Die Schwalbe

44 problem(s) found in 6298 milliseconds (displaying 44 problem(s)). [COMMENTDATE>=20220810 AND NOT S='The Westminster Papers' AND K='En passant als Schlüssel'] [download as LaTeX]

1 - P0000058
Leonid M. Borodatow
5758v Die Schwalbe 103 02/1987
P0000058
(13+9) C+
h#3
b) sBa6 statt sLa6
a) 1. ... exf6ep 2. 0-0-0 Lxf4 3. Td7 a8=D#
b) 1. ... Kxf4 2. Te7 e6 3. Tb8 axb8=D,T#
play all play one stop play next play all
Anton Baumann: Mattdual in b): 3.Tb8 axb8=D,T# (2022-12-16)
A.Buchanan: So Borodatow got it all working! In a) Black might have captured hxgxf and axPb. So castling rights might still be maintained with the ep. In b) on the other hand, it must be axb, bxa, exf and wPgxh6, so there was the cage. Promotion to TD is tolerated in the final move, although it may not be puristic, without the convention, too many mates would be excluded (2022-12-16)
comment
Keywords: En passant as key, Castling (sg), Cant Castler, Valladao Task
Genre: h#, Retro
Computer test: HC+ Popeye v4.87 & basic retro thinking
FEN: r3k3/P7/b3r1pP/4PpBP/3nnpKR/5PRB/5PP1/7N
Input: Gerd Wilts, 1995-06-03
Last update: A.Buchanan, 2022-12-16 more...
2 - P0000758
Gerd Rinder
1033 Die Schwalbe 21 06/1973
1. Preis
P0000758
(7+11)
Remis (AP)
Weiß ist patt. 1. cxb6ep ist nur zulässig, wenn Schwarz diese a posteriori durch die Rochade rechtfertigt. Weiß kann aber so spielen, daß Schwarz nicht rochieren kann, z.B. 1. ... Lxc7 2. bxc7
play all play one stop play next play all
Guus Rol: This is an incorrect interpretation of the AP-convention. Rules outrank goals in the definition of all GAMES. Therefore the legitimacy of a move cannot be restricted by the desire to achieve the goal (in this case: Remis). The proper way to view AP is that executing e.p. invalidates the legitimacy of all lines of future play that do not contain 0-0-0! In that sense black and white are forced to cooperate. In whatever freedom remains they can compete for the prize promised in the stipulation. By the way, this understanding of AP is not only more logical, it is also much more interesting as a playing field for AP-composition. (2005-09-21)
mri: citeWeiß kann aber so spielen, daß Schwarz nicht rochieren kann, z.B. 1. ... Lxc7 2. bxc7
/cite
How does white prevent black from castling after 1. cxb6 e.p. Ba7xb6+?
E.g. 2.Kxb6 a1=R 3.a7 Rxa7, or 2.Ka4 Bd8xc7 3.a7 Bb8. (2005-09-22)
VL: 1.c5xb6ep(??) a7xb6+ 2.Kxb6 a1R 3.Kb7 R1xa6 4.Rc8! (R6a7#?? illegal).
This study is correct under the generally accepted understanding of AP
a la' N.Petrovic'. Antiform (looking possibly somewhat strange):
Black's unsuccessful try. (2005-10-03)
Guus Rol: Generally accepted, true. Generally acceptable, false. Freedom of interpretation ceases for a concept once its polar concept (a priori validation) has been defined. "Goal induced AP" however, might be a passable stipulation for this type of problem. To keep this place from turning into a discussion forum I will discontinue comments on this issue. (2005-10-03)
paul: Author intention is: If black still can castle, his last move must have been b7-b5. However, to prove this, he has to castle (A Posteriori condition). So: 1.cxb6 e.p. axb6+ 2.Kxb6 a1R! (2...a1Q? 3.Kb7 Qxa6 mate obviously doesn`t prove b7-b5 as the last move) 3.Kb7 R1xa6 4.Rc8! and white has prevented black from castling. So black can`t prove the last move is b7-b5 and therefor is already stalemated in the initial position! (2011-07-12)
A.Buchanan: Isn't Guus' idea just AP-Prioritat? And even if it were "more logical" or "more interesting", it doesn't follow that other forms is AP are "incorrect" (2023-07-31)
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comment
Keywords: En passant as key, Castling (sg), a posteriori (AP)
Genre: Retro, Studies
FEN: r2bk3/p1Rpp3/P1p2p2/KpP2P2/1P2p3/1P6/p7/8
Reprints: (4) Problem 161-164 11/1973
317 Europe Echecs 217 01/1977
(A) Die Schwalbe 80 04/1983
408 Eigenartige Schachprobleme 2010
M36 mpk-Blätter 12/2011
Input: Gerd Wilts, 1995-06-03
Last update: A.Buchanan, 2023-07-31 more...
3 - P0000759
Luis Alberto Garaza
1034 Die Schwalbe 21 06/1973
P0000759
(9+9) cooked
Schwarz am Zug, Weiß gewinnt
1. ... fxg3ep 2. hxg3+ Kh5 3. f4 Kh6 4. h8=T+! Kg7
play all play one stop play next play all
Cook: Intended a Posteriori combo of castling and ep rights retro-locks wTh in cage, contradicting pawn capture balance
hans: only black move is fxg3e.p.
1. fxg3+ Kh5 2. h8D/T#
Why the keyword 'castling'?
Castling is illegal, for there are 7 black captures, and because white's last move is g2-g4, needs the wK let pass Rh1 (2012-05-18)
Anton Baumann: g2-g4 war nicht zwingend der letzte Zug! Schwarz ist patt, also unlösbar!
Korrektur in 'die Schwalbe' 12/2074 S.264: "wTa1 nach h1. Nun gewinnt nach 1. - fxg3 Weiss mit 2.hxg3+ Kh5 3.f4 Kh6 4.h8=T+! Kg7 und der umgewandelte Turm holt die störenden sBB ab, sodass Weiss rochieren kann und beweist, dass Schwarz nicht patt war. Schwarz versucht die Rochade zu verhindern, ist aber machtlos." (2022-12-06)
A.Buchanan: The forward play is more complicated, as Black can play more aggressively than 3. … Kh6 (2022-12-07)
Anton Baumann: Wenn Schwarz nicht 3.-Kh6! zieht, holt sich Weiss auf h8 die Dame, mit einfacherer Fortsetzung.
3.-g4? 4.f5 Kg5 (4.-g5 5.f6 ~ 6.h8=D) 5.h8=D Kxf5 6.De8 +_
3.-Kg4? 4.h8=D Kf3 5.Dxh3 g4 6.Dh2 Ke4 7.Dg2+ +_ (2022-12-09)
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comment
Keywords: Castling (wl), a posteriori (AP) (Type Petrovic), En passant as key
Genre: Retro, Studies
FEN: 8/7P/6p1/2p3p1/2p2pPk/2Pp1P1p/3PpP1P/R3K3
Input: Gerd Wilts, 1995-06-03
Last update: A.Buchanan, 2022-12-07 more...
4 - P0001420
Branko Koludrovic
294 Europe Echecs 197 04/1975
1. ehrende Erwähnung
P0001420
(13+12) C+
h#3*
1. ... cxd6ep 2. 0-0-0 0-0-0 3. Kd7 Sa7#
1. De7 c6 2. Th8 c7 3. Tf8 Sd6#
play all play one stop play next play all
White pawn caps: axb,dxe,gxf,hxg.
Black: fxg,bxc,cxb.
wPb4 came from b3 to release wBa3, so bPb3 captured to reach that square.
All pcs accounted for means bPd never captured.
In the set play, there are 13 retro tries in which one or both players do not castle. The intention is that both castling rights are needed in order to imply the pawn double hop.
A.Buchanan: White pawn caps: axb,dxe,gxf,hxg definite.
Black: fxg and two to resolve c-file. But that may be c&d cross-capture, so in set play last move might have been c6xd5. So I think this problem is cooked. What am I missing? (2022-03-21)
Mario Richter: If Black's last move was c6xd5, how do you get white Bishop a3 out of his cage? (In that case, black pawn b7 never left the b-file). (2022-03-21)
A.Buchanan: I agree Mario thanks (2022-03-21)
Hans-Jürgen Manthey: beide Rochaden und im Satz ep. ist möglich:
R.: 1. ... d7-d5 2. Sa7-b5 b5xTc4 3. Tg4-c4 Dd8-h4 4. c4-c5 Th8-h3 5. c2-c4 c4xDb3 6. Dd3-b3 h3-h2 7. Dd1-d3 h4-h3 8. Sc8-a7 h5-h4 9. Th4-g4 c5-c4 10. Th1-h4 h7-h5 11. h2xSg3 Sf5-g3 12. b3-b4 Sh6-f5 13. Lb4-a3 c7-c5 14. Ld2-b4 g3-g2 15. Lc1-d2 a3-a2 16. a2xSb3 Sc5-b3 17. Lb3-a4 Sa6-c5 18. Lc4-b3 Sb8-a6 19. d2xLe3 Lc5-e3 20. Ld3-c4 Lf8-c5 21. Lf5-d3 a4-a3 22. Lh3-f5 a5-a4 23. Lf1-h3 g4-g3 24. g2xLf3 Lb7-f3 25. Sb6-c8 Lc8-b7 26. Sa4-b6 a7-a5 27. Sc3-a4 b7-b5 28. Sb1-c3 f5xSg4 29. Se5-g4 Sg8-h6 30. Sf3-e5 e7-e6 31. Sg5-f3 f6-f5 32. Sh3-g5 f7-f6 33. Sg1-h3 (2023-02-23)
comment
Keywords: a posteriori (AP) (Type Petrovic), En passant as key, Castling (wgsg)
Genre: h#, Retro
Computer test: HC+ Popeye v4.87 & retro-logic.
FEN: r3k3/6p1/4p3/1NPp4/BPp4q/Bp2PPPr/pP2PPpp/R3K3
Input: Gerd Wilts, 1995-06-03
Last update: A.Buchanan, 2022-03-21 more...
5 - P0001937
Werner Kuntsche
6025 Schach , p. 191, 06/1969
2. Preis
P0001937
(4+12) C+
h#2
1. exd3ep Lxg4 2. f3 Le6#
play all play one stop play next play all
Klären: Quelle = Schachmatt? - Felber, Volker: SCHACH ist korrekt, 6/1969, Seite 191 (2010-10-09)

