Die Schwalbe

10 problem(s) found in 2255 milliseconds (displaying 10 problem(s)). [COMMENTDATE>=20220810 AND G='h#' AND NOT S='Uralski Problemist' AND S='Phenix'] [download as LaTeX]

1 - P0009121
Tomislav Petrovic
2949 Phénix 69 12/1998
P0009121
(10+9) C+
h#2 (AP)
1. fxe3ep d8=S 2. Kxd5 0-0-0# (Td1#?)
play all play one stop play next play all
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)
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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...
2 - P0541844
Jerome Auclair
475 Phénix 7 08/1989
P0541844
(3+2) C+
h#2
3.1...
1) 1. Ke5 Kd3 2. Ld6 Tf5#
2) 1. Ke3 Tf2 2. Lf4 Te2#
3) 1. Lf4 Tf6 2. Ke5 Te6#
play all play one stop play next play all
Yuri Bilokin: anticipated P1097369 (2023-03-21)
comment

Genre: h#
Computer test: (Popeye C-Version 3.52 (2048 KB))
FEN: 8/2b2R2/8/8/2KNk3/8/8/8
Input: Michal Dragoun, 1998-04-09
Last update: hpr, 2010-06-04 more...
3 - P1100532
Jean-Marc Loustau
Phénix 2002
Spezialpreis
P1100532
(3+3) C+
h#3
2.1...
1) 1. Sb6 Tc8+ 2. Ka7 Tb8 3. Sa8 Tb7#
2) 1. Sa7 Ld7 2. Ka8 Lc8 3. Sb8 Lb7#
play all play one stop play next play all
Yuri Bilokin: the idea is not new P1005163 (2022-08-06)
Jean Marc Loustau: ***
The matrix and the mates are indeed the same; but in this problem (P1100532) there is one more significant feature which is, in fact the main idea (which is not on the P1005163):
The 2 white thematic pieces can already play on the mate square in the diagram position: thus we have a kind of "peri-white Grimwhaw" (a 3 moves manoeuvre to reach the mate square which was already reachable).
Of course I did no know the P1005163 when I have composed this one... I would say "fortunately", because if I had knew it, probably I would not have worked on this matrix: my final result, in my opinion, is interesting enough with its new feature to deserve the publication. (2022-08-14)
Yuri Bilokin: you can see 1...Bd5 2.Sa7 Rc6 3.Ka8 Rc8#
1...Be4 2.Sa7 Rc6 3.Ka8 Rc8#
1...Bf3 2.Sa7 Rc6 3.Ka8 Rc8#
1...Bg2 2.Sa7 Rc6 3.Ka8 Rc8# (2024-03-18)
comment

Genre: h#
Computer test: Popeye Windows-32Bit v4.51 (100000 KB)
FEN: 1kn5/2R5/n1B5/8/8/3K4/8/8
Input: hpr, 2010-02-13
Last update: hpr, 2010-02-13 more...
4 - P1187770
Mirko Degenkolbe
Phénix 2007
P1187770
(3+1) C+
h#6
1. Kh6 Lg7+ 2. Kg5 Se7 3. Kf4 Kb3 4. Ke3 Sd5+ 5. Kd2 Sc3 6. Kc1 Lh6#
play all play one stop play next play all
Yuri Bilokin: version given by me SuperProblem (Website) 30/10/2017 wKa3-a2 8/7k/5BN1/8/8/8/K7/8 (2022-12-12)
comment

