11 problem(s) found in 2765 milliseconds (displaying 11 problem(s)). [COMMENTDATE>=20200919 AND NOT K='Hilfsrückzüger' AND S='Phenix' AND K='En passant'] [download as LaTeX]
1. dxc3ep 2. Kxb5 3. Kxc6 4. Kd7 5. Ke8 6. 0-0 Th8#
Aber es geht auch R: 1. Kb2-a1!?
Aber es geht auch R: 1. Kb2-a1!?
Keywords: En passant, Castling (sk), Seriesmover, Consequent, Non-standard material (sLb1), Valladao Task, Promotion in the retro play (sLb1), Obvious promotion ((sLb1)), Superseded by (P1012052)
Genre: Retro, Fairies
FEN: 7r/5pnR/2P3pR/pPpn3p/1kPp4/3P4/P2pP3/Kbb5
Input: Gerd Wilts, 1995-06-03
Last update: A.Buchanan, 2022-09-14 more...
Genre: Retro, Fairies
FEN: 7r/5pnR/2P3pR/pPpn3p/1kPp4/3P4/P2pP3/Kbb5
Input: Gerd Wilts, 1995-06-03
Last update: A.Buchanan, 2022-09-14 more...
2 - P0002758
Andrej N. Kornilow
1078 Phénix 15-16 12/1991
(25+0)
Färbe die Steine! Welches waren die letzten 9 Einzelzüge?
Andrej N. Kornilow
1078 Phénix 15-16 12/1991
(25+0)
Färbe die Steine! Welches waren die letzten 9 Einzelzüge?
James Malcom: Solution? (2020-11-07)
Mario Richter: I do not know the official solution, but the following works:
wBb7 wBf7 wBb6 wBg6 wBc5 wTf5 wLf4 wBg4 wBe3 wKg3 wTh3 wDf2 wBh2 wSf1 wSh1
sLg8 sDh8 sBa7 sBc7 sBh7 sBe6 sBf6 sKh6 sBe5 sLg1
wCaps: h5xg6ep f3xTg4 g4xTh5 e6xSf7 d5xSe6 a4xBb5
sCaps: d7xLe6
R: 1. h5xg6ep g7-g5 2. Tg5-f5 d7xLe6 3. f3xTg4 Th4-g4 4. g4xTh5 Kg6-h6 5. Tf5-g5 (2020-11-10)
comment
Mario Richter: I do not know the official solution, but the following works:
wBb7 wBf7 wBb6 wBg6 wBc5 wTf5 wLf4 wBg4 wBe3 wKg3 wTh3 wDf2 wBh2 wSf1 wSh1
sLg8 sDh8 sBa7 sBc7 sBh7 sBe6 sBf6 sKh6 sBe5 sLg1
wCaps: h5xg6ep f3xTg4 g4xTh5 e6xSf7 d5xSe6 a4xBb5
sCaps: d7xLe6
R: 1. h5xg6ep g7-g5 2. Tg5-f5 d7xLe6 3. f3xTg4 Th4-g4 4. g4xTh5 Kg6-h6 5. Tf5-g5 (2020-11-10)
comment
Keywords: Colouring problem, Last Moves? (9), En passant
Genre: Retro
FEN: 6BQ/PPP2P1P/1P2PPPK/2P1PR2/5BP1/4P1KR/5Q1P/5NBN
Reprints: (34) Die Schwalbe 144 12/1993
Input: Gerd Wilts, 1995-06-03
Genre: Retro
FEN: 6BQ/PPP2P1P/1P2PPPK/2P1PR2/5BP1/4P1KR/5Q1P/5NBN
Reprints: (34) Die Schwalbe 144 12/1993
Input: Gerd Wilts, 1995-06-03
1. fxe3ep d8=S 2. Kxd5 0-0-0# (Td1#?)
White has made 6 pawn captures with one missing black piece unaccounted for, that by parity can only have been captured by an officer. White's last move cannot have been a pawn capture. If R: 1.f2-f3, then sLg1 was promoted, implying 7 captures by black pawns - one too many. So if White can prove they retain castling rights, then the ep is on. Hence AP Petrovic is valid.
