2020-10-21 more...
24 - P1368554
Andrew Buchanan
OzProblems.com 16/10/2019
(4+3) C+
1. Sd3! Kf8 2. Se3 Sg6+ 3. Kd4 Td8+ 4. Kc3 Tc8+ 5. Sc4 Kg7 6. Sf2 Sh8 7. Tf1 Sf7 8. Se4 Td8 9. Sf6 Sg5 10. Se3 Ta8 11. Kb4 Tb8+ 12. Kc4 Tc8+ 13. Kb5 Tb8+ 14. Kc6 Ta8 15. Sfd5 Ta3 16. Kb5 Se4 17. Te1 Sg5 18. Kb4 Ta2 19. Tf1 Kg6 20. Tf6+ Kh5 21. Kb3 Ta7 22. Sf4+ Kh4 23. Se2 Tb7+ 24. Kc4 Sf7 25. Tf1 Kg5 26. Sd4 Se5+ 27. Kd5 Sd3 28. Se6+ Kg6 29. Sf8+ Kg5 30. Ke4 Sc5+ 31. Kd4 Sd7 32. Se6+ Kg6 33. Sd5 Ta7 34. Se7+ Kh5 35. Tg1 Ta4+ 36. Ke3 Tg4 37. Ta1 Sb6 38. Kf2 Sd7 39. Ta8 Tc4 40. Tg8 Tc2+ 41. Ke3 Tc3+ 42. Kf4 Tc4+ 43. Kf5 Kh4 44. Sf4 Tc5+ 45. Sed5 Txd5+ 46. Sxd5 Kh3 47. Tc8 Kg3 48. Ke6 Sb6 49. Sxb6 Kf2 50. Sc4 Ke1 51. Td8 Ke2 52. Td2+ Ke1 53. Kd5 Kf1 54. Ke4 Kg1 55. Kf3 Kh1 56. Kg3 Kg1 57. Td1#
play all play one stop play next play all
According to the Syzygy tablebase, *any* move wins for White except the silly 1. Sa2??
However, the tablebase does not know about castling!
The quickest winning move 1. Sd3!? would be defeated by 1. ... 0-0-0!? which attacks Sd3 and threatens the skewer Re8+. After this, White can only draw - or even loses after 2. Sc1??
But by a simple retro argument, Black cannot castle.
Since this retro point is essential to the solution, we have a retro problem, and hence the 50 move rule, which by Codex default is disengaged, is switched on.
When working with the 50 move rule, the key concept is not the number of moves to mate, but the number of moves to the first capture, pawn move or checkmate, known as DTZ.
All the alternatives to 1. Sd3 take more than 50 moves to force the first capture. The closest are 1. Sc3 & Se3 which according to Syzygy require exactly 50.5 moves, so seem *just* too slow. (For positions close to the cut-off, one has to be careful about *rounding*, see https://syzygy-tables.info/metrics. The number of half-moves for DTZ can be n or n+1. In fact here, after 1. Sc3/Sf3, the zeroing move is at its earliest White's 52nd move, not 51st.)
By the retro property therefore *only* 1. Sd3!, which requires 45 moves to force the first capture, can win. So this removes all the cooks for the first White move.

Lomonosov DTM #59: 1. Nd3!! Kf8!! 2. Ne3! Ng6+! 3. Kd5 Rd8+ 4. Kc4 Rc8+ 5. Kb5 Rb8+ 6. Ka6 Kf7 7. Nc5 Ne5 8. Nd5 Re8 9. Kb7 Nc4 10. Rf1+ Kg7 11. Kc6 Re5 12. Nd3 Re6+ 13. Kc5 Ne5 14. N3f4 Nd7+ 15. Kb5 Rd6 16. Nc7 Kf7 17. Nfd5+ Kg6 18. Ne7+ Kg5 19. Ncd5 Kg4 20. Rf4+ Kg5 21. Rf2 Kg4 22. Ne3+ Kg5 23. N7d5 Kg6 24. Rf1 Nf6 25. Nf4+ Kf7 26. Nc4 Rd8 27. Ne5+ Kg8 28. Rg1+ Kh7 29. Kc6 Rc8+ 30. Kd6 Re8 31. Re1 Ra8 32. Rh1+ Kg8 33. Ke7 Ra4 34. Rg1+ Kh7 35. Ne6 Nd5+ 36. Kd6 Nf4 37. Nc5 Rd4+ 38. Ke7 Rd2 39. Rg4 Rf2 40. Ncd7 Nd5+ 41. Ke6 Nf4+ 42. Kd6 Rd2+ 43. Ke7 Nd5+ 44. Kf8 Kh6 45. Rh4+ Kg5 46. Nf3+ Kf5 47. Nxd2 (zeroing 50M) Nc7 48. Re4 Ne6+ 49. Ke7 Nf4 50. Nf6 Ng6+ 51. Kf7 Ne5+ 52. Kg7 Kg5 53. Nf1 Kf5 54. Ne3+ Ke6 55. Nc4 Ke7 56. Rxe5+ Kd8 57. Rc5 Ke7 58. Rd5 Ke6 59. Re5# 1-0.

