9 problem(s) found in 2161 milliseconds (displaying 9 problem(s)). [COMMENTDATE>=20220810 AND NOT A='Healey, Frank' AND A='Keym, Werner'] [download as LaTeX]
Keywords: Partial Retro Analysis (PRA), Castling
Genre: Retro, 3#
FEN: r3k2r/bRp1p1p1/1pn1P2B/rB2p3/n1P1Q3/2P1P3/1P4P1/R3K2R
Reprints: 172 Eigenartige Schachprobleme 2010
(8) Die Schwalbe 241 02/2010
A Die Schwalbe 283, p. 9, 02/2017
Input: Gerd Wilts, 2009-01-03
Last update: Mu-Tsun Tsai, 2023-07-19 more...
Genre: Retro, 3#
FEN: r3k2r/bRp1p1p1/1pn1P2B/rB2p3/n1P1Q3/2P1P3/1P4P1/R3K2R
Reprints: 172 Eigenartige Schachprobleme 2010
(8) Die Schwalbe 241 02/2010
A Die Schwalbe 283, p. 9, 02/2017
Input: Gerd Wilts, 2009-01-03
Last update: Mu-Tsun Tsai, 2023-07-19 more...
s) R: 1. b3xBa2 f6xBg7
w) R: 1. ... f6xBg7 2. b3xBa2
All captures are accounted for by hungry pawns, wBf1 died at home, & bPh waylaid. wPa & bPg can only have been captured on their home squares. bPc6 & bPd6 can't have just moved as they would close off bB homes. Most interestingly, wPd4 must have captured light-squared bB, but did not do so recently, as wPf3 would lock the south-east cage. Need Ng1 to shield wKh1, allowing bKg3. So the two last single moves are clear, and may have occurred in either order.
w) R: 1. ... f6xBg7 2. b3xBa2
All captures are accounted for by hungry pawns, wBf1 died at home, & bPh waylaid. wPa & bPg can only have been captured on their home squares. bPc6 & bPd6 can't have just moved as they would close off bB homes. Most interestingly, wPd4 must have captured light-squared bB, but did not do so recently, as wPf3 would lock the south-east cage. Need Ng1 to shield wKh1, allowing bKg3. So the two last single moves are clear, and may have occurred in either order.
Keywords: Last Move? (BxB,BxB), Type D (DD), Economy record (Last Move? Type DD), Volet Pawn (2), waylaid (sBh)
Genre: Retro
FEN: 8/ppp3P1/2pp4/8/4P3/7P/p1PPPkPK/4bq2
Input: Gerd Wilts, 2009-06-08
Last update: A.Buchanan, 2024-02-19 more...
Genre: Retro
FEN: 8/ppp3P1/2pp4/8/4P3/7P/p1PPPkPK/4bq2
Input: Gerd Wilts, 2009-06-08
Last update: A.Buchanan, 2024-02-19 more...
a) +sKd3 1. 0-0-0? Castling rights lost
b) +sKf7 1. g8=D#
+sKd3? und 1.0-0-0# macht nicht, veil die Stellung ist illegal (saB & sbB).
Das Brett wird um 180° gedreht, dann +sKf7 und 1. g7-g8=D#
b) +sKf7 1. g8=D#
+sKd3? und 1.0-0-0# macht nicht, veil die Stellung ist illegal (saB & sbB).
Das Brett wird um 180° gedreht, dann +sKf7 und 1. g7-g8=D#
Henrik Juel: I believe that the try is
add sK on d3 and 1.0-0-0#
This addition is illegal, however:
the white h-pawns captured all 15 missing black men, but [Pa7,b7] need three captures to promote, and only two white men are missing (2023-04-13)
comment
add sK on d3 and 1.0-0-0#
This addition is illegal, however:
the white h-pawns captured all 15 missing black men, but [Pa7,b7] need three captures to promote, and only two white men are missing (2023-04-13)
comment
Keywords: Joke, Board Rotation (180), Add pieces (sK), Cant Castler
Genre: Retro
FEN: 6B1/4R2P/P6P/B6P/7P/7P/1P5P/R3K1N1
Input: Gerd Wilts, 2010-06-23
Last update: A.Buchanan, 2023-04-15 more...
Genre: Retro
FEN: 6B1/4R2P/P6P/B6P/7P/7P/1P5P/R3K1N1
Input: Gerd Wilts, 2010-06-23
Last update: A.Buchanan, 2023-04-15 more...
1. Tc3! Kg1 2. Tc2 Kh1 3. 0-0-0#
1. ... Kh2 2. Kf1 Kh1 3. Th3#
1. ... Kh2 2. Kf1 Kh1 3. Th3#
Keywords: Miniature Collection (0051727), Castling as mating move, Aristocrat, Rex solus (s), Castling (wg)
Genre: 3#
FEN: 8/8/8/8/8/8/6k1/R1R1K3
Reprints: 20 Der Schachzug (FV Schach Berlin) 20 08/1977
Input: Felber, Volker, 2010-09-11
Last update: Mario Richter, 2022-08-11 more...