White has made 6 pawn captures with one missing black piece unaccounted for, that by parity can only have been captured by an officer. White's last move cannot have been a pawn capture. If R: 1.f2-f3, then sLg1 was promoted, implying 7 captures by black pawns - one too many. So if White can prove they retain castling rights, then the ep is on. Hence AP Petrovic is valid.
Henrik Juel: 0... fxe3ep 1.d8S Kxd5 2.0-0-0#. Not -1.f2? and Lg1 is caught. (2004-09-16)
Vaclav Kotesovec: Similar problems should not be labeled as "C+". Such a designation is only acceptable if the entire analysis was performed by a computer program. (2023-08-03)
Henrik Juel: In principle I agree, Vaclav
But PDB does not (yet) allow HC+, so I find it acceptable to use the C+ label, when you also tell the whole story after 'Computer test:' below (2023-08-03)
A.Buchanan: Hopefully Gerd will have more time at some point, and can expand the functionality in this and other areas. In the meantime, engine solving of conventional retros including AP, is in its infancy. Retractor 2 has some effectiveness, but is still basic. And there is nothing that yet grasps the intricacies of castling/ep etc. However AP problems do often contain considerable forward chess, and the C+ tag is very useful to filter out those that have already been solved forwardly, without pretending that these are in any sense fully solved (2023-08-04)
Ladislav Packa: I know the definition of AP, but I don't understand the logic behind it. The move 1.fxe3 e.p. proves that White CAN castling. But the solution (2. ...Rd1#?) claims that castling is MANDATORY. From my point of view, AP is correct when only castling is necessary for the solution and the Rook move would be a dual. (2023-08-04)
A.Buchanan: @Ladislav: I am not sure how to help you. Maybe you can read this page from Retro Corner: https://www.janko.at/Retros/Glossary/APosteriori.htm (2023-08-05)
Ladislav Packa: Andrew, what should the article help me with? I quote the final sentence:
Some people still oppose this rule and argue that it should certainly not be the default convention. (2023-08-05)
Henrik Juel: You could view it this way, Ladislav
h#2 means that it is Black to move, so White made last move
What was last move? A little analysis shows just three possibilities: f2-f4, move by Ta1, or move by Ke1
So normally we cannot assume that last move was f2-f4
But if White can castle, then the last move was f2-f4
So if we could start with 0... 0-0-0, then 1.fxe3ep would be legitimate
AP says that you are allowed to reverse the sequence of events; first do the ep capture, then later legitimize it by castling
Was this helpful? (2023-08-05)
Ladislav Packa: Henrik, you don't have to explain that to me. I've done a few AP issues myself, like P1348357. But that doesn't mean I agree with AP's logic. I already wrote it - the term "you can castle" is applied as "you must castle". But these are only problems where, in addition to castling, the Rook move can also be used, I consider that a dual.
From that point of view, the P1000662 issue is perfectly fine for me. (2023-08-05)
Joost de Heer: AP: By castling, you prove a posteriori that the ep-capture was not just a try but the actual solution. Without castling, the ep-solution just is that: a try.
So: Try 1. fe3 ep e8=S 2. Kd5 Rd1 - but ep capture not allowed, as there is no proof that f2-f4 must've been the last move.
Solution 1. fe3 ep e8=S 2. Kd5 OOO - Now the ep capture was justified because white castled, thereby proving that the last move before the diagram position indeed was f2-f4. (2023-08-06)
Joost de Heer: See e.g. P1052919 : The try is an ep capture which is unjustified. (2023-08-06)
A.Buchanan: OK Ladislav: I think I get your point. If one solution with castling justifies the e.p., then based on that certainty, why shouldn't an alternative solution with no castling *then* be allowed as well? There are problems in which one twin shows 0-0-0 and the other shows 0-0. Each is based on the other in a similar way, so the idea of dependency is not new. Why are we not allowed to add other "parasitic" solutions as well? Why can we only have the "paying" solutions? We can't say that we are restricted to one solution: that's not the way chess problems operate! And this is just in the help world - in the adversarial world it might get even more complicated. Is this your issue, Ladislav? (2023-08-07)
Ladislav Packa: I don't want to unnecessarily prolong this discussion. However, I will add one more note: in this position, white castling is also possible without e.p. in Black's 1st move. If B1 were an indifferent move, then white can 1...0-0-0! The Codex of Chess Composition writes about it in Article 16 (1):
Castling convention. Casting is permitted unless it can be proven that it is not permissible.
