Mike Neumeier: The solution appears to be 1.fxe4 e.p. 2.e2 3.exf1=L 4.Ld3 5.Le4 6.Ld5 dxc3#. Was that the intention? (2013-02-18)
Arno Tüngler: There would even be a solution in 5 moves by 3.exf1=S 5.Sd5 Sb5#
However, in order to justify the e.p.-key there must be an AP prove that e2-e4 (and not a move by the wK or wRa1) was played as White's last move. Thus the only solution giving this in 6 moves is 1.fxe3 e.p. 2.e2 3.exf1=S 4.Sxd2 5.Sxb1 6.Sxa3 0-0-0!# (2013-02-18)
Mike Neumeier: It struck me as odd there was no solution listed. (2013-02-18)
Mike Neumeier: And, if we let black be the idle side, there is 1.Txg1 2.Lxh1 3.Kd1 4.Kc1 hxg1T#. What does the asterisk(*) mean? (2013-02-18)
Henrik Juel: The asterisk means that there is also a white mate if he had the move, in this case two mates, so maybe the stipulation should be ser-h#6**:
1.dxc3,Sb5# (2013-02-18)
Ladislav Packa: It is clear that e.p. is possible only when the wK and wRa1 done neither move.
What convention is used here for the right to castling? (2013-02-18)
Henrik Juel: White may castle, unless you can show that he has lost the right to castle. In this problem there is a major difficulty, I think: the position seems illegal.
White pawns captured b2xc3xd4xe5xf6, g2xf3, and axb, promoting on b8; Black captured bxc, dxc, and g3xh2. We cannot explain the destiny of [Ph7].
Reversing wPh3 and bPh2 seems to handle the illegality, but then the problem can be solved in 5 moves (2013-02-18)
Mike Neumeier: Thanks, Henrik. Maybe the stipulation was a typo. Considering all comments together, perhaps the stip should have been ser-h#5**, with the one solution being the 5-mover Arno gave. I do not think it can be proven, except by a stipulation of ser-h#5 that en passant is possible. Which leads to the question of convention. Can the existence of a unique solution as implied only by the stipulation be used to determine that en passant is permissible? Whether there is castling or not here seems immaterial. It is just another 6-move solution. There are 19 6-movers (Popeye) with one queenside castling among them. But only the one 5-mover. (2013-02-18)
Henrik Juel: By convention, an en passant capture as first move is not permitted, unless the pawn double step can be shown by some kind of retro analysis.
(Conversely, a castling is permitted, unless it can be shown by retro analysis that the right to castle has been lost, i.e., that king and/or rook has moved) (2013-02-18)
A.Buchanan: Suggested repair: Remove bPa4. Add AP to stipulation.
As Henrik points out, the diagram as it stands is illegal. We can't swap wPh3 & bPh2, because that allows 2 h#1 cooks.
Suppose we remove bPa4 instead. Then we still at least 5 White pawn captures: bxcxdxexf6 & gxf3. But wPh3 did still move from h2, so there are 3 Black pawn captures bxc, dxc & gxh2. So [bhP] died without capturing or promoting. [waP] must have promoted - so either [baP] was captured to clear the way, or [waP] captured to promote, and later [baP] promoted. Either way, all the numbers add up, and the position is legal. wPe4 cannot have just come from d3. So AP is triggered. Forward logic works just as before without bPa4. There is 1 5-move try, and 18 6-move tries, but AP eliminates them all because of need for castling to retrospectively justify the ep. (2013-02-23)
A.Buchanan: Mike asked: "Can the existence of a unique solution as implied only by the stipulation be used to determine that en passant is permissible?"
Answer: No. The stipulation does imply a default player to move, but otherwise cannot be used as a premise to determine game state (castling, en passant). (2022-03-21)
A.Buchanan: WinChloe & Yacpdb have the same cooked diagram as PDB, so I think this cook was in the design. I would like to post a sound version with bPa4 removed, and I think it would just be “Zigman correction” with no one else’s name mentioned in the credits. Is everyone ok with this? (2022-05-30)
Mario Richter: 'Bilten 1970' (printed 1971) contains on pp. 62-81 a complete report on the "Problem Duel Slovenia - Macedonia 1969", the problem here can be found on page 79 and is printed there exactly as given here.
Andrew's handling of the suggested correction (remove black pawn a4) is o.k. for me. (2022-05-31)
A.Buchanan: One question was not raised all those years ago. How does the "series mover" condition affect AP? How does flipping the player change our knowledge of the game history? If it's *consequent* series mover, then the flip erases all history: we use retro analysis to derive any information of the history of the game. But for regular series movers, the history is in some sense retained. Here, White's castling rights in the diagram position are the same as those after 6 single moves by Black. Is this correct? (2022-03-20, hidden) more ...
