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| Johan Christoffel van Gool, André Chéron; Journal de Genève, 1977. Código FEN: 1K1n2q1/1p4pR/1prPPpPn/1RB1p1rP/8/1B2p3/2p2b2/1k2N3 w - - 0 1. |
As Brancas jogam e dão xeque-mate em 69 lances! Este problema é famoso por um motivo: até hoje, é o mais longo problema de mate direto já composto, com a solução atendendo às restrições de só ter xeques e não ter duais.
(White to play and give checkmate in 69 moves! This problem is famous for one reason: until today, it is the longest direct mate problem ever composed, with the solution meeting the restrictions of only having checks and having no duals.)
PCFilho
The solution is all-checking, so the key move must be a check. The possible options are these discovered checks:
ResponderExcluir1. Ba4+ (a move that allows ... Ka2)
1. Ba2+ (a sacrifice that doesn't bring any compensation)
1. Bc4+
1. Bd5+
1. Bxc2+ (a move that allows ... Ka2)
Só, my candidates are Bc4+ and Bd5+
Good beginning: one of these candidates is the key move. :)
ExcluirI'm enjoying these problems a lot, because the softwares just can't figure them out. And we can!! :)
ExcluirChess softwares are now very strong players. However, they fight with the so-called "horizon effect" (and lose). When it comes to seeing far far away, our brains still beat them, sometimes.
ExcluirAt least for now...
For those who don't know the "horizon effect": it happens when the number of possible continuations is immensely huge, and chess softwares cannot feasibly search them all.
ExcluirChess softwares are still mostly based on "brute force search": they just test as many continuations as they can, to choose "the best one". Together with opening libraries and previously-calculated endgame tablebases, this is enough for winning normal chess games against human beings.
However, it's not enough for solving these tricky long problems. :)
Thank you for the explanation. Is there any top chess software online that we can run from the web browser? I would like to see what they would do with this 69-mover.
ExcluirThe program I have on my PC is totally lost. 😂
Este comentário foi removido pelo autor.
ResponderExcluirDisclaimer: I saw the solution somewhere. Anywho, here it is.
ResponderExcluirFirst, a few preliminary moves which include a knight sacrifice:
1 Bc4+! Kc1 2 Ba3+ Kd2 3 Bb4+ Kc1 4 Sd3+ Kd1 5 Sxf2+ exf2
Now, the dark-squared bishop gets to work clearing away stuff:
6 Rd5+ Kc1 7 Ba3+ Kb1 8 Rb5+ Ka1 9 Bb2+ Kb1 10 Bd4+ Kc1 11 Be3+ Kd1 12 Rd5+ Ke1 13 Bd2+ Kd1 14 Bxg5+ Ke1 15 Bd2+ Kd1 16 Bb4+ Kc1 17 Ba3+ Kb1 18 Rb5+ Ka1 19 Bb2+ Kb1 20 Bxe5+ Kc1 21 Bf4+ Kd1 22 Rd5+ Ke1 23 Bd2+ Kd1 24 Bb4+ Kc1 25 Ba3+ Kb1 26 Rb5+ Ka1 27 Bb2+ Kb1 28 Bxf6+ Kc1 29 Bg5+ Kd1 30 Rd5+ Ke1 31 Bd2+ Kd1 32 Bb4+ Kc1 33 Ba3+ Kb1 34 Rb5+ Ka1 35 Bb2+ Kb1 36 Bxg7+ Kc1 37 Bxh6+ Kd1 38 Rd5+ Ke1 39 Bd2+ Kd1 40 Bf4+ Ke1
Now, it's the light-squared bishop's turn to play wrecking ball:
41 Re5+ Kd1 42 Be2+ Ke1 43 Bg4+ Kf1 44 Bh3+ Kg1 45 Rg5+ Kh1 46 Bg2+ Kg1 47 Bxc6 Kf1 48 Bb5+ Ke1 49 Re5+ Kd1 50 Be2+ Ke1 51 Bg4+ Kf1 52 Bh3+ Kg1 53 Rg5+ Kh1 54 Bg2+ Kg1 55 Bxb7+ Kf1
And now, with the seventh rank cleared, White walks the black king back to the queenside for the mate:
56 Ba6+ b5 57 Bxb5+ Ke1 58 Re5+ Kd1 59 Be2+ Ke1 60 Bc4+ Kd1 61 Rd5+ Ke1 62 Bd2+ Kd1 63 Bb4+ Kc1 64 Ba3+ Kb1 65 Rb5+ Ka1 66 Bb2+ Kb1 67 Ba2+ Kxa2 68 Ra7+ Kb1 69 Ra1