In our case, 0-0-0 is possible because White's last move exists - e2-e4! It does not matter if it is this move or some a2-a3, both moves are equivalent. EP does not prove the possibility of casting, it would be legal even without it. (2023-08-07)
A.Buchanan: Ladislav was what I wrote your issue pls? Y/N :-) (2023-08-07)
Ladislav Packa: I have no problem, I'm just expressing my own opinion about the AP convention. (2023-08-07)
A.Buchanan: OK cos I think the point I raised is a real one that should be addressed by theory some day. Clearly from the nice problem that you composed Ladislav you understand the mechanics very well. From a justification perspective it's all a bit iffy, but that's why it's controversial. Under RS it's really the only way one can end up actually eping, and it's proved compositionally fertile. So that's enough to justify (2023-08-08)
Ladislav Packa: No need to apologize. This is a normal discussion with different views on the issue. Maybe it will come to some conclusion.
I just want to point out the fact that it is not the e.p. that authorizes castling, because according to the Codex castling is possible regardless of the e.p. It's the exact opposite: castling authorizes the possibility of e.p. (2023-08-08)
Joost de Heer: "I just want to point out the fact that it is not the e.p. that authorizes castling, because according to the Codex castling is possible regardless of the e.p. It's the exact opposite: castling authorizes the possibility of e.p."
You misinterpret AP. The e.p. capture does not authorize castling, castling provides a justification later on (hence the 'a posteriori') for the legality of ep.
Usually, for ep justification you need to examine all game trees that lead to the diagram, and only if all game trees end with the double-step, then ep is allowed.
With AP, you examine all the game trees including the actual play. If all those game trees have as last move before the diagram position the double step, then ep is possible.
In this case, if white doesn't castle, then there are game trees which don't have as last move the double step, and therefore AP logic dictates that the ep capture was illegal. However, all game trees which lead to the diagram and which have castling in the actual play have as last move before the diagram position the double step, hence AP dictates that the ep capture is legal. (2023-08-09)
Ladislav Packa: Joost: A simple question - is white allowed to castle after any 1st move by black (except e.p.)? (2023-08-09)
Joost de Heer: Of course he is. AP only is used to combine the ep justification with castling, not the castling right per se. (2023-08-09)
more ...
comment
Vaclav Kotesovec: Similar problems should not be labeled as "C+". Such a designation is only acceptable if the entire analysis was performed by a computer program. (2023-08-03)
Henrik Juel: In principle I agree, Vaclav
But PDB does not (yet) allow HC+, so I find it acceptable to use the C+ label, when you also tell the whole story after 'Computer test:' below (2023-08-03)
A.Buchanan: Hopefully Gerd will have more time at some point, and can expand the functionality in this and other areas. In the meantime, engine solving of conventional retros including AP, is in its infancy. Retractor 2 has some effectiveness, but is still basic. And there is nothing that yet grasps the intricacies of castling/ep etc. However AP problems do often contain considerable forward chess, and the C+ tag is very useful to filter out those that have already been solved forwardly, without pretending that these are in any sense fully solved (2023-08-04)
Ladislav Packa: I know the definition of AP, but I don't understand the logic behind it. The move 1.fxe3 e.p. proves that White CAN castling. But the solution (2. ...Rd1#?) claims that castling is MANDATORY. From my point of view, AP is correct when only castling is necessary for the solution and the Rook move would be a dual. (2023-08-04)
A.Buchanan: @Ladislav: I am not sure how to help you. Maybe you can read this page from Retro Corner: https://www.janko.at/Retros/Glossary/APosteriori.htm (2023-08-05)
Ladislav Packa: Andrew, what should the article help me with? I quote the final sentence:
Some people still oppose this rule and argue that it should certainly not be the default convention. (2023-08-05)
Henrik Juel: You could view it this way, Ladislav
h#2 means that it is Black to move, so White made last move
What was last move? A little analysis shows just three possibilities: f2-f4, move by Ta1, or move by Ke1
So normally we cannot assume that last move was f2-f4
But if White can castle, then the last move was f2-f4
So if we could start with 0... 0-0-0, then 1.fxe3ep would be legitimate
AP says that you are allowed to reverse the sequence of events; first do the ep capture, then later legitimize it by castling
Was this helpful? (2023-08-05)
Ladislav Packa: Henrik, you don't have to explain that to me. I've done a few AP issues myself, like P1348357. But that doesn't mean I agree with AP's logic. I already wrote it - the term "you can castle" is applied as "you must castle". But these are only problems where, in addition to castling, the Rook move can also be used, I consider that a dual.