Genre: 3#
FEN: 8/8/8/8/8/8/6k1/R1R1K3
Reprints: 20 Der Schachzug (FV Schach Berlin) 20 08/1977
Input: Felber, Volker, 2010-09-11
Last update: Mario Richter, 2022-08-11 more...
1. Td1? 0-0!
1. 0-0-0 0-0 2. Tg1+ Kh8 3. Dg7#
1. 0-0-0 0-0 2. Tg1+ Kh8 3. Dg7#
Die letzten Züge waren g7-g5 g6xLh7. Daher 1.h5xg6 e.p.! 0-0-0 2.a8D#.
Das ist der erste (korrekte) Zweizüger mit den konsekutiven Spezialzügen En passant-Schlag, Rochade und Umwandlung (Valladao). (vgl. P1080516 (inkorrekt) und P1184197)
Das ist der erste (korrekte) Zweizüger mit den konsekutiven Spezialzügen En passant-Schlag, Rochade und Umwandlung (Valladao). (vgl. P1080516 (inkorrekt) und P1184197)
Keywords: Valladao Task
Genre: Retro
FEN: r3k3/P2p3P/pp1P1p1p/3p2pP/6nq/4bPrR/1P2PpRB/5BnK
Input: Gerd Wilts, 2011-01-06
Last update: Rainer Staudte, 2022-09-11 more...
Genre: Retro
FEN: r3k3/P2p3P/pp1P1p1p/3p2pP/6nq/4bPrR/1P2PpRB/5BnK
Input: Gerd Wilts, 2011-01-06
Last update: Rainer Staudte, 2022-09-11 more...
7 - P1406456
Werner Keym
OP016 The Hopper Magazine I02 25/06/2022
corrects Keym Schach-Echo 1967 / Die Schwalbe 2007
(15+5)
#1 AP
b) - Lh8
Werner Keym
OP016 The Hopper Magazine I02 25/06/2022
corrects Keym Schach-Echo 1967 / Die Schwalbe 2007
(15+5)
#1 AP
b) - Lh8
a) 1. ... bxa3ep 2. Dc3#!
(2. 0-0#?)
1. 0-0#? (rights lost)
b) 1. ... bxa3ep 2. 0-0#!
(2. Dc3#?)
1. 0-0#? (Black to move if rights remain)
a) White & Black have made 11+1 pawn captures, accounting for all missing material. bPa captured to b file (must be bPb2 now, to get behind wPb) so bPh promoted on h1, to supply balance. Therefore White cannot castle. Black has no last move, so by Article 15 we can conclude that Black has the move. The only way to give Black a move is R: 1. a2-a4 a3xNb2. Therefore ep is legal, and indeed that is Black's only move. After 0... bxa3ep, White mates with 1.Dc3#! not 1.0-0#? since castling is illegal. AP is not used in this twin, but is available as a condition in order to make twins as similar as possible, and show that the difference in behaviour comes just from wBh8, not from conditions.
b) Now there is a second white unit missing, which gives more retro possibilities. One case is that bPh might have captured to g-file, to promote (or to be captured if original bPg promoted), so White may retain castling rights, but in this case it must be Black to move. So 1.0-0#? doesn't work as a solution. Alternatively, if White has lost castling rights, Black might have just played c2xNb1=R, or c3xNb2 or a/c5xb4. So in this scenario we cannot prove unconditionally that it's really Black to play.
However, under adversarial AP, White makes a double claim: firstly that it is Black to move (AP Type Keym), and secondly that ep is legal (AP Type Petrovic). If White retains castling rights, then both of these items are correct, and the ep must be bxa3 not bxc3. So White mates with 1.0-0#! for AP justification, not 1.Dc3#?.
(2. 0-0#?)
1. 0-0#? (rights lost)
b) 1. ... bxa3ep 2. 0-0#!
(2. Dc3#?)
1. 0-0#? (Black to move if rights remain)
a) White & Black have made 11+1 pawn captures, accounting for all missing material. bPa captured to b file (must be bPb2 now, to get behind wPb) so bPh promoted on h1, to supply balance. Therefore White cannot castle. Black has no last move, so by Article 15 we can conclude that Black has the move. The only way to give Black a move is R: 1. a2-a4 a3xNb2. Therefore ep is legal, and indeed that is Black's only move. After 0... bxa3ep, White mates with 1.Dc3#! not 1.0-0#? since castling is illegal. AP is not used in this twin, but is available as a condition in order to make twins as similar as possible, and show that the difference in behaviour comes just from wBh8, not from conditions.
b) Now there is a second white unit missing, which gives more retro possibilities. One case is that bPh might have captured to g-file, to promote (or to be captured if original bPg promoted), so White may retain castling rights, but in this case it must be Black to move. So 1.0-0#? doesn't work as a solution. Alternatively, if White has lost castling rights, Black might have just played c2xNb1=R, or c3xNb2 or a/c5xb4. So in this scenario we cannot prove unconditionally that it's really Black to play.
