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4 problem(s) found in 6547 milliseconds (displaying 4 problem(s)). [COMMENTDATE>=20220810 AND G='Retro' AND NOT K='x Steine schlagen auf ein Feld' AND A='Wereschtschagin, Igor A.'] [download as LaTeX]

1 - P1066749
Igor Vereshchagin
Rustam Ubaidullajew

Retros mailing list 25/09/2004
2. Lob Sommerturnier 2003
P1066749
(10+12) C+
BP in 13,0
1. Sc3 d5 2. Sxd5 Dxd5 3. Sf3 Dxa2 4. Tg1 Db1 5. Txa7 Dxc1 6. Txa8 Da1 7. Txb8 Da7 8. Da1 Dxf2+ 9. Kd1 Dxf1+ 10. Se1 Dxg1 11. Da8 Da7 12. Sf3 Da2 13. Sg1 Db1#
play all play one stop play next play all
Henrik Juel: Natch 3.1 did not find the solution in 2 hours (2018-12-19)
Moldenhauer: Computerprüfung: C+ Stelvio 1.0 30:26:23 Stunden. 3250955 Strategien.
Keine Lösung: BP 12.0, BP 12.5.
C+ Euclide 1.11 98:10:54 Stunden. (2023-02-15)
comment
Keywords: Unique Proof Game
Genre: Retro
Computer test: Stelvio 1.0
FEN: QRb1kbnr/1pp1pppp/8/8/8/8/1PPPP1PP/1q1K2N1
Input: Gerd Wilts, 2004-09-30
Last update: Silvio Baier, 2023-03-03 more...
2 - P1394897
Andrey Frolkin
Igor Vereshchagin

WCCC Rhodes 10/2021
4th Prize Champagne-TT A
P1394897
(11+14) C+
BP in 19.0
1. a4 g5 2. a5 g4 3. a6 g3 4. axb7 a5 5. b4 Ta6 6. b5 Tg6 7. b6 Sa6 8. b8=S gxh2 9. Sc6 Txg2 10. Sxe7 Sxe7 11. b7 Thg8 12. b8=S T8g7 13. Sc6 Sxc6 14. e4 Df6 15. e5 Df3 16. e6 f5 17. e7 Kf7 18. e8=T Lc5 19. Td8 Sxd8
play all play one stop play next play all
Moldenhauer: Computerprüfung: C+ Stelvio 1.11 11 Sekunden.
Keine Lösung: BP 18.0, BP 18.5.
Notation: 1.a4 g5 2.a5 g4 3.a6 g3 4.axb7 a5 5.b4 Ta6 6.b5 Tg6 7.b6 Sa6 8.b8=S gxh2
9.Sc6 Txg2 10.Sxe7 Sxe7 11.b7 Thg8 12.b8=S T8g7 13.Sc6 Sxc6 14.e4 Df6 15.e5 Df3
16.e6 f5 17.e7 Kf7 18.e8=T Lc5 19.Td8 Sxd8 (2023-05-09)
comment
Keywords: Unique Proof Game, Homebase (w), Champagne-TT (2021)
Genre: Retro
Computer test: Stelvio 1.11
FEN: 2bn4/2pp1krp/n7/p1b2p2/8/5q2/2PP1Prp/RNBQKBNR
Input: A.Buchanan, 2021-10-25
Last update: Silvio Baier, 2023-11-14 more...
3 - P1394899
Andrey Frolkin
Igor Vereshchagin

WCCC Rhodes 10/2021
2nd HM Champagne-TT A
P1394899
(14+11) C+
BP in 11.0
1. a4 g5 2. a5 g4 3. a6 g3 4. axb7 a5 5. b4 Ta6 6. b5 Tg6 7. b6 Sa6 8. b8=S gxh2 9. Sc6 Txg2 10. Sxe7 Sxe7 11. b7 Thg8 12. b8=S T8g7 13. Sc6 Sxc6 14. e4 Df6 15. e5 Df3 16. e6 f5 17. e7 Kf7 18. e8=T Lc5 19. Td8 Sxd8
play all play one stop play next play all
A.Buchanan: Can someone post the A-to-B 1st HM by Per Olin, please (2021-10-25)
Moldenhauer: Computerprüfung: C+ Stelvio 1.11 1 Sekunde.
Keine Lösung: BP 10.0, BP 10.5.
Notation: 1.f4 Sf6 2.f5 Sd5 3.f6 h5 4.fxe7 h4 5.exd8=T+ Ke7 6.b4 Ke6
7.b5 Le7 8.b6 Txd8 9.bxa7 b5 10.axb8=S Lb7 11.Sxd7 Txd7 (2023-05-09)
comment
Keywords: Unique Proof Game, Homebase (w), Champagne-TT (2021), Schnoebelen Theme (T)
Genre: Retro
FEN: r7/1bprbpp1/4k3/1p1n4/7p/8/P1PPP1PP/RNBQKBNR
Input: A.Buchanan, 2021-10-25
Last update: Silvio Baier, 2023-11-14 more...
4 - 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...
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The problems of this query have been registered by the following contributors:

Gerd Wilts (1)
A.Buchanan (3)