From that point of view, the P1000662 issue is perfectly fine for me. (2023-08-05)
Joost de Heer: AP: By castling, you prove a posteriori that the ep-capture was not just a try but the actual solution. Without castling, the ep-solution just is that: a try.
So: Try 1. fe3 ep e8=S 2. Kd5 Rd1 - but ep capture not allowed, as there is no proof that f2-f4 must've been the last move.
Solution 1. fe3 ep e8=S 2. Kd5 OOO - Now the ep capture was justified because white castled, thereby proving that the last move before the diagram position indeed was f2-f4. (2023-08-06)
Joost de Heer: See e.g. P1052919 : The try is an ep capture which is unjustified. (2023-08-06)
A.Buchanan: OK Ladislav: I think I get your point. If one solution with castling justifies the e.p., then based on that certainty, why shouldn't an alternative solution with no castling *then* be allowed as well? There are problems in which one twin shows 0-0-0 and the other shows 0-0. Each is based on the other in a similar way, so the idea of dependency is not new. Why are we not allowed to add other "parasitic" solutions as well? Why can we only have the "paying" solutions? We can't say that we are restricted to one solution: that's not the way chess problems operate! And this is just in the help world - in the adversarial world it might get even more complicated. Is this your issue, Ladislav? (2023-08-07)
Ladislav Packa: I don't want to unnecessarily prolong this discussion. However, I will add one more note: in this position, white castling is also possible without e.p. in Black's 1st move. If B1 were an indifferent move, then white can 1...0-0-0! The Codex of Chess Composition writes about it in Article 16 (1):
Castling convention. Casting is permitted unless it can be proven that it is not permissible.
In our case, 0-0-0 is possible because White's last move exists - e2-e4! It does not matter if it is this move or some a2-a3, both moves are equivalent. EP does not prove the possibility of casting, it would be legal even without it. (2023-08-07)
A.Buchanan: Ladislav was what I wrote your issue pls? Y/N :-) (2023-08-07)
Ladislav Packa: I have no problem, I'm just expressing my own opinion about the AP convention. (2023-08-07)
A.Buchanan: OK cos I think the point I raised is a real one that should be addressed by theory some day. Clearly from the nice problem that you composed Ladislav you understand the mechanics very well. From a justification perspective it's all a bit iffy, but that's why it's controversial. Under RS it's really the only way one can end up actually eping, and it's proved compositionally fertile. So that's enough to justify (2023-08-08)
Ladislav Packa: No need to apologize. This is a normal discussion with different views on the issue. Maybe it will come to some conclusion.
I just want to point out the fact that it is not the e.p. that authorizes castling, because according to the Codex castling is possible regardless of the e.p. It's the exact opposite: castling authorizes the possibility of e.p. (2023-08-08)
Joost de Heer: "I just want to point out the fact that it is not the e.p. that authorizes castling, because according to the Codex castling is possible regardless of the e.p. It's the exact opposite: castling authorizes the possibility of e.p."
You misinterpret AP. The e.p. capture does not authorize castling, castling provides a justification later on (hence the 'a posteriori') for the legality of ep.