The school shield which inspired the problem:
Henrik Juel: With White to move, last move was made with Ta8 or Ke8, so Black may not castle
An endgame connaisseur may supply the solution... (2019-10-25)
James Malcom: It is now supplied, Henrik. :) I worked through the Sygyzy tablebase, move by move, to get the computer recommended line. (2020-10-09)
A.Buchanan: Thanks James for this hard work to record a solution. Alas there is not just a single recommended line - White has a choice as early as W3. I wonder too if there is a DTM line which is faster than #57, and still clears the DTZ hurdle although maybe not as quickly as B45 as here. There is no DTM engines for 7 pieces yet.
What is certain is that the key works, and is unique. The exactly details of the best mating line remain to be revealed by improving technology. (2020-10-09)
A.Buchanan: For example, 2. Nc5 has DTZ 90, compared to the "superior" 2. Ne3 DTZ 88. However, if you keep picking the top move all the way through, then the final DTZ is in fact checkmate! I haven't all the Black choices though, but there aren't that many of them (2020-10-09)
A.Buchanan: The Lomonosov tablebase is DTM, and is available for free on Android. Today I found a PC app called Blue Stacks which emulates Android. According to Lomonosov, the position is #59, compared to Syzygy's DTZ offering #57 via zero at B45. When I run through the L. indicative solution (very quick to download and grab all of it), it is close to S.'s choices and all the mainline positions are safe from 50M. The zero is at W47, and the final mate is attractive in the middle of the board.
The real questions are:
(1) Is the #59 sound from 50M perspective? Or can Black force White to delay a few moves in order to avoid 50M trouble somewhere?
(2) How dualized is the solution? How does 50M play into pruning that?
What is clear is that both tablebases agree the solution begins 1. Nd3!! Kf8!! 2. Ne3! Ng6! (2020-10-10)
Keywords: Cant Castler, Aristocrat, 50 move rule, Miniature
Genre: Retro, Studies
Computer test: www.syzygy.com
FEN: r3k2n/8/8/4K3/8/8/8/2NNR3
Reprints: www.chess.com 17/10/2019
Input: A.Buchanan, 2019-10-25
Last update: A.Buchanan, 2020-10-10 more...
25 - P1375286
Andrew Buchanan
James Malcom

PDB Website 30/4/2020
1. dxc7ep! b4 2. c8=D,T#

R: 1. ... c8-c6?! and earlier c8=sB
play all play one stop play next play all
Superseded by P1380851

Related: http://www.matplus.net/start.php?px=1577108437&app=forum&act=posts&fid=xshow2&tid=2395

The 2018 FIDE laws state: "3.7.2 on its first move the pawn may move as in 3.7.1 or alternatively it may advance two squares along the same file, provided that both squares are unoccupied."

Hence Black's newborn 8th rank pawn, which has never been moved before, reserves the right to commence a double-step on its first move, and likewise White receives the right to capture it en passant as they do with a 7th rank pawn.
Henrik Juel: This un-dummy-pawn is like a pawn created on c8 by the Einstein condition
The retroplay looks wrong, what about 1... d8-d6!? 2.d7-d8=sB!? c6xYb5 (2020-04-30)
James Malcom: That makes much more sense Henrik. I have edited it accordingly. (2020-04-30)
A.Buchanan: You don't like Adrian's (: haha? What about :) then? In heraldic terms, it would be described as "regardant". See 270 on https://www.heraldica.org/cgi-bin/atlas.pl?12. I don't know the word for "non-regardant", which is the default direction for the head, e.g. most of the others on that page.
We could replace wBa6a7 with wSa6, but alas having the 3rd knight is non-thematic & distracting. The other thing I would've liked to do is empty b2 so the promotion is forced to be to D. Such a tiny problem should have precision promotion. Needs more thinking. (2020-05-01)
James Malcom: UPDATE: The position has been edited to have one less piece and a precise queen promotion. (2020-10-12)
A.Buchanan: There is dialogue here which is now orphaned by a change of diagram with new matrix. Suggest we revert to the older diagram and mark it superseded by a new PDB entry here (2020-10-12)
James Malcom: I agree-it is now done. (2020-10-12)
more ...
Keywords: En passant, En passant as key, Joke, Joke promotion (b), Tolerated dual promotion (D/T), Promotion (D, T), Superseded by (P1380851)
Genre: 2#, Retro
FEN: k7/PN1N4/PKpP4/1p6/8/8/8/8
Input: James Malcom, 2020-04-30
Last update: A.Buchanan, 2020-10-12 more...
26 - P1375497
Iosif Schlarko
Valerian Onitiu

F19 Skakbladet 15, p. 172, 09/1923
(1+11) C+
-1(w+s), dann h#4
R: 1. Ke3xBd3 Be4xd3ep, dann 1. Dg7 dxe5 2. Kh6 exf6 3. g5 fxg7 4. Tg6 gxh8=D#
play all play one stop play next play all
A.Buchanan: Corrected typo: Tf6g6 are really pawns in the skakbladet diagram (2020-09-18)
Mario Richter: also C+ with rawbats (2020-09-20)
Keywords: Help retractor, En passant in the retro play, Promotion in the mating move, Rex solus (w)
Genre: Retro
Computer test: rawbats for retro play ^=& Popeye v4.85 for the forward play
FEN: 7n/q7/2r2pp1/3pr1k1/8/3K1n2/8/3bb3
Input: Mario Richter, 2020-05-04
Last update: A.Buchanan, 2020-09-21 more...
27 - P1375499
Iosif Schlarko
Wolfgang Pauly