Eliminierung von 4 Steinen zwischen sK und wT im h#2 (mit Hilfe von ep-Schlag)!
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comment
Keywords: En passant as key
Genre: h#, Retro
Computer test: HC+ Popeye 4.61
FEN: 8/8/8/1pn4b/2kPpppR/2q1rB1p/1p4r1/3K4
Input: Gerd Wilts, 1995-06-03
Last update: A.Buchanan, 2023-01-09 more...
6 - P0001970
Thomas R. Dawson
26 Schachkongress Teplitz-Schönau im Oktober 1922 1923
P0001970
(13+13)
h#1
1. exf3ep Lc2#
R: 1. f2-f4 f5xTe4 2. Tg4-e4 & e.g. f6-f5 3. Tg1-g4 f7-f6 4. Le4-h7 h5-h4 5. Lg2-e4 h6-h5 6. Lf1-g2 h7-h6 7. g2xh3
play all play one stop play next play all
1.exf3e.p. Bc2# is the only possible solution, but this necessitates R: 1.f2-f4. Can we prove this?

(13+13) with 1+2 pawn captures. Bf8 captured at home, so to satisfy White appetite, the missing Black pawn (a or b) must have promoted via c2 on c1. Two more White units must be captured to allow this.

The kings cage can only be unlocked by retracting WPc2. But the clock is ticking as there are only 6 black moves which can be retracted.

The promoted piece was captured on e3 or h3. If either capture is undone, then a White bishop square is cut off, so WB must be replaced prior to this.

Now the order of the early moves is: WdP moves, WQB & WQR escape, BP promotes on c1 to X (capturing WR at some point), X captured by WP.

So the first White capture must be dxNe3 and the second White capture releases gxXh3. The second White capture releases WKB & WKR. WKR captured by original BfP.

The clock starts ticking with gxh3. Black has 6 pawn moves. WKB has 3 moves to reach h7. WR has 3 if it goes via d file, or 2 if it starts on g1 (in which case WfP or WQB must also move once). So certainly at least 6 White moves. Last move was therefore White (even if the stipulation didn't tell us), and it can only have been WfP coming from f3 or f4. If it had been coming from f3 it would have blocked WKB in its progress, so the last White move was indeed R: 1.f2-f4.

WKR did therefore move from g1-g4-e4, and R: 1. ... fxRe5 2. Rg4-e4. Prior to that, move order not unique, but counting still exact.

Note that WN loitering on b4, pretending to be part of the cage, is present on the board just to make up the numbers.
Jeliss: "Obstruction of passage square f3 to Bishop of same colour."