Genre: h#
Computer test: Popeye Windows-32Bit v4.51 (100000 KB)
FEN: 8/7k/5BN1/8/8/K7/8/8
Input: hpr, 2011-02-18
Last update: Felber, Volker, 2020-11-16 more...
5 - P1187847
Vitaly Medintsev
5545 Phénix 168, p. 7425, 2008
P1187847
(4+3)
h#2
b) sLg7->g8
a) 1. Kxe6 e8=T 2. Ke6-f7 Se5#
b) 1. Kxg6 e8=S 2. Kg6-f7 Txf6#
play all play one stop play next play all
SCHRECKE: a)+b): C+, popeye 4.87 (2023-09-12)
comment
Keywords: Miniature, Phoenix, Zilahi
Genre: h#
FEN: 3K4/4P1b1/4RnN1/5k2/8/8/8/8
Input: Vitaly Medintsev, 2011-02-21
Last update: Alfred Pfeiffer, 2014-08-18 more...
6 - P1211811
Eric Huber
5936 Phénix 04/2009
P1211811
(1+3) C+
h#4
Beamtenschach
Bicolores
b) sLf1->e2
c) sLf1->d7
a) 1. Te6 Tf4 2. Ld3 Tf5+ 3. Kg6 Tf3+ 4. Le4 Te3#
b) 1. Tf6 Tg4+ 2. Kh5 Tg6 3. Tf5 Tg2+ 4. Lf3 Tf2#
c) 1. Tc8 Tc5+ 2. Kg4 Tc6 3. Tg8 Tc8+ 4. Tg7 Tc7#
play all play one stop play next play all
more ...
comment
Keywords: Functionary Chess, Aristocrat, Miniature
Genre: Fairies, h#
Computer test: Popeye 4.61
FEN: 8/8/2r5/6k1/2R5/8/8/5b2
Input: Hans Gruber, 2011-10-09
Last update: Arnold Beine, 2022-12-12 more...
7 - P1399641
Wilfried Neef
9202 Phénix 325 12/2021
Lob
Abt. h#n
PR Evgeni Fomichev
P1399641
(2+8) C+
h#5
1. Df5-f2 Th6xf6 2. Sd4-f3 Kd7xe6 3. Kf1-g2 Ke6-f5 4. Kg2-h3 Kf5-f4 5. Kh3-h4 Tf6-h6#
play all play one stop play next play all
Wilfried Neef: 1.Da5 Txf6+ 2.Sb5??
1.Db1 Txf6+ 2.Sc2?? (2024-01-06)
comment
Keywords: Minimal (T), Model mate, Switchback (T), Indian
Genre: h#
Computer test: Gustav 4.1c
FEN: 8/1ppK4/2n1pp1R/5q2/3n4/8/8/5k2
Input: Marcin Banaszek, 2022-03-05
Last update: Gunter Jordan, 2023-11-01 more...
8 - P1408618
Udo Degener
Mirko Degenkolbe

9376 Phénix 335 10/2022
P1408618
(9+7) C+
h#5
0.1.1...
Nullstellung
a) +wSe3
b) +wLc1
c) +wTa1
a) 1. ... Sf5 2. h5 e3 3. h4 Sxh4 4. Kg8 Sxg6 5. Th7 Lc4#
b) 1. ... e3 2. Th5 Lc4 3. Tf5 exf5 4. e4 fxg6 5. Lxb2 Lxb2#
c) 1. ... 0-0-0 2. Txf1 d4 3. Tf7 dxe5 4. Lf6 exf6 5. Th7 Td8#
play all play one stop play next play all
(MD1862)
more ...
comment
Keywords: Model mate, Castling (wl in c), Line opening (in a), Selfblock (in a+c), Model mate, Unpinning, Corner mate (in b+c), Line opening
Genre: h#
Computer test: Popeye WINDOWS98-32Bit-Version 3.77 (8192KB)
FEN: 7k/6b1/6pp/4p3/4P3/6p1/PPPPP1P1/4KB1r
Input: Felber, Volker, 2023-03-31
Last update: Gunter Jordan, 2023-04-02 more...
9 - P1408845
Andrew Buchanan
Phénix 11/2021
after J-F. Baudoin & J-C. Gandy
P1408845
(9+13)
-1s -1w -1s, dann h#1
R: 1. ... h2-h1=S+ 2. a7-a8=L Kc8-d8 dann 1. h1=T a8=D#
play all play one stop play next play all
AB: Mario was kind enough to check this 2-Jul-2021. I hope it's ok if I quote his email:

The trick with the light-squared black Bishop is fine, but makes things too complicated for rawbats. It will happily retract e.g. R: 1. ... h2-h1=S+ 2. Lb7-a8 Ke7xDd8, dann 1. Kd6 Df6# without noticing that the retractions lead to a conflict on the g-file: either wPh2 captured the original Bishop c8 on the g-file, then bPg7 was not available a a capture object for the remaining white pawn captures, or wPh2 captured the original bPg7 on the g-file, then the original light-squared black bishop c8 was not available a capture object for the remaining white pawn captures f2xe3xd4 (both on dark squares).
So brain-checking your retractor and your logical argumentation I found no defects, and I think the problem is sound now
corrects P0003922
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comment
Keywords: Help retractor, Allumwandlung
Genre: Retro, h#
FEN: B2k4/2pp4/8/8/1PPP4/1rpP2PN/1pppPK2/nrbq3n
Input: A.Buchanan, 2023-04-13
Last update: A.Buchanan, 2024-01-21 more...
10 - P1409841
Andrew Buchanan
1 Phénix 331, p. 12922, 06/2022
after A.Lubusov
P1409841
(15+6) C+
h#2* (AP)
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#
play all play one stop play next play all
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.
Corrects P0000615.
more ...
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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...
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The problems of this query have been registered by the following contributors:

Gerd Wilts (1)
Michal Dragoun (1)
hpr (2)
Vitaly Medintsev (1)
Hans Gruber (1)
Marcin Banaszek (1)
Felber, Volker (1)
A.Buchanan (2)