F20 Skakbladet 15, p. 172, 09/1923
-3w,2s, dann h#2.5
R: 1. Ke3xBd3 Be4xd3ep 2. Bd2-d4 Dd7-a7+ 3. Kf4-e3 (g7-g5+), dann 1. hxg6ep+ Ke8 2. g7 Te7 3. g8=D#
play all play one stop play next play all
T.R. Dawson zu dieser Aufgabe und P1375497: "Two interesting combinations of retraction play with helpmating; the elementary exhibition of the PxPe.p. retraction, as in these problems, must soon be abandoned however, I think in favour of greater elaborations."

Originalforderung: Hvidhar trukket sidst. 3 Træk tidligere var det muligt, at Hvid ved Sorts Hjælp kunde gøre Mat i 3 Træk. Hvorledes?
Klarstellung Heft 18 (December 1923) S.211: "For ikke at misforstaans, burde Fordringen lyde '3 hvide Træk tidligere' etc. -"
Walter Lindenthal: Wie wäre es mit einer wDa7:
R 1.Ke3xBd3 Be4xd3ep 2.Bd2-d4 Dd7xDa7+ 3.Da~-a7
& vor 1.wDa7-a8 Ke7-f6 2.Da8-g8 Dd7-e7 3.Dg8-g6# (2020-09-15)
Walter Lindenthal: Korrektur Flüchtigkeitsfehler in der NL:
... & vor 1.wDa~-a8 ... (2020-09-16)
A.Buchanan: Yes Walter something not quite right. Maybe wP missing from diagram. But even then g7-g5 is not forced so how is the White e.p. ok? (2020-09-17)
Walter Lindenthal: It's not ok with today's rules! (That's why my solution avoids it). As far as I understand, the ep-rules were handled differently in that time (1923!), ep had not to be 'forced'. As Dawson (above) seems to hint to that fact ("... must soon be abandoned...") (2020-09-17)
Walter Lindenthal: And I do not think a wP (or any other w piece) is missing mistakenly! The idea seems to be that the wK MUST start to retract into fields EACH threatened twice, so only the (first) ep can R-save the wK. And if there is NO additional wP (or a wQ like mine) then again ONLY the wK can retract. And such he is "forced" into the next threat, where the second ep would R-save him again and finally lead to mate. If there is no second ep (old style 1923!) then there's no mate in h#2.5. So, any (rectractable) additonal w piece would destroy this tactic (like my wQa7 does by eliminating the need for wK's move e3-f4 into the second threat from bPg5). The only point is if this additional w piece can establish a different mate in h#2.5 (as my wQ can). (2020-09-17)
A.Buchanan: Hi Walter, thanks for your responses. I checked skakbladet: the diagram, stipulation and intended solution are accurate. However by 1915 (Dawson & Hunsdorfer "Retrograde Analysis" page 111), the notion of analytic en passant was already established. Moreover, the other problem (P1375497) that Dawson apparently mentioned does *not* contain a forward en passant, so I think he was referring to the simplistic retro logic present in both. Maybe Dawson was being polite in his criticism of the unproven forward e.p. here.
So how about the chess? Is Dd7xDa7+ & Kf4-e3 the only retraction which leads to any #2.5? It seems that other retractions might at least be possible: e.g. S~-b3, T~-c4, D~-a7, and any of them could be any uncapture. Maybe I will look at this later, but I must go now. (2020-09-18)
Walter Lindenthal: Hi Andrew, thanks for the clarifying info! So, the "unproven ep"-issue was decided even before 1923 (I just assumed because of Dawson's comment...), but then the problem would have been broken from start! Of course, some other retractions might be possible, too, but I have not analysed any other one if it could lead to a h#2.5 solution. My only intention with wQa7 was to show that the intended solution was not the only one possible, so it's cooked. (2020-09-18)