"Version 'Pittsburgh Leader' 08.06.1913"
Yoav Ben-Zvi: Appears as the first problem (D445) in the booklet on Dawson's RA problems by G.P. Jellis. The obstruction that occurs in the Try -1.Pf3-f4?, by WP of WB, is described as "obstruction of passage square". It is not considered by Dawson and his disciples to be a Retro opposition. Dawson's conception of RO was quite broad, it included cases where the interference was not by occupation of the target square, so the only valid reason that I can see to exclude this case is that the 2 pieces involved are both of the same color. Fabel's definition explicitly excludes "Monochrome RO". I conclude that it would be preferrable to interpret RO as a bi-chromatic interference. The keyword Retro opposition should be removed. (2018-04-07)
A.Buchanan: To my mind, RO involves some kind of parity-tempo issue between the sides, not just some kind of race-tempo. If it was just about "bi-chromatic interference", one might say that bPe4 blocks wBh7 from an immediate retreat, so it has to be wPf4 that retreats first, legitimizing the ep key. So I agree this is not RO. (2024-01-06)
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Keywords: Last Moves?, En passant as key
Genre: h#, Retro
FEN: nqb5/1rrpp1pB/KRp5/1p4B1/kN2pP1p/2P1P2P/PP2P2P/8
Reprints: D445 Retro-Opposition & Other Retro-Analytical Chess Problems 1989
Input: Gerd Wilts, 1995-06-03
Last update: A.Buchanan, 2024-01-06 more...
7 - P0002100
Adolf Norlin
v Tidskrift för Schack , p. 34, 01/1907
P0002100
(13+10)
#2
1. exf6ep+!
play all play one stop play next play all
Version in der 'Aarsskrift' 1935 innerhalb eines Artikels von K. Hannemann "Et Tema Fra den Retrograde Analyse". Im Original wDg4 statt h3 und wBh3 statt h4.
Henrik Juel: 1.exf6ep+. Not -1... a6?, requiring 3 black captures on light squares (incl. orig. Lf1); but missing orig. Lc1 was dark-squared. (2004-03-08)
Henrik Juel: C+ Popeye 4.61 and analysis (2022-06-11)
Hans-Jürgen Manthey: mögliche Zugfolge:
1. f2-f4 d7-d5 2. c2-c3 d5-d4 3. c3xd4 c7-c5 4. h2-h4 c5-c4 5. b2-b4 Lc8-d7 6. a2-a4 Ld7-b5 7. a4xLb5 Sb8-a6 8. Th1-h3 Sa6-c5 9. d4xSc5 Sg8-f6 10. d2-d4 Sf6-e4 11. c5-c6 Se4-g3 12. Lc1-d2 Se4xLf1 13. Sb1-c3 Sf1-g3 14. Sc3-a4 Sg3-e4 15. c6-c7 Ke8-d7 18. Sa4-c5+ Kd7-d6 19. Sc5-a6 Se4-c5 20. b4xSc5+ Kd6-e6 21. Ld2-a5 b7-b6 22. Sa6-b8 b6xLa5 23. Th3-e3+ Ke6-f6 24. Te3-e5 Dd8-c8 25. Dd1-d3 Dc8-a6 26. Dd3-h3 Da6-b6 27. Ta1-a3 Db6-c6 28. Ta3-g3 Dc6-d6 29. Te5-d5 Dd6-e6 30. c7-c8L De6-d6 31. Lc8-f5 Dd6-c6 32. Sg1-f3 Dc6-b6 33. Sf3-e5 Db6-a6 34. Se5-g6 Da6-b6 35. Sg6xTh8 Db6-c6 36. Tg3-g6+ h7xg6 37. Ke1-f2 Dc6-d6 38. Kf2-g3 Dd6-e6 39. Kg3-g4 De6-d6 40. Lf5-c2 Dd6-c7 41. b5-b6 Dc7-e5 42. f4xDe5+ Kf6-e6 43. Kg4-g5+ f7-f5 und nun :
1. e5xf6ep+ Ke6xTd5 2. Dh3-d7# (2023-02-24)
comment
Keywords: En passant as key
Genre: Retro
FEN: rN3b1N/p3p1p1/1P2k1p1/p1PRPpK1/2pP3P/7Q/2B1P1P1/8
Reprints: 58 Retrograde Analysis 1915
Aarsskrift DSK , p. 14, 1935
Input: Gerd Wilts, 1995-06-03
Last update: Mario Richter, 2022-06-11 more...
8 - P0003100
John Derek Beasley
Cambridge 1985
P0003100
(3+8) C+
h#2
Zeroposition
a) -sBe4
b) -sSf5
a) 1. Sg3 Kxh4 2. Le4 hxg3#
b) 1. hxg3ep Kh4 2. Lf5 hxg3#
play all play one stop play next play all
Henrik Juel: in a) last move could be Kg2-h3
in b) last move must be g2-g4 (2024-01-14)
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comment
Keywords: En passant as key, Zeroposition
Genre: h#, Retro
Computer test: HC+ Popeye 4.61 & trivial retro-logic
FEN: 8/7b/8/4pn2/4pkPp/4pp1K/7P/8
Input: Gerd Wilts, 1995-06-03
Last update: A.Buchanan, 2024-01-15 more...
9 - P0003138
Branko Koludrovic
4208 Problem 12/1979
P0003138
(11+9)
h#3 (AP)
0.1...
1. ... axb6ep 2. 0-0-0 0-0-0 3. Td7 a8=D#
play all play one stop play next play all
This problem can be solved presuming that both castlings are executable. It implies that the last halfmoves have been.-1.Bb6xa7 sBb7-b5.
Bb5 could not come from c6 (sBc6xFb5), because all of the missing white pieces(5) have been captured on white squares except wLc1,which must have been captured by Bc7(Bc7xwLb6).Further,it has not played immediately before -1.Bb6-b5 because this would prevent white castling(forcing wT or wK to move)
Here is the proof that 4 remaining white pcs have been captured on white squares:
black d-pawn must have been captured on d4 and h,g f pawns had to promote after Bh3xwFg2,then wBh2moved to h4, enabling Bg4x Fh3 ..h1T, and finnaly sBf7
after fxg2... g1S. sLf1 prevented the check from Th1, and later has been captured by a white officer.
Conclusion:
Retro:-1.wBb6xFa7 Bb7-b5
Forward(AP) 1....axb6 e. p.2.0-0-0 0-0-0 3.Td7 a8Q# (Author)
Branko Koludrovic: P.S.
The black pawn a4(on the diagramm)came from c7 after capturing the white bishop on b6, then moving to b5 and capturing a white officer on a4. (2010-09-28)
A.Buchanan: I think sBf must have captured on g2 & then promoted on f1 to S, otherwise it’s impossible to unlock the southeast cage (2023-07-11)
A.Buchanan: So that means it’s sound. However I don’t see that it needs to have been sL shielding on f1 (2023-07-11)
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comment
Keywords: a posteriori (AP), En passant as key, Castling (sgsgwg), Promotion (D), Valladao Task
Genre: h#, Retro
FEN: r3k3/P3p3/p7/Pp6/p6P/2P3PR/2PPP2b/R3K1nr
Input: Gerd Wilts, 1995-06-03
Last update: A.Buchanan, 2023-07-11 more...
10 - P0003142
Marco Bonavoglia
3652 Sinfonie Scacchistiche 01-03/1982
P0003142
(6+5) C+
h#2
b) +sTd4
a) 1. Sxb4 Sxc3 2. Ka5 Sxc4#
b) 1. cxb3ep Sc4 2. Sb4 Sxc3#
play all play one stop play next play all
Henrik Juel: In a) last move could be Kb2-a1 (2022-12-05)
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comment
Keywords: En passant as key, Cant ep, Zilahi
Genre: h#, Retro
Computer test: HC+ Popeye 4.61
FEN: 8/8/8/1P6/kPp5/N1p5/n1pP4/KN6
Input: Gerd Wilts, 1995-06-03
Last update: A.Buchanan, 2022-12-06 more...
11 - P0003189
Tivadar Kardos
2144 Diagramme und Figuren 19/09/1967
P0003189
(7+15) cooked
h#2
1. bxc3ep Lxe2 2. Sa3 0-0-0#
play all play one stop play next play all
Cook: 2. ... Td1#
Sally: Der letzte Zug war: Bc2 - c4!
Nr.138 200 Ausgewählte S .Probleme T. Kardos(W. Fentze1983) (2010-09-30)
A.Buchanan: All 9+1 captures are visible by pawns. Note R: 1. Kd1-e1 d3xe2 is illegal because it costs 2 more captures for Black. So e.p. is unconditionally legal, requiring no AP justification. I see no reason why White has lost castling rights. Indeed someone might make a demo game ending with c2-c4. So this one seems cooked. Neither WinChloe nor yacpdb contains this problem. (2022-01-08)
A.Buchanan: If this is AP, it will be rendered sound by removing wPa2. But is this the intention? Does anyone have access to the collection of selected Kardos problems mentioned? (2024-01-25)
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comment
Keywords: En passant as key, Castling (wg)
Genre: h#, Retro
FEN: 8/8/3pp3/2ppp3/1pPkrq2/4pb1P/P3p1rP/Rn2KBb1
Input: Gerd Wilts, 1995-06-03
Last update: A.Buchanan, 2022-01-08 more...
12 - P0003194
Tivadar Kardos
1597 Schachmaty 05/1963
P0003194
(6+14) C+
h#2
1. cxd3ep? bxc3 2. Lxf4 Lxg2# Last move not d2-d4
1. gxf3ep! bxc3 2. Lf4 Lf5# Last move f2-f4
play all play one stop play next play all
White's last move was certainly one of the two double pawn hops. The last move couldn't be d2-d4 because Black's pawns had already captured 10 of White's pieces, and playing d2-d4 would have resulted in wBc1 being White's 17th piece. So, the only solution is 1.gxf3 e.p.
Viktoras Paliulionis: The last move couldn't be d2-d4 because Black's pawns had already captured 10 of White's pieces, and playing d2-d4 would have resulted in wBc1 being White's 17th piece. So, the only solution is 1.gxf3 e.p. (2023-12-30)
A.Buchanan: Yes that's right! (2023-12-31)
comment
Keywords: En passant as key
Genre: h#, Retro
Computer test: HC+ Popeye C-Version 4.87 & trivial retro-logic
FEN: 2n1q3/5prp/5K1b/3b4/2pPkPp1/2p1p1pB/1P4pP/8
Reprints: 546 FIDE Album 1962-1964 1968
Input: Gerd Wilts, 1995-06-03
Last update: A.Buchanan, 2023-12-31 more...
13 - P0003206
Hans Joachim Schlüter
4443v Schach , p. 349, 11/1963
P0003206
(5+8)
h#2
b) wTf1 tauschen mit wLg1
a) 1. Kxb4 Lb6 2. a4 Tb1#
b) 1. cxb3ep gxf3 2. Sc1 Tg4#
play all play one stop play next play all
Korrektur 1964, Seite 155: sBh3->f3
Henrik Juel: C+ Popeye 4.61 (2022-11-24)
comment
Keywords: En passant as key
Genre: h#, Retro
FEN: 8/8/8/p7/kPp5/p1p2p2/4n1Pp/5RBK
Input: Gerd Wilts, 1995-06-03
Last update: Felber, Volker, 2022-11-24 more...
14 - P0003207
Klaus Gerber
4497 Schach , p. 30, 01/1964
P0003207
(4+9) C+
h#3
1. exf3ep c3 2. Df7 Ke4 3. Dh5 exf3#
play all play one stop play next play all
A.Buchanan: Can shift bQd5 to c4, while replacing bRg5 with bP to reach Meredith status. bBh4 can also be downgraded to bP. But probably even more economy is possible by shifting pieces one file to the right, keeping the ep, White tempo & model mate, which seem to be the main features (2022-11-30)
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comment
Keywords: En passant as key
Genre: h#, Retro
Computer test: HC+ Popeye 4.61
FEN: 8/8/8/3q2r1/2p1pPkb/4K1pp/2PrP3/8
Input: Gerd Wilts, 1995-06-03
Last update: A.Buchanan, 2022-11-30 more...
15 - P0003240
Gabor Tar
Magyar Sakkelet 06/1972
P0003240
(4+10) C+
h#2
b) sLe3 nach f3
a) 1. f3 Lxa7 2. Lg5 Lxf2#
b) 1. fxg3ep Lxc7 2. Lh5 Ld8#
play all play one stop play next play all
Henrik Juel: a) C+ Popeye 4.61
b) the ep capture is unjustified, last move could be Ke2-f1 or f3xg4 (2023-08-06)
A.Buchanan: There was an error in the stipulation: "b) sLe3 nach h2 (-wSh2)" is completely incorrect. However "b) sLe3 nach f3" leads to a very nice problem which matches the solution already present. This problem is not in WinChloe, but I am sure this is the resolution of the mystery (2023-08-07)
Henrik Juel: You are probably right, Andrew; maybe there was a misprint in the source
Now part b) is C+ Popeye 4.61 after very simple analysis (2023-08-07)
comment
Keywords: En passant as key
Genre: h#, Retro
Computer test: HC+ Popeye v4.61 & simple retro-logic for b)
FEN: 1B6/npp5/8/8/5pPk/4b2p/3p1p1N/5Kn1
Input: Gerd Wilts, 1995-06-03
Last update: A.Buchanan, 2023-08-07 more...
16 - P0003337
Rudolf Buljan
Problem 41-44 03/1957