Usually, for ep justification you need to examine all game trees that lead to the diagram, and only if all game trees end with the double-step, then ep is allowed.
With AP, you examine all the game trees including the actual play. If all those game trees have as last move before the diagram position the double step, then ep is possible.
In this case, if white doesn't castle, then there are game trees which don't have as last move the double step, and therefore AP logic dictates that the ep capture was illegal. However, all game trees which lead to the diagram and which have castling in the actual play have as last move before the diagram position the double step, hence AP dictates that the ep capture is legal. (2023-08-09)
Ladislav Packa: Joost: A simple question - is white allowed to castle after any 1st move by black (except e.p.)? (2023-08-09)
Joost de Heer: Of course he is. AP only is used to combine the ep justification with castling, not the castling right per se. (2023-08-09)
more ...
comment
Keywords: a posteriori (AP) (Type Petrovic), En passant as key, Castling (wg), Promotion (S), Valladao Task
Genre: Retro, h#
Computer test: HC+ Popeye v4.87 + simple retro-logic
FEN: 8/3P2p1/2PP4/1ppPp3/2pkPp2/5PP1/6Pp/R3K1b1
Input: Gerd Wilts, 1999-02-27
Last update: A.Buchanan, 2023-09-11 more...
Genre: Retro, h#
Computer test: HC+ Popeye v4.87 + simple retro-logic
FEN: 8/3P2p1/2PP4/1ppPp3/2pkPp2/5PP1/6Pp/R3K1b1
Input: Gerd Wilts, 1999-02-27
Last update: A.Buchanan, 2023-09-11 more...
s) 1. Tc6+ Dxc6+ 2. d5 exd6ep#
w) 1. Dc6+ d5 2. exd6ep+ Txc6#
w) 1. Dc6+ d5 2. exd6ep+ Txc6#
Keywords: En passant
Genre: h#
Computer test: (Popeye WINDOWS98-32Bit-Version 3.75 (2048 KB))
FEN: 8/3prp1B/K2QPB2/4Pq2/1pr1k3/3pp1P1/8/8
Input: hpr, 2003-01-09
Last update: A.Buchanan, 2013-08-13 more...
Genre: h#
Computer test: (Popeye WINDOWS98-32Bit-Version 3.75 (2048 KB))
FEN: 8/3prp1B/K2QPB2/4Pq2/1pr1k3/3pp1P1/8/8
Input: hpr, 2003-01-09
Last update: A.Buchanan, 2013-08-13 more...
1. h1=D 2. Dxf3 3. Dxg4 4. f3 5. f2 6. f1=T 7. Txf5 8. Tc5 9. f5 10. f4 11. f3 12. f2 13. f1=L 14. Lb5 15. Kc4 16. Dd4 17. g4 18. g3 19. g2 20. g1=D 21. Dxg6 22. Dgd3 23. g5 24. g4 25. g3 26. g2 27. g1=S 28. Se2 29. Sc1 30. Sa2 31. axb3ep 32. Sb4 33. Sd5 cxb3#
Henrik Juel: In the position after 30.Sa2, the last white move must have been b2-b4, allowing the ep capture. This is permitted by the stipulation's c (= consequential), requiring that all intermediate positions are legal.
The content is all-promotion plus one D-promotion.
The retro content is very small, but traditionally consequential series movers are considered to be retro problems (2014-09-07)
paul: 1.h1=B 2.Bxf3 3.Bc6 4.Kc4 5.f3 6.f2 7.f1=R 8.Rxf5 9.Rc5 10.Bb5 11.f5 12.fxg4 13.g3 14.g2 15.g1=S 16.Se2 17.Sc1 18.g4 19.g3 20.g2 21.Sa2 22.g1=Q 23.Qxg6 24.Qd3 25.g5 26.g4 27.g3 28.g2 29.g1=Q 30.Qgd4 etc. (2022-07-12)
A.Buchanan: If I've got it right, consequential sm is more than just asking that intermediate positions are legal. It involves at every move potentially a complete recalculation of rights. In regular sm and Alsatian fairy conditions, rights carry over from one move to the next. In Alsatian fairy conditions, all positions must be legal. Is this correct? (2022-07-12)
Henrik Juel: Yes, I think you are right, Andrew (2022-07-12)
comment
The content is all-promotion plus one D-promotion.
