Computer Chess Club Archives


Search

Terms

Messages

Subject: Re: can ANY program play Q endgames properly?

Author: Eugene Nalimov

Date: 19:58:02 09/17/99

Go up one level in this thread


If everything will go right, on Monday I'll have KQQKQQ ready.

Eugene

On September 17, 1999 at 22:51:22, Richard Bean wrote:

>it looks like kasparov has blundered with 45.Ke4,
>allowing the following continuation:
>
>1. e4 c5 2. Nf3 d6 3. Bb5+ Bd7 4. Bxd7+ Qxd7 5. c4 Nc6 6. Nc3 Nf6 7. O-O g6
>8. d4 cxd4 9. Nxd4 Bg7 10. Nde2 Qe6 11. Nd5 Qxe4 12. Nc7+ Kd7 13. Nxa8 Qxc4
>14. Nb6+ axb6 15. Nc3 Ra8 16. a4 Ne4 17. Nxe4 Qxe4 18. Qb3 f5 19. Bg5 Qb4
>20. Qf7 Be5 21. h3 Rxa4 22. Rxa4 Qxa4 23. Qxh7 Bxb2 24. Qxg6 Qe4 25. Qf7
>Bd4 26. Qb3 f4 27. Qf7 Be5 28. h4 b5 29. h5 Qc4 30. Qf5+ Qe6 31. Qxe6+ Kxe6
>32. g3 fxg3 33. fxg3 b4 34. Bf4 Bd4+ 35. Kh1 b3 36. g4 Kd5 37. g5 e6 38. h6
>Ne7 39. Rd1 e5 40. Be3 Kc4 41. Bxd4 exd4 42. Kg2 b2 43. Kf3 Kc3 44. h7 Ng6
>45. Ke4 Kc2 46. Rh1 d3 47. Kf5 Nh8 48. g6 d2 49. g7 d1=Q 50. Rxd1 Kxd1
>51. gxh8=Q b1=Q+
>
>now the problem is, the PV in crafty always has a 5-man draw
>in it, yet the evaluation is about +3 for White.
>
>even with the Peter Karrer modifications to evaluate.c:
>---begin mods---
>  if (drawn_ending > 0) return(DrawScore(root_wtm==wtm));
>  score=Material;
>  if (Material == -100) score = 0; /* new */
>  if (Material == 0) score = -200; /* new */
>
>The first line ensures that white will evaluate its position as
>positive, preventing it from trading down to (EGTB) draws.
>
>Second line gives a penalty of two pawn equivalents for capturing a
>black pawn. This avoids silly things such as 51.Qc8 followed by
>52.Qxb7 in ending D.
>---end mods---
>
>Now crafty *still* has White capturing both pawns at 23 ply, leading to an egtb
>draw - eval still > +2.
>
>Are there any modifications possible to make *any* program
>evaluate this as a draw, which it certainly seems to be?  there is just check
>after check in the PV...
>
>(of course, many thanks to Robert Hyatt & Eugene Nalimov for
>writing the programs in the first place!)



This page took 0 seconds to execute

Last modified: Thu, 15 Apr 21 08:11:13 -0700

Current Computer Chess Club Forums at Talkchess. This site by Sean Mintz.