Mario Richter: The intended solution is the only possible one (checked with 'rawbats'), if we accept that g7-g5 preceeded the other retractions (perhaps the idea was help-play in the retractions).
The suggested R 1.Ke3xBd3 Be4xd3ep 2.Bd2-d4 Dd7xDa7+?? doesn't work (illegal black pawn structure)! (2020-09-20)
Walter Lindenthal: Hi Mario - GREAT, yes, you're right! The bBe1 is the 'killjoy'... 5+7+4=16, there is no room for ANY additional w stone! thanks! (2020-09-21)
Keywords: Help retractor, En passant in the retro play, En passant as key, Promotion in the mating move
Genre: Retro
FEN: 8/q3k3/2p4p/3pr1pP/2r3pp/1n1K4/5P1P/1n1bb3
Input: Mario Richter, 2020-05-04
Last update: A.Buchanan, 2020-09-21 more...
28 - P1375777
James Malcom
PDB Website 10/4/2020
nach Josef Cumpe
Last two moves?
R: 1. 0-0-0# a7-a8=sT
play all play one stop play next play all
See P1234039
Henrik Juel: Missing Joke keyword, I guess (2020-05-11)
A.Buchanan: Curious that retro a7-a8=sT discomforts the animation still - maybe you should report to Gerd? (I trouble him with enough stuff already - don't want to be the only one emailing him! :-) (2020-05-11)
A.Buchanan: Maybe +sBe7f7 to refute R. ... e8=sK/fxe8=sK :-) Note this "cook" is actually prevented in the original. (2020-05-11)
A.Buchanan: Oops and a more major cook R: 1. Se8/g8-f6+ (2020-05-11)
James Malcom: This problem was only half-finished before I fell asleep. It’s fixed now. (2020-05-11)
A.Buchanan: Great! You could save another piece I think -sLg6, -sBf7, + sDf7. This also removes the obtrusive promotion (2020-05-11)
James Malcom: Yes, that is true. Position edited. (2020-05-11)
James Malcom: I see nothing wrong with fiddling if it improves economy. (2020-05-11)
A.Buchanan: If promotion to Bl unit is allowed, can’t Bl just have played e8xd7+ or g8xh7+? Can replace bPd7 with bR but eliminating bPh7 is more complicated. Need +wPh7 +bPg6h6. And also bRb7 to prevent discovered check by bPc8 prior to e7-e8=bK. I think that’s watertight now! :-) (2020-10-13)
A.Buchanan: The issue is that there are two or three levels of Bl promotion joke: this problem relies on the "basic" joke where black officers can be created. But where's the line to stop us promoting to Bl pawn or king? If we go that far, then a position like this 2kr3K/1r1r1qrR/7p/8/8/8/8/8 is required. Oh dear: sorry to have brought it up :( (2020-10-13)
more ...
Keywords: Castling in the retro play, Promotion in the retro play (t), Rex solus (w), Joke, Joke promotion, Type C
Genre: Retro
FEN: 2kr3K/1p1ppqrp/8/8/8/8/8/8
Input: James Malcom, 2020-05-11
Last update: Alfred Pfeiffer, 2020-10-14 more...
29 - P1379333
Guus Rol
Take back 1 white move and then #3
b) wTg5 nach d4
c) dann wKe1 nach c1, wTa1 nach d1
c) dann sBh6 nach a7
Henrik Juel: We await the detailed solution with bated breath, Andrew (2020-08-25)
James Malcom: For a), perhaps it’s something stupid -1. bxa6ep to prove that Black can’t castle. Either it’s a solution in one of the parts or it’s a false lead. (2020-08-26)
Mario Richter: Here's my guess:
a) R: 1. Td5xBg5, dann 1. a7!
b) R: b5xa6ep, dann 1. 0-0-0!
c) R: 1. Lg7xBf6, dann 1. Txd7!
d) R: 1. 0-0-0, dann 1. c6! (2020-08-26)
Mario Richter: still waiting for the official solution (2020-09-20)
James Malcom: As am I! (2020-09-20)
Keywords: Help retractor
Genre: 3#, Retro
FEN: 4k2r/2pb1p1r/Pp2pBpp/2P3RP/2p5/8/5PPP/R3K3
Input: A.Buchanan, 2020-08-25
Last update: A.Buchanan, 2020-08-25 more...
30 - P1379499
Andrew Buchanan
1135 Julias Fairies 02/10/2016
1. c4-c2! b3+ 2. c5-c3 bxc4ep+ 3. d6-d4 cxd5ep+ 4. e7-e5 dxe6ep+ 5. f8-f6 exf7ep#