The retro content is very small, but traditionally consequential series movers are considered to be retro problems (2014-09-07)
paul: 1.h1=B 2.Bxf3 3.Bc6 4.Kc4 5.f3 6.f2 7.f1=R 8.Rxf5 9.Rc5 10.Bb5 11.f5 12.fxg4 13.g3 14.g2 15.g1=S 16.Se2 17.Sc1 18.g4 19.g3 20.g2 21.Sa2 22.g1=Q 23.Qxg6 24.Qd3 25.g5 26.g4 27.g3 28.g2 29.g1=Q 30.Qgd4 etc. (2022-07-12)
A.Buchanan: If I've got it right, consequential sm is more than just asking that intermediate positions are legal. It involves at every move potentially a complete recalculation of rights. In regular sm and Alsatian fairy conditions, rights carry over from one move to the next. In Alsatian fairy conditions, all positions must be legal. Is this correct? (2022-07-12)
Henrik Juel: Yes, I think you are right, Andrew (2022-07-12)
comment
Keywords: Seriesmover, Consequent, Kindergarten Problem, Allumwandlung (dtlds), En passant, Excelsior, Promotion (dtlsd x5)
Genre: Retro, Fairies
FEN: 8/6p1/5pP1/5Pp1/pP1k1pP1/K1p2P2/2P4p/8
Input: Frank Müller, 2014-09-05
Last update: A.Buchanan, 2022-07-12 more...
Genre: Retro, Fairies
FEN: 8/6p1/5pP1/5Pp1/pP1k1pP1/K1p2P2/2P4p/8
Input: Frank Müller, 2014-09-05
Last update: A.Buchanan, 2022-07-12 more...
6 - P1288722
Arnold Beine
Best Problems 2005
3. Preis
L. Vitale Memorial
(3+11)
h#19
Doppellängstzüger
Arnold Beine
Best Problems 2005
3. Preis
L. Vitale Memorial
(3+11)
h#19
Doppellängstzüger
1. a5 d4 2. c5 dxc6ep 3. Db6 cxb7 4. Dh6 bxc8=S 5. Dc1+ Ka2 6. Dh6 Sd6+ 7. Dxd6 Kb1 8. Dh2 Ka1 9. Db8 d5 10. Dh2 d6 11. Da2+ Kxa2 12. 0-0-0 dxe7 13. d5 Kb3 14. Td6 Ka4 15. Th6 Kb5 16. Ta6 Kxa6 17. g5 Kb5 18. Lh6 Kc6 19. Lf8 exf8=D,T (UW-Dual)
Keywords: Valladao Task, En passant, Castling, Maximummer (Doppel-)
Genre: Fairies
FEN: r1bqkb2/ppppp1p1/8/3P4/8/8/3P4/K7
Reprints: A4387 Phénix (178), p. 7731, 11/2008
Input: Erich Bartel, 2014-09-30
Last update: Alfred Pfeiffer, 2014-09-30 more...
Genre: Fairies
FEN: r1bqkb2/ppppp1p1/8/3P4/8/8/3P4/K7
Reprints: A4387 Phénix (178), p. 7731, 11/2008
Input: Erich Bartel, 2014-09-30
Last update: Alfred Pfeiffer, 2014-09-30 more...
