Author: Robert Hyatt
Date: 15:08:13 11/15/01
Go up one level in this thread
On November 15, 2001 at 07:16:14, Uri Blass wrote: >On November 15, 2001 at 06:51:23, José Carlos wrote: > >>On November 15, 2001 at 03:35:23, Dieter Buerssner wrote: >> >>>The end position in this game is >>> >>>[D] 8/8/6p1/6Q1/2K4p/6kP/5p2/8 b - - 0 55 >>> >>>How does your engine evaluate this pos? >>> >>>[Event "?"] >>>[Site "Beersheba ,CBM 09"] >>>[Date "1988.??.??"] >>>[Round "?"] >>>[White "Kortchnoi, V."] >>>[Black "Rechlis, G."] >>>[WhiteElo "2640"] >>>[BlackElo "2475"] >>>[ECO "A15"] >>>[Result "1/2-1/2"] >>> >>>1. Nf3 Nf6 2. c4 g6 3. Nc3 d5 4. cxd5 Nxd5 5. g3 Bg7 6. Bg2 >>>O-O 7. O-O c5 8. Qa4 Nc6 9. Qc4 Nxc3 10. bxc3 b6 11. Qh4 >>>Bb7 12. Rb1 e6 13. c4 Qxh4 14. Nxh4 Rab8 15. Nf3 Nb4 >>>16. Bb2 Rfd8 17. Bxg7 Kxg7 18. Rb2 Rd6 19. d3 Re8 20. a3 >>>Na6 21. Ra1 e5 22. Nd2 Bxg2 23. Kxg2 f5 24. a4 Nb4 25. a5 >>>Re7 26. f3 h5 27. h3 Kf6 28. axb6 axb6 29. Ra8 Rdd7 30. Rb1 >>>Ra7 31. Ra1 Nc6 32. Nb1 Rxa1 33. Rxa1 Ra7 34. Rxa7 Nxa7 >>>35. Nc3 Ke6 36. Nd5 b5 37. Nc7+ Kd7 38. Nxb5 Nxb5 39. cxb5 >>>Kc7 40. f4 exf4 41. gxf4 h4 42. Kf2 Kb6 43. Ke3 Kxb5 >>>44. Kd2 Kb4 45. Kc2 c4 46. Kb2 cxd3 47. exd3 Kc5 48. Kc3 >>>Kd5 49. d4 Ke4 50. Kc4 Kxf4 51. d5 Kg3 52. d6 f4 53. d7 f3 >>>54. d8=Q f2 55. Qg5+ 1/2-1/2 >> >> This is the kind of position programs can chose the right moves, but don't >>understand at all. My program says +7.xx for white, but it defends correctly >>with black. >> I guess this position won't be solved by any program in a long time because it >>requires reasoning. You can't write code for positions like this easily, because >>an extra pawn here or there makes a difference. So you have to 'think'... the >>magic word. > > >I am not sure that this position will not be solved by search > >I suspect that it is also possible to see forward enough to see a forced >repetition or tablebase position so it is possible that tablebases can help. > >Based on the post that I read they did not help but maybe the poster did not >give the programs enough time. > > The word that puts distance between GM's and programs. GM's can, >>given enough time, understand _any_ position. > >I doubt it > > And if they misunderstand one and >>lose, the next game he'll have learned the lesson. Computers can't do such a >>thing. > >Humans may learn not to lose by similiar way but it is possible that the >position included a very complicated tactics and the GM's learned to avoid one >mistake only to do another mistake. > >Uri As a human, I simply ask the question "is there any place for the king to hide to escape from the checks?" If the answer is no, I assume repetition. I've also seen this happen a lot of times. Someone played Crafty a game the other night (I will try to find the PGN) using some version of Chess Tiger. Crafty's eval steadily went down until it hit about -4.5 or so. Tiger made a move and my eval went to 0.00 and stayed, and it happened instantly. I don't know whether Tiger forward pruned a move that led to the repetition, or whether it just got lost in all the checks. But it does happen, and humans solve it in a far different way than computers do. IE I certainly don't search 60+ plies to determine that the king can't escape. :)
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