By the double pawn move convention not:
1. ... b4? 2. ... bxc5 3. d4 cxd6 4. ... dxe7 5. ... exf8=D#

Not 1. c3? bxc3 2. d4 cxd4 3. e5 dxe5 4. f6 exf6 and no h#1 due to bPc5
play all play one stop play next play all
Either the current position is a starting position, or White has just played 0. ... b1-b2, from a position with an impossible check which must therefore have been the starting position itself. In either case, none of the Black pawns have ever moved, and so are eligible to make a double move. wPc1 has also never moved. But what of wPb2? We are up in the air as to whether b2-b4 is legal.

Since we can never prove that a position is not a starting position, the default convention is that it is *not* the starting position. Therefore, White has just begun the game with Black in check, and played 0. ... b1-b2, so is not able to play b2-b4 later.

Eventually, when Chess960 becomes played out, we will all be playing Chess4E71, so best to learn it now. There are three diagonals wPb2 may move along, but only one of them works. Rigorous retro reasoning allows all the pawns to make a double move *except* for wPb2. (Author)
Henrik Juel: No comment (2020-08-30)
James Malcom: I think that the simplest possbility to animate this, if Gerd has time that is, would be to allow a pawn to commence a double step fro anywhere. (2020-08-30)
A.Buchanan: Would also need non-standard e.p. (2020-08-31)
Mario Richter: Henrik walking in the footsteps of Epimenides: a comment saying "No comment" :-) (2020-09-20)
A.Buchanan: This is basically the simplest set of rules & conventions to allow chess with any starting arrangement of the orthodox pieces (2020-09-21)
Keywords: Chess4E71, En passant (4), Pac-Man
Genre: h#, Retro, Fairies
FEN: 5p1k/4p2p/3p4/2p5/2p5/8/1P6/B1P5
Input: A.Buchanan, 2020-08-30
Last update: A.Buchanan, 2020-10-27 more...
31 - P1380127
Nikola Predrag
(32) MatPlus.net Forum 15/8/2019
-1(s+w), dann #3?
R: 1. c4xb3ep b2-b4, dann 1. Sc3+ Kc2 2. Dd3+ Kxd3 3. 0-0-0#?!
But castling is illegal! This is because Black's dark squared bishop is a promoted piece and White's king must have moved to let the promotion through.
play all play one stop play next play all
Henrik Juel: Removing wPh2 might help (2020-09-21)
James Malcom: The illegality of the castling is intentional. (2020-09-21)
A.Buchanan: I guess it is intended as a joke. There are numerous cooks e.g. R: 1. Dh1xDh5 Td6-b6 dann 1. Sb2-d2+! (2020-09-22)
James Malcom: Andrew, the White king is in check from the Black bishop. Ep is the only legal way to resolve it. Your suggestion is illegal. Did you forget to eat breakfast again? :) (2020-09-23)
A.Buchanan: Ha this is just like when I play chess otb - so hard to spot extraordinarily distant black pieces on dark squares :-) (2020-09-23)
James Malcom: Sounds fair enough to me! And the position is legal, not illegal, Andrew. (2020-09-23)
A.Buchanan: I meant "no solution" - and I've classified it as a joke which I think is the composer's intent (2020-09-24)
James Malcom: Quite simply, I agree. (2020-09-24)
Mario Richter: I think the "normal usage" of the keyword "no solution" in the PDB so far is to indicate, that the intended solution fails e.g. because of some hidden defense (which corresponds to the german "unlösbar").
This problem doen't fall into that category! In fact, it has as solution, namely that there is no mate in 3 after the (forced) retractions!
(There are 1064 cooked problems with the keyword "no solution", only 9 "no solution" problems with the label "C+", and for all of the latter either the "no solution" or the "C+" is wrongly attributed.
Perhaps the simplest way to handle the Pedrag-problem is to add "intended" to the KW "no solution". (2020-09-25)
James Malcom: I agree, Mario. It is now doe. (2020-09-25)
A.Buchanan: Yes that's fair. Most jokes follow a template, but this is quite original. (2020-09-25)
more ...
Keywords: Belen Theme, Valladao Task, Help retractor, Castling as mating move, En passant in the retro play, Obtrusive material, Joke, no solution (Intentional), Cant Castler (wg)
Genre: Retro, 3#
FEN: 8/1pppp1p1/1R6/b6q/6N1/rp5Q/p5PP/RNk1K3
Input: James Malcom, 2020-09-21
Last update: Mario Richter, 2020-10-07 more...
32 - P1380195
Norbert Geissler
The Problemist Supplement 2018
after Andrew Buchanan
1. ... e3 2. Da5 Df3 3. b6 Dxa8#
play all play one stop play next play all
The task here is to maximize the number of necessary units in a homebase h#.
Henrik Juel: 1... e3 2.Da5 Df3 3.b6 Dxa8#
White (not Black) has no last move, so he has the move, and the stipulation is really h#2.5 (2020-09-23)
A.Buchanan: Can shift sBd7 to c7 for an entirely different mate, but alas one of sBg7h7 might be removed without losing soundness. (2020-09-24)
Keywords: Homebase (2), No legal last move for White
Genre: h#, Retro
FEN: r2qk1nr/pp1ppppp/8/8/8/8/1PPPPPP1/2BQKB2
Input: A.Buchanan, 2020-09-23
Last update: Alfred Pfeiffer, 2020-09-24 more...
33 - P1380264
Norbert Geissler
3 The Problemist Supplement 154, p. 646, 05/2018
Wie viele Lösungen?
1. Sh6 f4 2. 0-0 f5 3. Kh8 f6 4. Tg8 Txh6# Only one solution!
play all play one stop play next play all
The possible second solution 1. Th7 0-0 2. Td7 Ta1 3. De7 Txa8 4. Kd8 Txb8#
is illegal as white castling is not allowed (last move of white was made by King or Rook)
Henrik Juel: C+ Popeye 4.61 (2020-09-25)
Keywords: Homebase (2)
Genre: h#, Retro
FEN: rn1qk1nr/2p5/8/8/8/8/5P2/4K2R
Input: A.Buchanan, 2020-09-25
Last update: Alfred Pfeiffer, 2020-09-25 more...
34 - P1380439
James Malcom
MatPlus.net Forum 23/09/2020
(13+1) C+
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)
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...
35 - P1380440
James Malcom
Andrew Buchanan

MatPlus.net Forum 23/09/2020
JM, version AB
(10+1) C+
wK has moved 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