1. Tb1+! Sxb1 2. Da3+ Sxa3 3. 0-0+ Sb1 4. a8=T+ La7 5. d5+ e5 6. dxe6ep+ Tg7+ 7. Kh1 e2 8. Te1 h5 9. b8=D h4 10. Db7 h3 11. Dg2 hxg2#
1. d3-d4+! f7-f5 2. g5xf6ep+ Tg4-g6 3. 0-0+ Lf4-c1 4. Kg1-h1 h5-h4 5. Lg3-h2 h4-h3 6. f6-f7 b5-b4 7. f7-f8=L h6-h5 8. Lf8-d6 h5-h4 9. Lh2-g1 h3-h2 10. Ld6xh2 h4-h3 11. Tf2-g2 h3xg2#
Keywords: Checking key, En passant, Castling, under-promotion (L), Valladao Task, Pawn mate
Genre: s#
FEN: 8/5p1B/7p/1p4Pp/5br1/1N1P2B1/5R2/1k2K2R
Input: Marcin Banaszek, 2020-11-09
Last update: Alfred Pfeiffer, 2020-11-09 more...
Genre: s#
FEN: 8/5p1B/7p/1p4Pp/5br1/1N1P2B1/5R2/1k2K2R
Input: Marcin Banaszek, 2020-11-09
Last update: Alfred Pfeiffer, 2020-11-09 more...
1. a4 d5 2. Ta3 Lg4 3. Te3 Lf3 4. exf3 Kd7 5. Lb5 Kd6 6. Se2 d4 7. 0-0 d3 8. Kh1 dxe2 9. d4 exf1=L 10. d5 Ld3 11. Te2 Lf5 12. Dd3 Lc8 13. Lf4+ e5 14. dxe6ep+
Keywords: Unique Proof Game, Valladao Task, Castling, En passant, under-promotion (l), Pronkin Theme (l)
Genre: Retro
Computer test: C+ Euclide 1.01, no solution in 12.5
FEN: rnbq1bnr/ppp2ppp/3kP3/1B6/P4B2/3Q1P2/1PP1RPPP/1N5K
Reprints: Problemesis 4 08/1998
M4 Phénix 66, p. 4112, 09/1998
13 Orbit 30, p. 318, 04/2006
Input: A.Buchanan, 2021-07-03
Last update: Alfred Pfeiffer, 2021-11-26 more...
Genre: Retro
Computer test: C+ Euclide 1.01, no solution in 12.5
FEN: rnbq1bnr/ppp2ppp/3kP3/1B6/P4B2/3Q1P2/1PP1RPPP/1N5K
Reprints: Problemesis 4 08/1998
M4 Phénix 66, p. 4112, 09/1998
13 Orbit 30, p. 318, 04/2006
Input: A.Buchanan, 2021-07-03
Last update: Alfred Pfeiffer, 2021-11-26 more...
10 - P1391300
Igor Vereshchagin
Michel Caillaud
IV Phénix 206, p. 8574, 06/2011
(15+12) C+
BP in 15.5
Igor Vereshchagin
Michel Caillaud
IV Phénix 206, p. 8574, 06/2011
(15+12) C+
BP in 15.5
1. e2-e4 c7-c5 2. Lf1-d3 c5-c4 3. Sg1-e2 c4-c3 4. 0-0 c3xd2 5. c2-c4 e7-e6 6. Se2-c3 Lf8-a3 7. Dd1-e2 d2-d1=S 8. f2-f4 Sd1-f2 9. b2xa3 Sf2-h3 10. g2xh3 Ke8-e7 11. Tf1-f2 Ke7-f6 12. Kg1-f1 Kf6-g6 13. e4-e5 f7-f5 14. e5xf6ep Kg6-h6 15. f4-f5 g7-g5 16. f5xg6ep#
Keywords: Unique Proof Game, Valladao Task, Castling, En passant (2), under-promotion (s), Ceriani-Frolkin Theme (s)
Genre: Retro
Computer test: Euclide 1.01, no solution in 14.5
FEN: rnbq2nr/pp1p3p/4pPPk/8/2P5/P1NB3P/P3QR1P/RNB2K2
Reprints: 791 Problemskak 17, p. 9, 2012
Input: A.Buchanan, 2021-07-03
Last update: Alfred Pfeiffer, 2021-11-26 more...
Genre: Retro
Computer test: Euclide 1.01, no solution in 14.5
FEN: rnbq2nr/pp1p3p/4pPPk/8/2P5/P1NB3P/P3QR1P/RNB2K2
Reprints: 791 Problemskak 17, p. 9, 2012
Input: A.Buchanan, 2021-07-03
Last update: Alfred Pfeiffer, 2021-11-26 more...
