Author: Uri Blass
Date: 03:03:37 02/12/04
Go up one level in this thread
On February 12, 2004 at 04:48:26, martin fierz wrote:
>On February 11, 2004 at 20:40:17, scott farrell wrote:
>
>>this is from a game on ICC crafty vs chompsterx
>>
>>I think Robert is using his cct6 quad opteron, and chompster wins due to a
>>blunder by crafty.
>>
>>in this position crafty plays rxh3, will a huge scores favouring black (crafty
>>v19.3 analysis), and when white plays Rh2 it then changes the score to like +4
>>for white, a swing of about a queen.
>>
>>It took crafty 2:40 (2 mins 40 secs) and 17 ply to see the fail low (on a dual
>>PIII 1.26 v19.3).
>>
>>[d] 8/7p/8/4pp1k/8/r6P/P5R1/6K1 b - - 0 41
>>
>>
>>[Event "ICC 5 3"]
>>[Site "Internet Chess Club"]
>>[Date "2004.02.11"]
>>[Round "-"]
>>[White "ChompsterX"]
>>[Black "crafty"]
>>[Result "1-0"]
>>[ICCResult "Black resigns"]
>>[WhiteElo "2572"]
>>[BlackElo "2709"]
>>[Opening "Bishop's opening: Berlin defense"]
>>[ECO "C24"]
>>[NIC "IG.04"]
>>[Time "19:55:16"]
>>[TimeControl "300+3"]
>>
>>1. e4 e5 2. Bc4 Nf6 3. d3 Nc6 4. Nc3 Bb4 5. Bd2 O-O 6. Nd5 Bxd2+ 7. Qxd2 Nd4
>>8. c3 b5 9. cxd4 bxc4 10. dxe5 Nxd5 11. exd5 cxd3 12. Qxd3 d6 13. Nf3 Rb8
>>14. O-O Rxb2 15. Qd4 Rb5 16. Qd3 Rb6 17. Rfe1 dxe5 18. Nxe5 Bb7 19. Rad1 Rd6
>>20. Qa3 Bxd5 21. Qxa7 Bxg2 22. Rxd6 cxd6 23. Kxg2 Qg5+ 24. Kh1 dxe5 25. Qc5
>>f6 26. Qd5+ Kh8 27. Rg1 Qf4 28. Qb7 g6 29. f3 Rd8 30. Qe4 Qxe4 31. fxe4 Rd3
>>32. Re1 Rf3 33. Kg2 Ra3 34. Re2 Kg7 35. h3 Kh6 36. Kh2 Kg5 37. Rg2+ Kh4 38.
>>Rg4+ Kh5 39. Rg2 f5 40. exf5 gxf5 41. Kg1 Rxh3 42. Rh2 Rxh2 43. Kxh2 e4 44.
>>a4 Kg4 45. a5 e3 46. Kg2 f4 47. a6 f3+ 48. Kf1 Kg3 49. a7 e2+ 50. Ke1 h5 51.
>>a8=Q h4 52. Qb8+ Kg4 53. Qc8+ Kf4 54. Qh3 Ke4 55. Qxh4+ Ke3 56. Qe7+ Kd3 57.
>>Kf2 e1=Q+ 58. Qxe1 Kd4 59. Kxf3 Kc4 60. Qa5 Kb3 61. Kf4 Kb2 62. Qb4+ Ka1 63.
>>Ke4 Ka2 64. Kf4 {Black resigns} 1-0
>
>for all those who immediately see that white wins after ...Rxh3?? Rh2 with their
>passed pawn race code, check this minor modification (i gave black one tempo
>more)
>
>[D]8/7p/8/5p1k/4p3/r6P/P5R1/6K1 b - -
>
>this time it's black who wins after ...Rxh3 Rh2. you might want to check that
>position to see whether your pawn race code is correct in this case too.
>
>for me, this is another of these extremely sharp positions, where a single tempo
>decides about win or loss - i suspect that many evals will be confused by this,
>as it is basically only decidable by search. but perhaps you guys can prove me
>wrong?
>
>cheers
> martin
The main point is that programs should not evaluate unclear position as winning.
Black has a big advantage without capturing the pawn so there is no reason to
capture h3 and get unclear pawn endgame.
evaluating Rxh3 Rh2 as a win for white without search is a msitake but
evaluating it as a win for black is also a mistake that cause Crafty to miss a
simple win by not capturing the pawn.
Uri
Uri
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