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

R: 1. Kc1xLc2 Lb1xTc2,Lb1xSc2 Easter Egg!
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)
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: James Malcom, 2020-10-08 more...
36 - P1380663
Pascal Wassong
1st prize
Partie Justificative en 9,5 coups
Cylindre vertical
1. d4 Sf6 2. Lh6 Tg8 3. e3 Tah8 4. Da6 Sxa6 5. Sd2 Tb8 6. 0-0-0 Tba8 7. Kb1 Sb8 8. La6 Tgh8 9. Sf1 Sg8 10. Le1
play all play one stop play next play all
Henrik Juel: C+ Jacobi 0.7.5
1.d4 Sf6 2.Bh6 Rg8 3.e3 Rah8 4.Qa6 Sxa6 5.Sd2 Rb8 6.O-O-O Rba8 7.Kb1 Sb8 8.Ba6 Rgh8 9.Sf1 Sg8 10.Be1
On a standard board Black would have made an even number of moves; not so here, with Ra8-h8-b8-a8 (2020-10-05)
Keywords: Unique Proof Game, Cylinder (vertical), Homebase (s), RIFACE Retro Composition Tourney (2016)
Genre: Retro, Fairies
FEN: rnbqkbnr/pppppppp/B7/8/3P4/4P3/PPP2PPP/1K1RBNNR
Input: A.Buchanan, 2020-10-05
Last update: A.Buchanan, 2020-10-06 more...
37 - P1380664
Michel Caillaud
2nd prize
(15+15) C+
Partie Justificative en 7,5 coups
Cylindre vertical
more ...
Keywords: Unique Proof Game, Cylinder (vertical), RIFACE Retro Composition Tourney (2016)
Genre: Retro, Fairies
Computer test: C+ Jacobi
FEN: r1bq1bnr/ppppp1pp/k3R3/6n1/7P/8/PPPP1PP1/RNBQKBN1
Input: A.Buchanan, 2020-10-05
Last update: A.Buchanan, 2020-10-06 more...
38 - P1380665
Michel Caillaud
Philippe Rouzaud

1st honourable mention
(14+15) cooked
Partie Justificative en 15,0 coups
Cylindre vertical
Henrik Juel: Jacobi 0.7.5 was too slow (for me) (2020-10-05)
Michel Caillaud: cooked (2020-10-05)
Keywords: Unique Proof Game, Cylinder (vertical), RIFACE Retro Composition Tourney (2016)
Genre: Retro, Fairies
FEN: 1nb2rk1/1pBppp2/1qpr2pn/7p/2PP1P2/5P1N/PP2B2K/1N2bQRR
Input: A.Buchanan, 2020-10-05
Last update: A.Buchanan, 2020-10-06 more...
39 - P1380666
Thierry Le Gleuher
Pascal Wassong
Jacques Dupin

2nd honourable mention
Partie Justificative en 8,0 coups
Cylindre vertical
Henrik Juel: C+ Jacobi 0.7.5
1.Sf3 b5 2.Sh4 Bf3 3.gxf3 b4 4.Bc6 dxc6 5.h3 Qd6 6.Rh2 Qxh2 7.Sg2 Qd6 8.O-O-O-O Qd8
Looks like kingside castling, but is loong castling with [Ra1] (2020-10-05)
Keywords: Unique Proof Game, Cylinder (vertical), RIFACE Retro Composition Tourney (2016)
Genre: Retro, Fairies
FEN: rn1qkbnr/p1p1pppp/2p5/8/1p6/5P1P/PPPPPPN1/1NBQ1RK1
Input: A.Buchanan, 2020-10-05
Last update: A.Buchanan, 2020-10-05 more...
40 - P1380667
Thierry Le Gleuher
3rd honourable mention
Partie Justificative en 9,0 coups
Cylindre vertical
Henrik Juel: C+ Jacobi 0.7.5
Cylinder-specific mate with triple-check (2020-10-05)
Keywords: Unique Proof Game, Cylinder (vertical), RIFACE Retro Composition Tourney (2016)
Genre: Retro, Fairies
FEN: rnbqkb2/pppp1p2/7N/7p/8/K3r3/PPPPP1PP/R1BQ1BNR
Input: A.Buchanan, 2020-10-05
Last update: A.Buchanan, 2020-10-05 more...
41 - P1380668
Michel Caillaud
1st commendation
Compléter la position pour
une Partie Justificative en 6,0
coups, se terminant par un
échecs quadruple (C+)
Cylindre vertical
1. e4 e6 2. Dxb7 Da3 3. Dxa7 Txa7 4. e5 Tb7 5. Ke2 Da8 6. Kf3 Tb3++++
play all play one stop play next play all
Henrik Juel: This proof game is C+ Jacobi 0.7.5 (2020-10-06)
A.Buchanan: Thanks Henrik: wish we could show any solution in the animation, by including a sequence of actual diagrams where a fairy move cannot be animated directly. All this requires to implement this is some documentation (2020-10-07)
Keywords: Unique Proof Game, Cylinder (vertical), RIFACE Retro Composition Tourney (2016)
Genre: Retro, Fairies
FEN: 8/8/4p3/8/8/8/8/8
Input: A.Buchanan, 2020-10-05
Last update: A.Buchanan, 2020-10-06 more...
42 - P1380669
Marco Bonavoglia
2nd commendation
(14+15) C+
Partie Justificative en 5,0 coups
2 solutions
Cylindre vertical
more ...
Keywords: Unique Proof Game, Cylinder (vertical), RIFACE Retro Composition Tourney (2016)
Genre: Retro, Fairies
Computer test: C+ Jacobi
FEN: rnbqk1n1/1pppppb1/p5pp/8/2P1P3/3P4/PP3PPP/RN2KBNR
Input: A.Buchanan, 2020-10-05
Last update: A.Buchanan, 2020-10-06 more...
43 - P1380676
Pascal Wassong
Axel Gilbert