However, under adversarial AP, White makes a double claim: firstly that it is Black to move (AP Type Keym), and secondly that ep is legal (AP Type Petrovic). If White retains castling rights, then both of these items are correct, and the ep must be bxa3 not bxc3. So White mates with 1.0-0#! for AP justification, not 1.Dc3#?.
corrects P1108454
Henrik Juel: here is my guess
a) 0... bxa3ep 1.Dc3#
b) 1.0-0# (2022-12-05)
A.Buchanan: Comments on the proposed solution welcome (2023-08-21)
more ...
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Henrik Juel: here is my guess
a) 0... bxa3ep 1.Dc3#
b) 1.0-0# (2022-12-05)
A.Buchanan: Comments on the proposed solution welcome (2023-08-21)
more ...
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Keywords: a posteriori (AP) (Type Keym), a posteriori (AP) (type Petrovic), No legal last move for Black, En passant as key, Castling, Cant Castler (wk)
Genre: Retro
FEN: 7B/2P5/3P4/1P2Q3/PpP1N3/1P1P4/1p1RBP2/brk1K2R
Input: A.Buchanan, 2022-12-05
Last update: A.Buchanan, 2023-08-22 more...
Genre: Retro
FEN: 7B/2P5/3P4/1P2Q3/PpP1N3/1P1P4/1p1RBP2/brk1K2R
Input: A.Buchanan, 2022-12-05
Last update: A.Buchanan, 2023-08-22 more...
8 - P1409983
Andrey Frolkin
Werner Keym
1.67 Eigenartige Schachprobleme , p. 196, 2010
(10+2)
Letzter Zug?
Andrey Frolkin
Werner Keym
1.67 Eigenartige Schachprobleme , p. 196, 2010
(10+2)
Letzter Zug?
R: 1. g3xBh4 h5-h4 and e.g. 2. Kf4-g5 Kh4-h3
Keywords: Economy record (Last Move? Type A), Last Move? (BxB), Non-standard material (L), Type A, Type B (a fortiori), Economy record (Last Move? Type B), Minimal
Genre: Retro
FEN: 8/1p5P/6PP/5BK1/6PP/5B1k/6NP/8
Input: A.Buchanan, 2023-05-28
Last update: A.Buchanan, 2023-05-31 more...
Genre: Retro
FEN: 8/1p5P/6PP/5BK1/6PP/5B1k/6NP/8
Input: A.Buchanan, 2023-05-28
Last update: A.Buchanan, 2023-05-31 more...
R: 1. Ke8xDf7#
Version of Die Schwalbe 1990, see P0000180
SCHRECKE: vergleiche: P0000180 (2023-07-25)
more ...
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SCHRECKE: vergleiche: P0000180 (2023-07-25)
more ...
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Keywords: Last Move? (KxD), Type C, Type M
Genre: Retro
FEN: nBk2Rn1/pp1ppKp1/1p3p1p/8/8/8/8/8
Input: Miguel Ambrona, 2023-07-25
Last update: A.Buchanan, 2023-07-27 more...
Genre: Retro
FEN: nBk2Rn1/pp1ppKp1/1p3p1p/8/8/8/8/8
Input: Miguel Ambrona, 2023-07-25
Last update: A.Buchanan, 2023-07-27 more...
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The problems of this query have been registered by the following contributors:
Gerd Wilts (4)Felber, Volker (2)
A.Buchanan (2)
Miguel Ambrona (1)
A.Buchanan: I don't think it's as straightforward as this. Under PRA, there are 2 parts: a) wK & sD rights ok b) wD & sK ok. We tackle each separately. a) 1. 0-0? 0-0-0! 1. Td1! b) 1. 0-0-0? 0-0! 1. Tf1! The forward play is messy, and there are three promoted units, but the amazing paradox is that White wins by not castling. This is not a case of mutual exclusion. This is why it got first prize, I think. (2023-07-18)
Mu-Tsun Tsai: Yeah, on second thought I indeed got it the wrong way; it is in fact possible that Kq castling are both valid (I have the proof game in fact), and I take your word that the other side is also true. (2023-07-19)
A.Buchanan: For complete retro proof, need both retro logic & non-unique proof games. For the latter, maybe can show the legality of rn2k1nr/ppp1p1pp/4P2B/4p3/2P1Q3/2P5/PP2P1PP/R1b1KB1R. From here, can branch to the two ways of getting the two rook promotions: (a1+h8 vs h1+h8) (2023-07-19)
Henrik Juel: If Andrew's analysis holds, the keys are correct by Popeye 4.61
But there are duals in each part (2023-07-20)
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