2. Preis
15. Thematurnier
P0003337
(11+15) C+
h#2
1. ... exf6ep 2. Sf5 f7#
play all play one stop play next play all
White captured fxg and promoted [Pd2] on d8
Black captured axbxa2-a1=Y, b7xc6, d5xe4, and gxf
White cannot have moved last, and in fact Black's last move can only have been f7-f5 in order to give White a prior move. R: 1... d5-e4 would have retro-blocked wPd marching to its promotion.
So the retroplay was R: 1... f7-f5 2.f5xYg6
Numerous retro tries but none distinct.
"Autor Ing. Rudolf Buljan, Zagreb"
AB: Have therefore marked him in the author table as Croatian. Yugoslavia has been removed from the PDB country list, I see.
A.Buchanan: Any ideas how to distinguish usage of “whose move?” and “no legal last move for white” (or black) keywords (2020-10-01)
Henrik Juel: This problem is clearly the latter
I would use 'Whose move?' in retro problems where a deeper analysis is required to determine the move, often with stipulations like '#1 (who?)' (2020-10-01)
A.Buchanan: I think "Whose move?" is where there is no forward stip, or where we have to determine if the forward stip should be interpreted as orthodox or as half-duplex. "no legal last move for..." is where the mater/stalemater/etc is the usual one, but we add or remove a single move at the beginning of the forward stip. I guess a third possibility is "last move?" where in a Type A position we also have to figure out who moved last.
With respect, I don't think the level of analysis can be relevant. (2023-12-06)
more ...
comment
Keywords: En passant as key, No legal last move for White
Genre: h#, Retro
Computer test: Popeye 4.61
FEN: 5nkb/1qp1p1n1/2p3PQ/4PpKb/4prRp/P4prB/1PP3PP/8
Input: Gerd Wilts, 1995-06-03
Last update: A.Buchanan, 2023-12-06 more...
17 - P0003365
Gyula Bebesi
41 Problemas 04-06/1962
P0003365
(8+14) cooked
h#2
1) 1. axb3ep bxc6+ 2. b5 cxb6ep#
2) 1. exd3ep g8=D,L+ 2. d5 cxd6ep#
play all play one stop play next play all
PRA: 1 solution with 2 parts
Henrik Juel: White captured [sLc8] on c8 and axb, so last move was either b2-b4 or d2-d4
C+ Popeye 4.61, except for the promotion dual (2020-08-03)
A.Buchanan: There's no keyword for an untolerated dual promotion! (2020-08-03)
Henrik Juel: Yes and no, Andrew
What about the cooked label? (2020-08-03)
A.Buchanan: Hi Henrik: this is obviously intentional. I tried to replace the pawn promotion with wDh8-h7+ but I ran out of pieces. I guess that Bebesi had the same difficulty. The word "cooked" seems too strong to me, but it's obviously a significant defect though (2020-08-04)
A.Buchanan: The bar is higher for helpmates than other problems, and this is unsound. However it’s not cooked but dualled. Yet all we have is “cooked” so I suppose it is in PDB-speak. I’ve added that and removed the 2.1… (2023-08-07)
Joost de Heer: Is there an 'unsound' keyword? (2023-08-07)
A.Buchanan: Hi Joost: no there isn't. It can be added, the challenge for any new common keyword would be populating it for more than a few values. (2023-08-07)
A.Buchanan: This time round, I've managed to find a fix. Bebesi's correction in WinChloe 66992 has non-standard wL. I have a feeling I've seen a similar one by Andrey Frolkin & someone else recently with a different matrix, and also non-standard wL. I've sent my effort to Joaquim Crusats at Problemas for his assessment (2023-08-08)
more ...
comment
Keywords: En passant as key (2), Partial Retro Analysis (PRA), En passant as mating move (2), Superseded by (P1411659, P1413906)
Genre: h#, Retro
FEN: 3qn3/1p1p2P1/B1r3p1/1PP1Kp2/pPkPp3/p1p4n/N7/2b5
Reprints: 233 Ungarische Schachproblem Anthologie , p. 188, 1983
1 Problemas 44, p. 1456, 10/2023
Input: Gerd Wilts, 1995-06-03
Last update: A.Buchanan, 2023-12-04 more...
18 - P0003366
Laszlo Lindner
3040v Europe Echecs 07-08/1982
P0003366
(8+16)
h#2
b) sBc7 nach f6
a) 1. Dc4 Lxb6+ 2. c5 dxc6ep#
b) 1. fxe3ep Lxb4 2. Sc4 bxc3#
play all play one stop play next play all
Lindner in 'Mattbilder eines Lebens':
In a) ist die Lösung der stellung b) nicht möglich, weil das e.p.-Schlagen durch Schwarz nicht legal ist. Der letzte Zug von Weiß muß nicht unbedingt e2-e4 geweseb sein. Es kommt als letzter zug auch Kh3-g2 in Betracht, mit den vorherigen Zügen h4:g3 e.p.+ und g2-g4.
In b) demgegenüber sind Kh3-g2 und vorher f4:g3 e.p. illegal, weil die Rücknahme von g2-g4 unmöglich ist: der sB würde 7 Schlagfälle benötigen, und es fehlen nur 6 weiße Steine. Der letzte weiße Zug muß also e2-e4 gewesen sein.
In 'Mattbilder eines Lebens' abgedruckt mit sTh7 statt h8 und der Quellenangabe: Europe Echecs, 1964
AB: (1) Where is wK?
(2) Why is 1.fxe3ep legal in b) but not a)? (2002-01-31)
Henrik Juel: wK is probably on g2. In part a) last move could have been Kh3-g2, I think (2002-02-01)
A.Buchanan: Very convincing, Henrik. I've repaired the diagram accordingly. (2023-05-28)
comment
Keywords: En passant as key, En passant in the retro play
Genre: h#, Retro
FEN: 7r/2pn4/1nqRb3/B2Pp3/pb1kPp2/2p2Pp1/1PP2pKp/7r
Reprints: 501 Mattbilder eines Lebens , p. 379, 1996
Input: Gerd Wilts, 1995-06-03
Last update: Mario Richter, 2023-05-28 more...
19 - P0003817
Jean Oudot
Nation Belge 1956
P0003817
(14+12) C+
#2
1. cxd6ep
play all play one stop play next play all
paul: Since the wB couldnt leave c1, the captured piece on b6 is the promoted wPh2. If last black move was f7-f5, then h-Pawn captured four pieces to promote on d8, among which bRh8, impossible. Thus, the h-Pawn could only have been promoted from f7 and therefore d7-d5 remains as the last move. (2011-07-02)
more ...
comment
Keywords: En passant as key
Genre: Retro, 2#
Computer test: C+ Popeye 4.61
FEN: qrRNkb2/PpQ1p1pp/1pp1R3/2PpKpP1/6N1/7B/1P1PPP2/8
Reprints: RA15 diagrammes 15 06/1975
(51) Mat Plus 12 10-12/2009
Input: Gerd Wilts, 1995-06-03
Last update: A.Buchanan, 2022-11-27 more...
20 - P0004479
Matjaz Zigman
Länderkampf Mazedonien-Slowenien 1969
6. Platz
P0004479
(10+13) C+
ser-h#5* (AP)
* 1. ... Lxd2#
1. dxe3ep 2. Txf2 3. Txg2 4. Th2 5. Th3 0-0#
play all play one stop play next play all
more ...
comment
Keywords: Castling (wk), Seriesmover, En passant as key, a posteriori (AP) (Type Petrovic)
Genre: Retro, Fairies
Computer test: HC+ Popeye 4.61 after analysis
FEN: 8/8/8/4pPp1/1p1pPkpb/1P1P2p1/pPpr1PP1/rbB1K2R
Reprints: 103 Bilten 1970 1971
(70) Problem 144-147 12/1971
Input: Gerd Wilts, 1995-06-03
Last update: A.Buchanan, 2023-07-20 more...
21 - 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)
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...
22 - P0540829
Filippo Minieri
H551 The Problemist 07-08/1977
P0540829
(5+9) cooked
h#2
1.2.1.1
1) 1. exd3ep b8=D 2. Kd4 Df4#
2) 1. exd3ep a8=S 2. d4 Sxb6#
play all play one stop play next play all
Cook: e.p. not justified as R: 0.e3xd4 possible
VL: Unjustified ep-capture because of –e3xd4. For correction it suffices e.g. to add bSe3.
This is possibly a unique 2-move helpmate with ep-key and 2 solutions of the type 1.2.1.1 (at least so currently in the PDB).
Publi?ation details. H551 in the Helpmate section of the July issue, with no preview. Here is the text of the solution published in the Nov.-77 issue: “…White may have just played P(e3)xd4. Very few solvers have spotted this. Full marks for claim of no solution with correct reasoning but, in fairness, one mark for composer's intention. White cannot have just played K(a5)a6 in reply to Pxb6+ as too many captures by Black are required.” (2023-12-01)
A.Buchanan: Yes Valery you are right this must be cooked. However, I'm not a fan of +bSe3 because it spoils one of the model mates. Separately, I mildly prefer bPf7 to bPe6. (2023-12-03)
VL: I do prefer bPf7, as well. I don't see any way to save at least one of the properties Kindergarten Problem and Model mate (2) after fixing (what for these keywords have been added just now?). Besides, Andrew, please, refine the specification ((full) number and publication month 07-08). (2023-12-03)
A.Buchanan: Ok have added the publication details. The keywords are useful to indicate the aim, even though the problem is cooked. I guess there is a way to keep the model mates but it’s very clunky and probably +bSe3 is better (2023-12-03)
more ...
comment
Keywords: En passant as key, Kindergarten Problem, Model mate (2)
Genre: h#, Retro
Computer test: (Popeye C-Version 3.52 (2048 KB))
FEN: 8/PP6/Kpp1p3/2pp4/1pkPp3/2p5/P7/8
Input: Michal Dragoun, 1998-04-09
Last update: A.Buchanan, 2023-12-03 more...
23 - P1000662
Gianni Donati
R074 Probleemblad 11/1999
P1000662
(10+14) C+
h#1.5 (AP)
1. ... gxh6ep 2. exf1=L 0-0-0#
play all play one stop play next play all
Kommentare:
Als einziger letzter schwarzer Zug, der die weiße Rochade
erhält, kommt nur Bh7-h5 infrage, was dem Weißen den e.p.-Schlag
ermöglicht, um nicht die Rochade oder das Mattnetz zerstören zu
müssen (H.P.Suwe)
Gianni Donati: This intends to show the Valladao theme in the minimum number of moves. (2004-03-19)
VL: The waiting ep capture. Cf. also P1000260
(by T.Petrovic, 2000) somewhat enriched
thematically with the illegal try 2... Rd1#??. (2004-06-03)
A.Buchanan: The “illegal try” 2. Rd1+ is not actually mate because c2 is unprotected. This is kind of “logic dual” spoils the A.P. motivation for the castling (2020-05-20)
Henrik Juel: White captured h6xg7 and once more, e.g. axPb-b8=Y
Black captured cxdxe, dxexf, fxg, and once more, e.g. a2xb1=Y
Possible retroplay 1... h7-h5 2.h6xSg7 Df8-f4 3.h5-h6 Sf4-h3 4.Sh3-g1 etc., preserving the castling right
Any other black last move would force White to retract Ta1, as d2xc3, d2xe3, and h6xh7 would be illegal retractions
I agree with Andrew that the double motivation of 2... 000# is a weakness:
a. legitimizing h7-h5
b. mating (2020-05-21)
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)
A.Buchanan: See discussion at P0009121 (2023-08-04)
more ...
comment
Keywords: a posteriori (AP), En passant, En passant as key, Castling, Valladao Task, Promotion (l)
Genre: Retro
Computer test: HC+ Popeye v4.87 + simple retro logic
FEN: 6n1/4p1P1/6p1/6Pp/2b1rqrb/2PkPppn/1P2pP2/R3KRN1
Reprints: König & Turm (4), p. 28, 03/2001
H Problemkiste (143) 10/2002
(V2) Problemkiste 156 12/2004
Input: Gerd Wilts, 2000-08-01
Last update: A.Buchanan, 2023-08-03 more...
24 - P1012015
Henri Nouguier
Jean-Claude Gandy
Jean Claude Dumont