3rd Place
Partie justificative en 12,5 coups
Anti Take & Make
Henrik Juel: Jacobi 0.7.5 was too slow for me (2020-10-05)
Keywords: Anti-Take & Make, Unique Proof Game, RIFACE Retro Composition Tourney (2015)
Genre: Retro, Fairies
FEN: rnbq1knr/p2P1P2/1P1ppp1P/8/7p/b1P1P1PR/2p1p1pP/1NBQKBNR
Input: A.Buchanan, 2020-10-05
Last update: A.Buchanan, 2020-10-07 more...
44 - P1380678
Pascal Wassong
Axel Gilbert

4th Place
Partie justificative en 8,0 coups
Anti Take & Make
Henrik Juel: C+ Jacobi 0.7.5
1.Sf3 Sc6 2.Se5 Sxe5 [+wSc6] 3.g3 Sd3+ 4.cxd3 [+bSc5] Se4 5.dxe4 [+bSd6] Sf5 6.exf5 [+bSh4] Sg6 7.fxg6 [+bSe5] Sxc6 [+wSb8] 8.Bg2 Sxb8 [+wSa6] (2020-10-05)
Keywords: Anti-Take & Make, Unique Proof Game, RIFACE Retro Composition Tourney (2015), Homebase (s)
Genre: Retro, Fairies
FEN: rnbqkbnr/pppppppp/N5P1/8/8/6P1/PP1PPPBP/RNBQK2R
Input: A.Buchanan, 2020-10-05
Last update: A.Buchanan, 2020-10-07 more...
45 - P1380679
Allan Bell
5th Place
Partie justificative en 13,5 coups
Anti Take & Make
Henrik Juel: Jacobi 0.7.5 was too slow for me (2020-10-05)
Keywords: Anti-Take & Make, RIFACE Retro Composition Tourney (2015), Unique Proof Game
Genre: Retro, Fairies
FEN: 1nb1k2r/1Qqpnpbp/1pP1P1P1/r6P/8/1pPp1p1p/PB1NPKPR/R4BN1
Input: A.Buchanan, 2020-10-05
Last update: A.Buchanan, 2020-10-07 more...
46 - P1380681
Marco Bonavoglia
6th Place
Partie justificative en 6,0 coups
Anti Take & Make
Henrik Juel: Solution
1.e4 f5 2.exf5 [+bPf4] g5 3.fxg6 e.p. [+bPg4] Sf6 4.g7 Bxg7 [+wPg8=B] 5.Bxh7 [+bPh5] Sxh7 [+wBd3] 6.Bde2 O-O
The Capture-free keyword is misleading: there are lots of captures, but the captured men 'make' a move to re-appear (2020-10-06)
A.Buchanan: Yes Henrik I started putting that on before I read the definition. I will pull those tags off soon. (2020-10-07)
more ...
Keywords: Anti-Take & Make, RIFACE Retro Composition Tourney (2015), Unique Proof Game, Home Circuit (wBe)
Genre: Retro, Fairies
Computer test: C+ Jacobi
FEN: rnbq1rk1/ppppp1bn/8/7p/5pp1/8/PPPPBPPP/RNBQKBNR
Input: A.Buchanan, 2020-10-05
Last update: A.Buchanan, 2020-10-07 more...
47 - P1380682
Oliver Sick
7th Place
Partie justificative en 8,0 coups
Anti Take & Make
Henrik Juel: C+ Jacobi 0.7.5
1.Sf3 f6 2.Se5 fxe5 [+wSc4] 3.Sb6 axb6 [+wSc4] 4.Sd6+ exd6 [+wSf7] 5.Sxd8 [+bQf6] Sc6 6.Sxc6 [+bSa5] bxc6 [+wSd4] 7.Sf3 Qxf3 [+wSg1] 8.exf3 [+bQf6] Qd8
Active Sg1 (2020-10-05)
Keywords: Anti-Take & Make, RIFACE Retro Composition Tourney (2015), Unique Proof Game
Genre: Retro, Fairies
FEN: r1bqkbnr/2pp2pp/1ppp4/n3p3/8/5P2/PPPP1PPP/RNBQKBNR
Input: A.Buchanan, 2020-10-05
Last update: A.Buchanan, 2020-10-07 more...
48 - P1380852
James Malcom
Andrew Buchanan