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A.Buchanan: What's the idea? If it's a length record, can't we shift all the pieces up and put wK on a1 to increase the solution length by one. (2022-03-15)
SCHRECKE: Andrew, it's look like an "A" for "Annemarie". (2022-03-15)
Henrik Juel: This is not the best-looking A, I have seen, so it should not be Keyword'ed Letter problem
Incidentally, the problem can also be tested by Popeye, in a flash (2022-03-15)
A.Buchanan: Thanks all! Letter A must be the concept, although I must admit I didn't see it. It's certainly closer to A than any other letter (excepting the Cyrillic alphabet) to it would be churlish to refuse it the keyword. I hope that, in the unlikely event that Hans ever dedicated a letter problem to me, he would use a less wispy font :) (2022-03-16)
Anton Baumann: C+ Alybadix (2022-03-14, hidden) more ...
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SCHRECKE: C+, popeye 4.85 (2021-02-19)
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t/Erhaltungen, t/Rex solus
Max Witte: Ich sehe keinen letzten schwarzen Zug. Versetzte man den Tf7 nach h7, sähe ich einen. (2021-07-08)
Max Witte: Aber dann ist 1.Lg7 kein kein Patt. (2021-07-08)
A.Buchanan: Maybe position legality is not considered a concern for this task (2021-07-08)
Mario Richter: Usually, there a separate record lists for legal positions and illegal ones.
So I think legality plays a role ... (2021-07-09)
HBae: Stellung mit wTh7 siehe P1103734 (2021-07-09)
HBae: Das dürfte inkorrekt sein, mit C- zu kennzeichnen. Der Rekord ist gleichzeitig materialbezogen vgl. P1103735 mit 7 Steinen. Rekord für illegale Stellung mit 4 Steinen siehe P1237827 (2021-07-09)
HBae: Allerdings ist die Stellung aus der PAS erspielbar nur dass Schwarz am Zuge ist. Vermutlich hat EB gesehen, dass Weiss nicht am Zuge sein kann. (2021-07-09)
HBae: Vgl. auch P1108944 P1182404 (2021-07-09)
HBae: Schwarz hat keinen letzten Zug, die Stellung ist illegal. (2010-12-17, hidden) more ...
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Mario Richter: Illegale Stellung - nicht-erklärbares Schach durch sTh8. (2010-09-25)
Anton Baumann: mögliche Korrektur: sDf6 nach f8, wBd6 nach e5, ser-s#12
1.b8=L 4.e8=S 7.Sxh8 8.Sg6 9.h8=L 11.La7 12.Df3+ Dxf3#
Diese Version ist C+, Gustav 4.1d (2021-08-21)
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Henrik Juel: The position is illegal, as black pawns have captured nine times, but only seven white men are missing.
What is the intended solution? (2015-04-07)
Mario Richter: I do not know the intended solution, but the following line of play does the job:
1. Qa2xb1 2. Qb1-a2 3. Qa2xa3 4. Qa3-c5 5. Ra4-b4 6. Ra5-a2 7. Ka6-a5 8. Ka5-a4 9. Ka4-a3 10. Rb4-a4 11. Ra4-a6 12. Ka3-a4 13. Ka4-a5 14. Ra2-a4 15. Ra4-b4 16. Ka5-a4 17. Ka4-a3 18. Ka3-a2 19. Ka2-b1 20. Ra6-a2 21. Pa7-a5 22. Pa5-a4 23. Pa4-a3 24. Rb4-a4 25. Ra4-a8 26. Ra8-d8 27. Rd8xd2 28. Kb1xc1 29. Kc1-d1 30. Kd1-e2 31. Ke2-f3 32. Kf3-g4 33. Kg4-h5 34. Kh5-h6 35. Qc5-h5 Pg7-g8=N# (2015-04-08)
Henrik Juel: Thanks, Mario, for the nice solution, which certainly looks intended (2015-04-08)
Anton Baumann: C+ Alybadix (2020-12-01)
A.Buchanan: Suppose remove wBf6 and wLb1, and shift wSe4 to e6, with sDa2 to b1. Does that work as ser-h#34? (2020-12-02)
Anton Baumann: wSe4 nach e6?? 1.Tb4 Sc7#
Wenn 2 w Steine reduzieren, dann diejenigen welche ohnehin geschlagen werden:
zB: -wLb1, -wBa3, sTa4 nach b4, sDa2 nach a4 (7+12) serh#34: 1.Da3 2.Tba4 3.Dc5 4.Tb4 ... (2020-12-03)
A.Buchanan: Haha Anton I should have spotted that. Also wSe4 stops sDb1-f5-c5, which makes me think about sDb1 sTa2a3 sKa4 (and the two white units removed, of course). Is that ser-h#38? (2020-12-03)
Anton Baumann: Auch so ser-h#34: 1.Ka5 3.Tb4 5.Ka3 7.Ta6 9.Ka5 10.Ta4 13.Dc5 14.Tb4 18.Kb1 ... (2020-12-04)
A.Buchanan: If that could work, a follow-up idea would be to replace sDb1 with sBg2 and go back to ser-h#35 with key 1. g1=D! (1. g1=L?) 2. Dc5 3. Dxa3 4. Dc5 etc as before. But I don’t have a powerful engine for such problems (2020-12-02, hidden) more ...