diagrammes 1975
Lob
P1012015
(12+8) C+
#2
1. Sg5? droht 2. Sxf7#
1. ... f5!

1. dxc6ep! droht 2. Kb6#
1. ... bxc6+ 2. Kxc6#
play all play one stop play next play all
Le Fnf1 provient de la promotion du PNh7 (2 prises) après capture à domicile du Fbf1 (1 prise). bxc5, dxc5 ou dxe6 comme dernier coup N sont à rejeter puisqu'ils nécessiterait 2 prises supplémentaires. Le RN n'a pu venir de d6 au coup précédent car cela impliquerait exf8:F+ comme dernier coup B. Dans ce cas les PB auraient effectué 9 prises or il ne manque que 8 PN. Le RN n'a pu venir de f4 ou de f5 après fxe4 car la position des PB e2, f3 et g2 rendrait inexpli- cable la présence simultanée de la TB en f2 et du FN en f1. Le PNe6 ne vient pasde e7 car le FB n'aurait pu accéder à f8 et le PNc5 ne vient pas de c6 à cause de l'+ non paré au RB.
No. 1111 HN
Correction of P0003822
A.Buchanan: Odd that the correction has fewer composers than the cooked original (2023-05-27)
HENRI: To be corrected :
The third author Jean-Claude Dumont must be add as mentioned in the award 1975-1976 page 539 diagrammes n° 31 jan - feb 1978. (2023-05-30)
more ...
comment
Keywords: En passant as key
Genre: Retro
Computer test: HC+ Popeye 4.61 and (french) analysis
FEN: 5B2/1p3ppN/4p3/RKpPk3/3pP3/3P2P1/2P1PRP1/5b2
Input: Henri Nouguier, 2004-01-11
Last update: A.Buchanan, 2023-05-30 more...
25 - P1012052
Henri Nouguier
diagrammes 2004
P1012052
(9+15)
shc#6
1. dxc3ep 2. Kxb5 3. Kc6 4. Kd7 5. Ke8 6. 0-0 Txg7#
play all play one stop play next play all
Un des PNd a pris 1 pièce blanche. pour venir de e7. Donc les PB b, c et d ne peuvent se croiser. Le PBg6 ne peut venir de f5 car il faudrait 2 prises noires! Seule reste le dernier coup blanc 0... c2-c4 Ceci implique que le FNb1 est issue de promtion ! C'est le PNb7, il aurait pris 2 pièces blanches. Les PNg5 et h5 ont pris 2 pièces blanches.
No. 11661 HN
A.Buchanan: “Obvious promotion” is intended to refer to something visible in the initial diagram position, not what is reached during series play (2022-09-14)
A.Buchanan: Similarly “non-standard material (2022-09-14)
more ...
comment
Keywords: Seriesmover, Consequent, En passant as key, Promotion in the retro play (sLb1), Castling, Valladao Task
Genre: Retro, Fairies
FEN: 7r/5pnR/5PnR/1Pp2ppq/1kPp4/p2P4/P2pP3/Kbb4r
Input: Henri Nouguier, 2004-01-11
Last update: Mario Richter, 2022-09-14 more...
26 - P1012536
Thomas R. Dawson
British Chess Magazine 06/1925
P1012536
(10+5) cooked
#2
Grashüpfer d5,d6
1. b8=S? droht 2. Sc6#
1. ... Gxa6!

1. bxc6ep! Gxd4,Gxb6,~ 2. Lb5#

R: 1. c7-c5 2. Gd7-d5+ Gb8-d6
play all play one stop play next play all
'The Problemist', p. 241, 09/1993: "The solution to this #2 with Grasshoppers is 1.bxc6
en passant. lf Black's last move had been 1...c6, then White's previous move would have been the illegal G(d7)-d5+.
Cook: 1. Sc4+ Kxa4 2. Sab6#
No. 2251 HN
A.Buchanan: Diagram error? Solution typo? (2023-01-06)
Mario Richter: Diagram error corrected (2023-01-07)
Ulrich Voigt: NL: 1. Sc4+ Kxa4 2. Sab6# (2023-01-08)
Mario Richter: Vielleicht sind Dawson und alle, die diese Aufgabe unkritisch nachgedruckt haben, einer typischen Halluzination erlegen: im Geiste nimmt man den Zug c7-c5 zurück, der erst den ep-Key ermöglicht, und meint dann, daß die NL: 1. Sc4+ Kxa4 2. Sab6 an 2. ... c7xb6 scheitert ... (2023-01-09)
A.Buchanan: Easily repaired e.g. by replacing wSa8 with wLa7 (2023-01-09)
comment
Keywords: En passant as key
Pieces: du = Grasshopper (G)
Genre: Retro, Fairies
FEN: N2K4/1P6/PN1*2q4/kPp*2Q4/Pp1R4/p2B4/8/8
Reprints: The Problemist , p. 241, 09/1993
Input: Henri Nouguier, 2004-01-11
Last update: A.Buchanan, 2023-01-09 more...
27 - P1020144
Josef Kling
23 The Chess Euclid 1849
P1020144
(6+6)
#2
1. axb6ep+ Kb1 2. 0-0#
1. ... Da7 2. Kf2#
play all play one stop play next play all
in 'Le Pion' fälschlich wBa4 ("1 - R 1 R ... 5 - P 4 TD ...")