1. ... e6 2. 0-0? Lxh7# (castling rights lost)
1. ... Txh7 2. Tf8 Te7#
1. cxb3ep Txh7 2. Tf8? Te7# (ep needs AP justification)
1. cxb3ep e6 2. 0-0! Lxh7#
White pawns have captured 9 times right-to-left, accounting for all but one missing Black unit. So by parity, there were no other pawn captures by White. So wBb never left that file, and Black cannot have just played Bb3xa2 behind it. sBa was waylaid on a-file by an officer.
So if Black moved last, it must have been Ke8 or Th8, and Black has lost castling rights.
On the other hand, if White moved last, then Black needs a tempo move. The only possible one is ep capture. (1. Tg8+? is check.) But the ep capture is only legal if Black retains castling rights, so Black's second move must indeed be 0-0 for A Posteriori justification.
In this case, last moves were R: 1. b2-b4 b3xDa2 & e.g. 2. Le3-d4,~ b4-b3 3. d4xSc5,~ Sa6-c5,~ with many ways for White to release Black.
1. ... Txh7 2. Tf8 Te7#
1. cxb3ep Txh7 2. Tf8? Te7# (ep needs AP justification)
1. cxb3ep e6 2. 0-0! Lxh7#
White pawns have captured 9 times right-to-left, accounting for all but one missing Black unit. So by parity, there were no other pawn captures by White. So wBb never left that file, and Black cannot have just played Bb3xa2 behind it. sBa was waylaid on a-file by an officer.
So if Black moved last, it must have been Ke8 or Th8, and Black has lost castling rights.
On the other hand, if White moved last, then Black needs a tempo move. The only possible one is ep capture. (1. Tg8+? is check.) But the ep capture is only legal if Black retains castling rights, so Black's second move must indeed be 0-0 for A Posteriori justification.
In this case, last moves were R: 1. b2-b4 b3xDa2 & e.g. 2. Le3-d4,~ b4-b3 3. d4xSc5,~ Sa6-c5,~ with many ways for White to release Black.
Keywords: a posteriori (AP), RIFACE Retro Solving Tourney (2022), En passant as key, Castling (sk), Tempo Move, waylaid (sBa)
Genre: h#, Retro
Computer test: HC+ Popeye v4.87 & simple retro thinking
FEN: 4k2r/1N1p3p/3P4/1PPPP3/1PpBBP2/P1N3K1/p7/R6R
Input: A.Buchanan, 2023-05-20
Last update: A.Buchanan, 2023-09-11 more...
Genre: h#, Retro
Computer test: HC+ Popeye v4.87 & simple retro thinking
FEN: 4k2r/1N1p3p/3P4/1PPPP3/1PpBBP2/P1N3K1/p7/R6R
Input: A.Buchanan, 2023-05-20
Last update: A.Buchanan, 2023-09-11 more...
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https://pdb.dieschwalbe.de/search.jsp?expression=COMMENTDATE%3E%3D20200919+AND+NOT+K%3D%27Hilfsr%C3%BCckz%C3%BCger%27+AND+S%3D%27Phenix%27+AND+K%3D%27En+passant%27
The problems of this query have been registered by the following contributors:
Gerd Wilts (3)hpr (1)
Frank Müller (1)
Erich Bartel (1)
Marcin Banaszek (2)
A.Buchanan (3)
GW: Yes, that's the solution, and the problem seems indeed to be cooked. I don't know if it has been corrected. (2003-04-28)
James Malcom: I believe that the intent was that the sLc1 must be the orginal one, and thus an impediment to wK foreplay, as the wBc6 "must" have captured the e7 Black pawn on its way from f2. The problem is that it can take the alternative path fxsLf3xDe3xTc5-c6, and there are enough White pieces to capture for the Black b pawn to make it d2 and for the d pawn to make it to c2. (2021-09-14)
James Malcom: It turns out this problem actually was corrected a long time later: P1012052 (2021-09-14)
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