Die Schwalbe

13 problem(s) found in 3062 milliseconds (displaying 13 problem(s)). [COMMENTDATE>=20200919 AND NOT K='Hilfsrückzüger' AND A='Buchanan, Andrew']

1 - 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...
2 - 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...
3 - P1375440
Andrew Buchanan
17465v Die Schwalbe 291, p. 492, 06/2018
Rewan Demontay gewidmet
(3+4) C+
White Dummy f2
1. c1=DU Lxe7 2. d3 Kf1 3. d2 Ke2 4. d1=L Kd2 5. Lb3 Kxc1 6. La2 Lf6#
play all play one stop play next play all
Added 1 Dummy to P1359493, and changed the dedicatee. My luck with this little series continues to hold: the dedicatee's surname begins with a D!
James Malcom: Andrew, I just found this today-I thank you very much, but perhaps it holds no more, for my true name is known now! (2020-10-28)
Keywords: Miniature, Promotion in the key (du), Schnoebelen Theme (du), Prentos Theme (du), Ceriani-Frolkin Theme (du), Promotion (du,l), Bartel-Thema (du)
Pieces: i = Dummy (DU)
Genre: h#, Fairies
Computer test: Popeye 4.81
FEN: 8/4p3/5B2/8/3p4/8/2p2I2/k5K1
Input: A.Buchanan, 2020-05-03
Last update: A.Buchanan, 2020-10-29 more...
4 - 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...
5 - 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...
6 - 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...
7 - 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...
8 - 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...
9 - P1381285
Andrew Buchanan
James Malcom

MatPlus.net Forum 25/10/2020
(5+7) C+
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)
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...
10 - P1381369
Andrew Buchanan
MatPlus.net Forum 28/10/2020
SPG in 4.0
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)
Keywords: Unique Proof Game, Tempo Move, Task (Construction) (4), Superseded by (P1381879), x pieces capture on one square (4)
Genre: Retro
FEN: rn1qkbnr/2pppppp/b7/8/8/4P3/PPPP1PPP/RNB1K1NR
Input: A.Buchanan, 2020-10-29
Last update: James Malcom, 2020-11-14 more...
11 - P1381879
Andrew Buchanan
MatPlus.net Forum 3/11/2020
(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)
Keywords: Unique Proof Game, Task (Construction) (6), x pieces capture on one square (6)
Genre: Retro
Computer test: Natch 3.1
FEN: r3kbnr/1bpppppp/q7/8/4P3/8/P1PP1PPP/RNB1K1NR
Input: A.Buchanan, 2020-11-14
Last update: Alfred Pfeiffer, 2020-11-16 more...
12 - P1382432
Andrew Buchanan
Facebook 26/11/2020
(11+15) C+
1. g4 h5 2. Lg2 hxg4 3. Lf3 gxf3 4. Kf1 fxe2+ 5. Kg2 exd1=T! 6. Kf3! Txc1 7. Ke2 Te1+ 8. Kxe1
play all play one stop play next play all
Henrik Juel: Excellent find, Andrew
Hint: length is 7.5 (2020-11-25)
A.Buchanan: Thanks Henrik - amazed to find it’s not in WinChloe or Yacpdb (2020-11-26)
A.Buchanan: The animation fails for "SPG", instead "KBP" is needed. (2020-11-26)
more ...
Keywords: Unique Proof Game, Homebase (2), Pure Round Trip (K5), Ceriani-Frolkin Theme (t), Prentos Theme (t), Tempo Loss
Genre: Retro
Computer test: C+ Natch 3.1 C+ Euclide 1.01 for 6.0, 6.5, 7.0 & 7.5 moves, which is conclusive.
FEN: rnbqkbnr/ppppppp1/8/8/8/8/PPPP1P1P/RN2K1NR
Reprints: chess.stackexchange.com 26/11/2020
Input: A.Buchanan, 2020-11-25
Last update: A.Buchanan, 2020-11-26 more...
13 - P1382488
Andrew Buchanan
Thomas Thannheiser

1509 Julias Fairies 25/05/2020
(13+15) C+
PG in 8.5
Alphabetic Chess
Aims to be the shortest SPG for a homebase position which demonstrates this fairy condition.
Henrik Juel: I cheated and used Jacobi
Nice condition-specific manouver by Sb1 (2020-11-26)
Keywords: Unique Proof Game, Homebase (2), Alphabetic Chess, Economy record (Alphabetic homebase)
Genre: Retro, Fairies
Computer test: Jacobi v0.4.7
FEN: rnbqkbnr/1ppppppp/8/8/8/8/2PPPPPP/1NBQKBNR
Input: A.Buchanan, 2020-11-26
Last update: A.Buchanan, 2020-11-26 more...
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The problems of this query have been registered by the following contributors:

A.Buchanan (12)
James Malcom (1)