Nach heutigen Konventionen ist der Ep-Schlag unzulässig, man beachte aber:
Kling im 'Chess Euclid' zur Intention dieser Aufgabe: "This problem I have compossed expressly to shew the error the modern composers of problems have committed, in introducing the system of castling in the ends of games. In this problem I consider I have as good a reason to say that Black has just moved his Q. Kt. P. [b5] two squares as that White has not moved his K. R. or K."
James Malcom: I found this hidden ancient, another that rode the rails of the unjustified en passant key. (2020-12-28)
SP: Unsound in its own terms, as, whatever Black plays (Kb1/Qa7),
castling is never forced due to 2.Kf2#
I use the keyword "non-analytic en passant key" for such problems. (2023-08-21)
A.Buchanan: The composer's stated intention seems to be that (1) ep is ok (2) castling is not ok. In these terms, the problem is sound (2023-08-22)
comment
Keywords: Brian Stephenson Collection (4985), En passant as key, Castling (wk), En passant, Castling as mating move, Golden Age
Genre: 2#
FEN: R7/7q/7r/Pp6/5p1r/7P/4Q3/k3K2R
Reprints: 458 Dubuque Chess Journal 35 01/1873
P10 Le Pion 01/05/1873
Input: Brian Stephenson, 2004-08-12
Last update: A.Buchanan, 2023-08-22 more...
28 - P1095638
Andrej W. Borodulin
Sportklub Bogatyr Kriwoj Rog 1988
Spezielle ehrende Erwähnung (im Russ. Turnier)
P1095638
(12+6) C+
s#5
Zuletzt geschah zwingend e7-e5.
1. dxe6ep dxe6+ 2. Kf4 Ld7 3. c8=S+ Lxc8 4. Th8 Ld7 5. Td8 e5#
play all play one stop play next play all
more ...
comment
Keywords: Multiple publication, En passant as key, Stalemate dissolution
Genre: s#, Retro
Computer test: A. Baumann: Gustav 4.2a
FEN: 2b5/1pPp4/1P1k1P2/1B1PpKPR/1P2P1p1/4B1P1/8/8
Reprints: S1246 The Problemist 01/1989
6657 Die Schwalbe 08/1989
Input: Frank Müller, 2009-12-07
Last update: A.Buchanan, 2024-01-04 more...
29 - P1107661
M. Leclercq
L'Echiquier de Paris 1953
G. Authier gewidmet
P1107661
(10+4)
#2
1. dxe6ep
play all play one stop play next play all
Henrik Juel: C+ Popeye 4.61 and very simple analysis (2022-11-16)
more ...
comment
Keywords: En passant as key
Genre: Retro
FEN: 5kn1/5p2/3N1PRP/1B1PpKB1/4RN2/8/8/8
Reprints: (10) Mat Plus 12 10-12/2009
Input: Gerd Wilts, 2010-06-13
Last update: Rainer Staudte, 2022-11-16 more...
30 - P1201388
Arthur Poplawski
Deutsche Schachzeitung , p. 319, 10/1888
P1201388
(15+14) C+
#2
1. e5xd6ep+
1. ... e5 2. Taxf7#
1. ... f6 2. Dxf6#
1. ... Kxf8 2. Dh8#
play all play one stop play next play all
'DSZ': "Die untenstehende Stellung theilt uns ein Herr A. P. in Zürich zur Veröffentlichung mit. Wir möchten jedoch noch an das Diagramm für unsere Löser eine Warnungstafel anhängen, wie man solchen häufig in zoologischen Gärten begegnet: 'Achtung, ich beisse!"
Henrik Juel: Black captured [Lc1] with an officer, and the black pawns never captured. White captured d3xLe4 and f2xSg3, so all seemingly possible last moves by Black fail because of an illegal check, except d7-d5.
1.exd6ep+ f6/Kxf8 2.Dxf6/Dh8# (2011-09-04)
Ladislav Packa: 1.-e5 2.Raxf7# (2011-09-04)
A.Buchanan: Why not R: 1. Kf6-g7 d4xe5+ (2020-07-05)
Kevin Begley: You can not legally retract -1.Kf6-g7 d4xe5+, when you consider the only two units black is missing are a light-squared bishop and a knight. The Knight must have been captured on g3 (light squared bishop can not die there). Nor can black's light-squared bishop have been captured on e5. (2020-07-05)
A.Buchanan: I shouldn't post before breakfast (2020-07-05)
Lutz Neweklowsky: The chess problem is o.k. , because the last 2 moves were : 1.fxNg3 Bf3e4 2.dxBe4 d5 and 3.e5xd6ep+ cheers Lutz Neweklowsky (2023-06-10)
more ...
comment
Keywords: En passant as key
Genre: 2#, Retro
FEN: 1n3R2/R3ppkp/p1N3Br/rpKpP1pP/q1p1P2N/1PQ3P1/P1P3Pb/8
Input: Mario Richter, 2011-08-27
Last update: Mario Richter, 2021-03-26 more...
31 - P1233676
Sergio Orce
5421 Problemkiste (136) 08/2001
P1233676
(12+10)
#2
(RV)
b) wBb3->b4
a) 1. Ke6! (0-0-0 illegal!) ... 2. h8=D,T#
b) 1. dxe6ep! 0-0-0 2. Dxb7#
oder 1. Ke6 ... 2. h8=D,T#
play all play one stop play next play all
a) 0-0-0 ist illegal. Die wBB haben 5-mal geschlagen, wBBf3/h3 also nicht.
-> sBf2h2 haben 3-mal geschlagen, entweder 3-mal auf schwarz oder nach Rücknahme von g2-g4
-> Lf1 ist nicht unter den Schlagopfern.
-> wBa2 mußte umwandeln. Falls 0-0-0 noch gehen soll, muß die UW auf h8 geschehen sein
-> letzter Schlagfall W×S ist sowieso klar
-> sBa7 muß als Schlagfall für wB dienen. Da e5 es selbst nicht kann, muß er umgewandelt haben, kann dazu aber nur wLf1 schlagen
-> Widerspruch. -> 0-0-0 ist illegal.
b) dito, aber es geht sBa7-a4xLb3-b1 usw.
-> 0-0-0 ist legal. Aber nur, wenn zuletzt e7-e5.
-> 1. dxe6ep, oder falls zuletzt sK/sT-Zug 1. Ke6.
-> "Retrovarianten" (RV) wohl besser als "A posteriori" (AP)
(Übersetzung, Anmerkung und Prüfung durch Hans Gruber).
A.Buchanan: The retro content here is fun, but I don't see why it's suggested that this is AP. (a) is a cant castler, and (b) is a standard PRA matrix. Removing AP as a keyword for this one. (2023-07-21)
comment
Keywords: Valladao Task, Castling, En passant as key, Partial Retro Analysis (PRA)
Genre: Retro, 2#
FEN: r3k3/1pp4P/3p2N1/2NPpK2/4QpP1/1P3PRP/4Pp1p/6n1
Input: Erich Bartel, 2012-03-04
Last update: A.Buchanan, 2023-07-21 more...
32 - P1248622
Oleksiy I. Borisenko
1674 Zadachi i etyudy 01-04/2003
2. ehrende Erwähnung
P1248622
(9+3)
s#5
b) -wBg2
a) 1. hxg6ep+ Kh5 2. Dd1+ Kh6 3. Dh5+ Kxh5 4. g4+ Kh6 5. f4 hxg6#
b) 1. Dd1 g4 2. Dh1+ g3 3. f4 g2 4. Dxg2 Kxh5 5. Dg6+ hxg6#
play all play one stop play next play all
Anton Baumann: Retro: Warum soll Dxc1+ g7-g5 illegal sein?
s#5: a) & b) C+ Gustav 4.2a (2024-02-05)
Henrik Juel: You are right, Anton
The keyword 'No legal last move for Black' should be deleted (2024-02-05)
comment
Keywords: En passant as key, No legal last move for Black
Genre: s#, Retro
FEN: 8/7p/4NB1k/4PKpP/4P3/8/5PP1/2Q5
Input: Frank Müller, 2012-09-16
Last update: A.Buchanan, 2017-10-04 more...
33 - P1255845
Bernd Schwarzkopf
13750 Die Schwalbe 231 06/2008
P1255845
(2+3)
#6
Längstzüger
1. cxd6ep! g5 2. d7 Kg7 3. d8=D Kh6 4. Kg4 Kg7 5. Kf5 Kh6 6. Dh8#
play all play one stop play next play all
Anton Baumann: Retro: Unter der Annahme, dass die Längstzügerregel auch für den der Diagrammstellung vorangegangenen Zug gilt, kann der letzte Zug nur d7-d5 gewesen sein! Daher die Lösung:
1.cxd6 e.p.! g5 2.d7 Kg7 3.d8=D Kh6 4.Kg4 Kg7 5.Kf5 Kh6 6.Dh8# (2022-09-14)
comment
Keywords: Maximummer, Kindergarten Problem, Minimal, Miniature, En passant as key
Genre: Fairies
FEN: 7k/6p1/8/2Pp4/8/6K1/8/8
Input: Gerd Wilts, 2012-12-13
Last update: Mario Richter, 2022-09-14 more...
34 - P1299824
Georgi Hadzi-Vaskov
Länderkampf Mazedonien-Slowenien 1969
4. Platz
P1299824
(9+6) cooked
ser-h#10
1. bxc3ep 2. cxb2 3. Kc3 4. Kc2 5. Kc1 6. b1=T 7. Tb2 8. Kb1 9. Ka1 10. Txa2 0-0#
play all play one stop play next play all
Cook: 1. a3 2. axb2 3. b1=S 4. b3 5. Kc3 6. Kb2 7. Ka3 8. Ka4 9. Sa3 axb3#
Anton Baumann: cook: 2 Lösungen in 9 Zügen: 1.a3 sowie 1.b3
1.a3 2.axb2 3.b1=S 4.b3 5.Kc3 6.Kb2 7.Ka3 8.Ka4 9.Sa3 axb3# (mit ZU) (2020-05-11)
more ...
comment
Keywords: Seriesmover, En passant as key, a posteriori (AP) (Type Petrovic), Castling (wk)
Genre: Fairies, Retro
FEN: 8/8/1P6/PRP5/ppPk4/3pp2p/PP6/4K2R
Reprints: 101 Bilten 1970 1971
Input: Frank Müller, 2015-03-22
Last update: A.Buchanan, 2023-04-06 more...
35 - P1321497
Pal Benko

P1321497
(5+5) C+
#2
1. axb6ep cxb6+ 2. Sxb6#
1. ... Sxc8,Sxc6 2. b7#
play all play one stop play next play all
In 'My Life' steht als Originalquelle "Games 1996" - welche Publikation damit gemeint ist, ist unklar. In den Index-Files des 'Games and Puzzle Journal' [Jelliss] taucht der Name Benkö nicht auf, laut 'Chess Periodicals' [Felice] gab es zwar einige Magazine, die vom Namen her passen könnten (s. S.90ff, Einträge 1016ff), deren Publikationszeitraum aber jeweils weit vor 1990 endet.