MatPlus.net Forum 12/10/2020
nach Josef Cumpe
Last two moves?
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)
Keywords: Last Moves?, Joke promotion (t), Rex solus, Type C, Castling in the retro play, Joke, Promotion in the retro play (t)
Genre: Retro
FEN: 2kr2K1/1p1p1npr/8/8/8/8/8/8
Input: A.Buchanan, 2020-10-12
Last update: Alfred Pfeiffer, 2020-10-14 more...
49 - P1380855
James Malcom
MatPlus.net Forum 12/10/2020
(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)
Keywords: under-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: James Malcom, 2020-10-14 more...
50 - P1380882
James Malcom
Andrew Buchanan

PDB Website 14/10/2020
nach Josef Cumpe
Last two moves?
See P1234039, P1375777 and P1380852.
The joke here is that pawns may promote to *any* unit (friend or enemy; officer, king or pawns).
Henrik Juel: R: 1... 0-0-0+ 2.a7-a8=sT
not 2.e7-e8=sK, because then sTa8 would have moved, and castling not allowed (2020-10-14)
A.Buchanan: Exactly, Henrik. Also: sB on 7th rank could retract to 8th rank, so we need sT instead (2020-10-14)
more ...
Keywords: Last Moves? (2), Type C, Castling in the retro play, Non-standard material (tt), Joke, Joke promotion (t), Promotion in the retro play (t)
Genre: Retro
FEN: 2kr3K/1r1r1qrR/7p/8/8/8/8/8
Input: A.Buchanan, 2020-10-14
Last update: Alfred Pfeiffer, 2020-10-14 more...
51 - P1380896
Andrew Buchanan
MatPlus.net Forum 12/10/2020
(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)
Keywords: Unique Proof Game, Joke, Joke promotion (sT), Homebase (w)
Genre: Retro
Computer test: C+ WinChloe
FEN: rnbqkbn1/1ppppp1r/8/8/8/8/P1PPPPP1/RNBQKB1R
Input: A.Buchanan, 2020-10-14
Last update: A.Buchanan, 2020-10-15 more...
52 - P1380992
Otto Gross
1 Aufbau (New York) 30/04/1943
(13+5) C+
1. gxf6ep! droht 2. Dg5#
1. ... gxh6 2. Sxh6#
1. ... Sf3+ 2. exf3#
1. ... Sxg2 2. e7#
1. ... Sxg6+ 2. Dxg6#
1. ... gxf6+ 2. Sxf6#
play all play one stop play next play all
'Aufbau': Das Problem des en-passant-Schlagens ist in unserer Aufgabe nicht die Schwierigkeit, der wir besonderen Wert beimessen, sondern es handelt sich lediglich darum, die Korrektheit der Stellung nachzuweisen, nämlich warum zuletzt nur f7-f5 von Schwarz geschehen sein kann.
f6-f5 oder Sh4-f3 kann nicht geschehen sein, sonst hätte der weisse König im Schach gestanden; die Möglichkeit, dass evtl. ein dritter Springer, in welchen der fehlende weisse Bauer umgewandelt wurde, bei der Placierung des schwarzen Königs auf g3 durch ein Abzugsschach (Sf2-g4 Kg3xg4) ermöglicht haben könnte, fällt fort, da der fehlende Bauer nur ein weisser Läufer geworden sein kann, der jetzt auf c8 steht. Der bei Beginn des Spiels vorhanden gewesene weisse Läufer muss auf seinem Platz geschlagen worden sein, da Be2 und g2 seine Entwicklung verhinderten.
SCHRECKE: Umwandlungsläufer wLc8! (2020-10-16)
Henrik Juel: C+ Popeye 4.61, after analysis proving that last move was f7-f5 (2020-10-16)
Keywords: En passant as key, Obtrusive material
Genre: 2#, Retro
Computer test: Popeye 4.61
FEN: 2B3N1/2P3p1/4P1PQ/4KpPp/5Pkn/8/3NP1P1/4B3
Input: Mario Richter, 2020-10-16
Last update: Alfred Pfeiffer, 2020-10-17 more...
53 - P1381229
Harry Goldsteen
18160 Die Schwalbe 302 04/2020
Alexander Kisljak zum Gedenken
'Schwalbe' 305 (10/2020) S.711: "Die Widmung erfolgt zur Erinnerung an Kisljaks 10. Todestag (27.12.1938-5.5.2010) sowie wegen der Darstellung des Kisljak-Themas (g/h-Linien); auch hat Kisljak selbst mit dem Grundschema dieser Aufgabe gelegentlich gearbeitet, siehe z.B. 'The Problemist' 1984, 1. Preis, P0002468)
Mario Richter: Perhaps some problem friends who do not know this little pearl will try to solve it themselves, so I'll add the soluton a little bit later. (2020-10-22)

Genre: Retro
FEN: qrbb4/1Brppp2/1Kp2p2/1Rp5/k2P4/R1P1P3/PPp3P1/Q7
Input: Mario Richter, 2020-10-22
Last update: Mario Richter, 2020-10-22 more...
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The problems of this query have been registered by the following contributors:

Gerd Wilts (14)
Markus Manhart (1)
Henri Nouguier (2)
Erich Bartel (2)
Frank Müller (1)
A.Buchanan (25)
James Malcom (4)
Mario Richter (4)