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Henrik Juel: The condition Lame means that the position is illegal and must be made legal by adding, moving, or removing one man, before the stipulated play starts (2017-09-24)
Alfred Pfeiffer: NL nach wBc1->h7: 1. Ld5,..,La8 h8=D,T# (2017-09-25)
A.Buchanan: Is it bPg2? (2024-01-17)
A.Buchanan: I don't know how it is in Swedish, but in English, Lame is a slur. And the acronym doesn't work. I would suggest "Alarm" instead, standing for "Alarm! Legalize by Adding, Removing or Moving". But with only two examples, it's not worth a keyword yet. (2024-01-17)
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A.Buchanan: If one allows promotion to sB (and there seems no reason to disallow it since promotion to pawn, king and foreign units are allowed) then the problem is cooked. There is no universally agreed notion of how a pawn can move if it starts on the first rank. Does it get a double hop, and if so on which rank? But the problem is unsound in any case. (2022-02-10)
James Malcom: That is if, yes. But I don't think this problem ought to be left as is: a demonstration of the levels of absurdity and tomfoolery old rules used to allow. Promotion to a piece of another color and dummies were loopholes, yes, but promotion to a black pawn was never included, not even implicitly. All pawns are pieces, but not all pieces are pawns. (2022-02-10)
A.Buchanan: Can't White play 3. a8=DTLSB - basically any White unit? (2022-02-09, hidden)
James Malcom: No, as bNa8 is needed to guard c7. (2022-02-09, hidden) more ...
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Henrik Juel: maybe 1.e8=K (2021-04-30)
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James Malcom: While this is indeed a very early predecessor to P1267725, I seriously doubt that it can be called an "anticipation." (2021-05-02)
A.Buchanan: I agree James. "Anticipation" is a wounding thing, and the word is not to be bandied about indescriminately :-) Surely there is room for many numerous compositions with the brave chain of wPs reaching across the board, echoing the chain of composers building on one another's ideas over the centuries...
The pawn chain takes 9 captures to establish. No more captures are needed for wPb to promote to alfil on b8. f8 is the alternative promotion square. As you know, I think this kind of foolish promotion counting is fun, so therefore am happy to stick with ALh2. It would count as non-standard material, even though the normal complement of such Alfils is 0. Note that ALg3 would be illegal! There are 8 orbits for Alfils, and only 6 are achievable, even with promotion. (2021-05-02)
A.Buchanan: What kind of promotion was available in Persian/Arabic chess at the time is unclear to me. Although Western chess limited promotion to just a nebbish Ferz (see https://en.wikipedia.org/wiki/Rules_of_chess#History), Indian Shaturanga had other ideas: the default promotion rule I encountered when looking at this was to the type of piece that began on that column (bearing in mind that the black Ferz began on e8). Thus if Persian/Arabic chess borrowed from the Indian form we could have promoted on f8 to Alfil, at the cost of only 2 more captures. (2021-05-02)
A.Buchanan: The duals are pretty unsavoury, not just the transposition at the start. Many of them involve mating on the back rank. Exploration with Olive is amusingly complicated by the fact that both Ferz and Alfil are by default both figured with left-leaning bishop. Don't know how to change that... However, I have found: 4k3/4P3/4P3/4P3/4P2B/4P1Q1/4P3/4K2R which is sound (B=Alfil, Q=Ferz in this diagram #6 C+ Popeye 4.85 (2021-05-02)
A.Buchanan: Could do it with 2 Alfil instead, but then it's 16 pawn captures if we insist on promoting in the Chaturanga way on f8. Do need one promoted Alfil for soundness. The good thing about these weedy pieces is that they help avoid cooks. The knight was terrible. Does anyone mind that wR is shifted to h1? Nice that such a "retro" problem has retro aspects in the chess sense too :D (2021-05-02)
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SCHRECKE: C+, popeye 4.87
1) 1. Ta5 LIa3 2. LIb8 Txa7#
2) 1. LIb8 Th7 2. Ta5 LIh8# (2023-07-27, hidden) more ...
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SCHRECKE: C+, popeye 4.87
1) 1. Kc4 2. Gb3 3. Kc3 4. Gb2 5. Kc2 6. Kb1 7. Ka1 8. Gb1 Ta8#
2) 1. Gc3 2. Ke3 3. Kf3 4. Gg3 5. Kg2 6. Kh1 7. Gg2 8. Gg1 Th8#
3) 1. Ke3 2. Kf3 3. Gf2 4. Kg3 5. Gg2 6. Kh2 7. Kh1 8. Gh2 Tb1# (2023-07-27, hidden) more ...
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