Figurenkranz 3×4 a5c8
Henrik Juel: C+ by Popeye 4.61
Strategems started in 1998, I believe (2016-06-19)
Frank Müller: Die Quelle kann ich auch nicht prüfen. es könnte auch The Games and Puzzles Journal sein. Das gab es zumindest in 1996. (2016-06-19)
Mario Richter: Vielleicht kann jemand mit Zugriff auf alte 'Strategems'-Ausgaben mal schauen, was dort als Originalquelle zu Problem P1000507 angegeben ist - das könnte helfen ... (2016-06-20)
James Malcom: As far as I can see it, it does not appear in the archived issues of The Games and Puzzles Journal: http://www.mayhematics.com/p/p.htm (2021-01-03)
Anton Baumann: vergl. P1402037 (2023-05-15)
comment
Keywords: En passant as key, Symbol problem
Genre: 2#, Retro
Computer test: Popeye 4.61 + analysis
FEN: kbN5/n1p5/B1N5/PpK5/8/8/8/8
Reprints: 284 My life, games and compositions 2003
Input: Mario Richter, 2016-06-19
Last update: A.Buchanan, 2023-05-15 more...
36 - P1343579
Kjell Widlert
9771 FEENSCHACH 817-820 07-09/1970
P1343579
(6+9) C+
h#2
Circe
1. ... gxh6ep[+sBh7]! 2. Dxg4[+wBg2] Sxg4[+sDd8]#
1. Sf3? gxh5[+sBh7] 2. Dg4 Sxg4[+sDd8]#
R: 1. h7-h5 2. Sf3xBh2[+sBh7]
play all play one stop play next play all
Five retro tries h#2 but not distinct:
1.Sh4-f3 g4*h5[+bPh7] 2.Qh3-g4 Sh2*g4[+bQd8] #
1.Sh4*g6[+wPg2] g2*h3[+bQd8] 2.h5*g4[+wPg2] Sh2*g4[+bPg7] #
1.Sh4*g6[+wPg2] g4*h5[+bPh7] 2.Qh3-g4 Sh2*g4[+bQd8] #
1.h5*g4[+wPg2] g2*h3[+bQd8] 2.Sh4-f3 Sh2*g4[+bPg7] #
1.h5*g4[+wPg2] g2*h3[+bQd8] 2.Sh4*g6[+wPg2] Sh2*g4[+bPg7] #
Klären ob Originalforderung h#2
Alfred Pfeiffer: Originalforderung war h#2. In der Lösungsbesprechung (fs-1, 01/1971, S.17) steht: "Korrekterweise sollte bei Aufgaben dieser Art ein Hinweis gegeben werden, daß sie Retroanalyse erfordern!".
Bei der Scheinlösung hat weiß keinen letzten Zug. (2017-11-23)
Henrik Juel: Giving a hint about retro analysis would spoil the fun (2017-11-23)
A.Buchanan: Quite right Henrik. Solvers should always be on their toes (2023-12-07)
comment
Keywords: Circe, En passant as key, No legal last move for White
Genre: Fairies, Retro, h#
Computer test: laut WinChloe
FEN: 8/8/6P1/6Pp/6Pn/4P1pq/3prk1N/4bb1K
Input: HBae, 2017-11-23
Last update: A.Buchanan, 2023-12-07 more...
37 - P1401495
Igor Vereshchagin
Odessa 1997
Special commendation
P1401495
(10+14) C+
h#2 (AP)
1. a4xb3ep+ Sxa5+ 2. Kd5 0-0-0# (by AP not Td1#?)
R: 1. b2-b4 Kb4-c4+ 2. Sd6-b7,Sd6xLc7
play all play one stop play next play all
With the typo wPd5 corrected to e5, the two forward candidate solutions are correct. How about the retro? Assume that White castling rights remain. bBg5 is promoted, and did so on c1 or g1. In either case, there were 6 pawn caps by Black, but in the former case, the blockaded wRh was not consumable. So the promotion must have been on g8, and White can't retract h2-h3. The missing White unit is light B, so was not just captured on e5 or b4. wRf6 is promoted, say wPd, which would have involved no captures.

This leaves b2-b4, preceded by Kb4-c4+ and before that Sd6-b7. Prior to b2-b4, why couldn't bQ have just played e.g. Qa8-a5+ instead? Because there would still be no prior move: wSb7 can't have just come from h5 or e6. Similarly Rc3-a3 has no precedent.

We don't know exactly what happened to sLc, but that doesn’t affect the soundness. It might have enabled wPc or wPd to capture. wPd did promote, but maybe it was wPc that after capturing promoted to T. Alternatively, Sd6xLc7 was possible.
Henrik Juel: Popeye 4.61 with 'opt enp b3' found no solution (2022-05-27)
Gerald Ettl: Schaut so aus, als ob die sDa5 nach e5 muss. 1.axb3 ep Sa5+ 2.Kxd5 0-0-0# (2022-05-27)
Gerald Ettl: aber auch 2.-Td1# ? (2022-05-27)
Henrik Juel: Andrew, can you throw any light on this problem? (2022-05-28)
Henrik Juel: Gerald, in AP problems like this one White must castle to legitimize the ep capture key (2022-05-28)
A.Buchanan: Hi Henrik, Gerald. I found this one in WinChloe with the current diagram. It gave the "solution" 1. axb3ep+ Sxa5+ 2. Kd5?? 0-0-0#. However when I tried running the WinChloe solver just now, it said there's no solution. Quite right: Rf5 controls d5. I don't think we can shift Qa5 to e5 though.
My first thought is that wPd5 should be on e5. Check my suggested solution in the solution text. However, as you will see, I think we need a second thought as well! Hope the finest retro minds can figure this out. Failing that, we could ask Igor. (2022-05-28)
Mario Richter: The diagram in the reprint in 'Uralsky Problemist' is exactly as given here. The solution given there without further explanation is: 1. ab+ (e.p.) Sxa5+ 2. Kd5 0-0-0#!
Notice that the second black move doesn't contain a capture sign!

Some typos in Andrew's analysis:
The black potential promotion squares should be c1 and g1.
White's last move couldn't have been b3-b4?? simply because that would give an illegal check. (2022-05-28)
A.Buchanan: Thanks Mario for the careful reading. I’ve fixed the errors. Pd5 may be a typo in the reprint then. It also creates a bogus retraction d4-d5, so I don’t think it can be right. Now for Igor. (2022-05-29)
A.Buchanan: Joaquim Crusats spotted R: 1. b2-b4 Kb4-c4+ 2. Sd6-b7, which I'm sure is the intended retraction. So we diagnose a single typo that occurred in the Uralsky reprint diagram: wPe5 appeared on d5. I suggest correcting it here. (2022-05-30)
A.Buchanan: Author confirmed this was a typo (2022-11-23)
more ...
comment
Keywords: a posteriori (AP) (Type Petrovic), En passant as key, Castling (wg), Promotion (Tl), Valladao Task
Genre: h#, Retro
Computer test: Once the diagram typo was fixed, C+ Popeye v4.87 & basic but tricky retro logic
FEN: 3n4/1Np1p1p1/4pn2/q1p1PRb1/pPk1pr2/r6P/P4PP1/R3K3
Reprints: 18 The Ural's Problemist 13, p. 5, 02/1998
Input: A.Buchanan, 2022-05-27
Last update: A.Buchanan, 2022-05-30 more...
38 - P1404274
Gyula Breyer
Magyar Sakkvilag 31/05/1919
P1404274
(14+15)
Weiß zieht und setzt nicht matt
1. bxc6ep!

Auflösung Dr. Jenö Bán:
R: 1. ... c7-c5 2. Kd7-e6 Df7-e8 3. Kc6-d7 Ke5-e4 4. Sd2-f1 Lg7-f8 5. Sf2-h1 Da2-f7 6. Tf8-f3 Sa4-c3 7. f7-f8=T Ke6-e5 8. f6-f7 Kf7-e6 9. f5-f6 Db1-a2 10. f4-f5 Lf5-d3 11. Kd5-c6 Tg8-b8 12. Kc4-d5 Tb8-b7 13. La8-g2 Lh6-g7 14. Df1-h3 Lg7-h6 15. Tg1-g3 Lh6-g7 16. Th1-g1 Dd1-b1 17. Sh3-f2 Ke8-f7 18. Sg1-h3 Sc5-a4 19. a7-a8=L Lc8-f5 20. a6-a7 Sf7-h8 21. a5-a6 Th8-g8 22. a4-a5 Ta8-b8 23. a2-a4 Sa6-c5 24. Kc3-c4 a5xTb4 25. Tb1-b4 Lf8-h6 26. Ta1-b1 f5xLg4 27. Sb1-d2 d2-d1=D 28. Dd1-f1 d3-d2 29. Le1-h4 Sh6-f7 30. Ld2-e1 f7-f5 31. Lc1-d2 Sg8-h6 32. Kd2-c3 g7-g6 33. Ke1-d2 Sb8-a6 34. b4-b5 a7-a5 35. b2-b4 b7-b6 36. d2xDe3 Dd4-e3 37. f2-f4 Dd8-d4 38. Lh3-g4 d4-d3 39. Lf1-h3 d5-d4 40. g4-g5 d7-d5 41. g2-g4
play all play one stop play next play all
Schwarz schlug axb und fxg, der weiße Doppelbauer e2e3 erfodert eine weißen Schlag, damit sind alle fehlenden Steine erklärt. Der fehlende sBd7 mußte schlaglos auf d1 umwandeln, bevor er geschlagen werden konnte, also stammt wBe3 von d2, und die wBBa2 und f2 haben auf a8 bzw. f8 umgewandelt, bevor sie geschlagen wurden. Nur zuletzt R: 1. ... c7-c5 verhindert das weiße Retropatt, also ist der ep_Schlüssel legal.
Henrik Juel: 1.bxc6ep
R: 1... c7-c5 2.Kd7-e6 Df7-d8+ 3.Ke6-d7 Dg7-f7+ 4.Kd7-e6 Ke5-e4 etc. (2022-09-11)
comment
Keywords: En passant as key
Genre: Retro
FEN: 1r2qb1n/1r2p2p/1p2K1p1/1Pp3P1/1p2k1pB/2nbPRRQ/2P1P1BP/5N1N
Reprints: Gyuala Breyer - The Chess Revolutionary [ed. Jimmy Adams] , p. 807, 2017
Input: Mario Richter, 2022-09-11
Last update: Mario Richter, 2022-09-11 more...
39 - P1406456
Werner Keym
OP016 The Hopper Magazine I02 25/06/2022
corrects Keym Schach-Echo 1967 / Die Schwalbe 2007
P1406456
(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)
play all play one stop play next play all
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 ...
comment
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...
40 - P1406941
Marco Bonavoglia
Best Problems 105, p. 561, 01/2023
P1406941
(4+4)
h#2 a Posteriori
Ultrapatrouilleschach
1. dxe3ep 0-0-0+! 2. Kf7 d8=S#

R: 1. e2-e4
play all play one stop play next play all
Autor: "Le ultime mosse sono state del Re bianco (protetto dalla Ta1) o Be2-e4 protetto dal Ke1. Il nero prende en passant e il bianco deve giustificarlo a posteriori arroccando. Tema Valladao of course." [Zuletzt zog der weiße König (geschützt durch Ta1) oder Be2-e4 geschützt durch Ke1. [mri: oder Td1-a1] Schwarz schlägt en passant und Weiß muss es anschließend durch die Rochade rechtfertigen. Valladao-Thema natürlich.]
Posthum innerhalb eines Nachrufes auf Marco Bonavoglia veröffentlicht.

Antonio Garofalo: "Marco, mentre era in ospedale, mi ha inviato questi due problemi, uno augurale, l'altro per la competizione fairies. Sfortunatamente egli non può vedere i suoi lavori pubblicati, essendo deceduto nelle prime ore del 5 dicembre 2022..." [Marco schickte mir, während er im Krankenhaus war, diese beiden Probleme [dieses und P1406940], eines für seine [Neujahrs-]Wünsche (P1406940), das andere für den Wettbewerb, Abteilung Märchenschach. Leider kann er seine veröffentlichten Werke nicht mehr sehen, denn er verstarb in den frühen Morgenstunden des 5. Dezember 2022.]
Joost de Heer: C+ Popeye with 'opt enp e2e3e4'.
Too bad there isn't a try without castling. (2023-04-04)
comment
Keywords: En passant as key, Ultrapatrol, Valladao Task
Genre: h#, Retro, Fairies
Computer test: laut 'Best Problems' C+, aber Prüfprogramm nicht angegeben
FEN: 4k2r/3P4/2n5/8/3pP3/8/8/R3K3
Input: Mario Richter, 2022-12-30
Last update: Mario Richter, 2022-12-30 more...
41 - 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 ...
comment
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...
42 - P1410414
O. Kirnberger
17 Grafinger Zeitung 03/07/1932
P1410414
(7+8)
#4
1. gxh6ep+! Kf7 2. 0-0+ Df4 3. Txf4+ Ke6 4. Tf6#
3. ... Kg8 4. Sdf6#
Co-Dual 2. Tf1+ Df4 3. Txf4+ Ke6 4. Tf6#
3. ... Kg8 4. Sdf6#
play all play one stop play next play all
Originaldiagramm war verdruckt, Korrektur 17.07.1932

'Grafinger Zeitung': "... eine Aufgabe aus unserm Leserkreise, die sich Schachgebote zum Motto wählte.
Jägerlatein.
Der Bauer auf dem fünften Feld,
Das ist in diesem Kampf der Held!"

Der ep-Schlüssel ist retroanalytisch nicht begründbar.
Henrik Juel: So the problem is incorrect, I think (2023-06-18)
comment
Keywords: En passant as key
Genre: n#
FEN: rq2bb1n/6k1/2P3p1/3N2Pp/6N1/1B6/8/4K2R
Input: Mario Richter, 2023-06-18
Last update: Mario Richter, 2023-06-18 more...
43 - P1411659
Gyula Bebesi
v Problemas 1962
P1411659
(8+14) cooked
h#2
1. exd3ep Lg8+ 2. d5 cxd6ep#
1. axb3ep bxc6+ 2. b5 cxb6ep#
play all play one stop play next play all
PRA means one problem two parts
Cook: R: 1. Kf6-e5 Ld6-f8+
see P0003365
Henrik Juel: Intention:
White captured axSb and [Lc8]
If last move was b2-b4: 1.axb3ep bxc6+ 2.b5 cxb6ep#
If last move was d2-d4: 1.exd3ep Lb8+ 2.d5 cxd6ep# (2023-08-08)
Henrik Juel: Cook: last move could also be Kf6-e5
correction, e.g., move Sh3 to h5 (2023-08-08)
A.Buchanan: Good catch Henrik - I should have looked at this one more carefully! Luckily it admits an easy fix, but there is still the non-standard material. (2023-08-08)
Henrik Juel: I should have thought of a better birthday greeting, Andrew, but there you are (2023-08-08)
comment
Keywords: Partial Retro Analysis (PRA), En passant as key (2), En passant as mating move (2), Non-standard material (L), Superseded by (P1413906)
Genre: h#, Retro
Computer test: HC+ Popeye v4.87 & simple retro-logic
FEN: 3r1b2/1p1p3B/B1r3p1/1PP1Kp2/pPkPp3/p1p4n/N7/2q5
Reprints: Schach-Echo , p. 324, 08/1984
23 125 ausgewählte Schachprobleme , p. 10, 1985
2 Problemas 44, p. 1456, 10/2023
Input: A.Buchanan, 2023-08-08
Last update: A.Buchanan, 2023-12-04 more...
44 - P1413906
Andrew Buchanan
3 Problemas 44, p. 1456, 10/2023
after Gyula Bebesi
P1413906
(11+14) C+
h#2
1. axb3ep bxc6+ 2. b5 cxb6ep#
1. exd3ep Dxg8+ 2. d5 cxd6ep#
play all play one stop play next play all
Wh captures axb, XxLc1.
Bl captures cxb/dxc, hxg, gxh/f and either fxe or wBe is waylaid. So the position is legal, with Wh last move being pawn double hop. In particular wKf6-e5 was not the last move

PRA, last move was either b2-b4 or d2-d4. So there is "one solution with two parts".
See P0003365 (cooked) & P1411659 (fixably cooked but non-standard thematic material).
This new version has an obvious promoted unit (non-thematic), but Joaquim Crusats (a noted constructor) could not find any way to do better
Ladislav Packa: Mr. Bebesi's first name is Gyula (not Gyulia). It is the Hungarian version of the name Julius. (2023-12-05)
A.Buchanan: Thanks - edited (2023-12-06)
more ...
comment
Keywords: Partial Retro Analysis (PRA), Obvious promotion (l), En passant as key (2), En passant as mating move
Genre: h#, Retro
Computer test: HC+ Popeye 4.61
FEN: 3rn1bQ/1p1p2PR/B1r3pP/1PP1K2n/pPkPp3/b1p5/N7/2q5
Reprints: SuperProblem (Website) 06/12/2023
Input: A.Buchanan, 2023-12-04
Last update: A.Buchanan, 2023-12-06 more...
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