Author: Uri Blass
Date: 10:24:45 09/18/01
Go up one level in this thread
On September 18, 2001 at 12:22:20, Robert Hyatt wrote: >On September 18, 2001 at 10:53:39, Uri Blass wrote: > >>On September 18, 2001 at 10:45:15, José Carlos wrote: >> >>>On September 18, 2001 at 09:56:32, Ed Schröder wrote: >>> >>>>On September 18, 2001 at 09:40:26, Eduard Nemeth wrote: >>>> >>>>>First the game: >>>>> >>>>>[Event "TCh-YUG Herceg Novi YUG"] >>>>>[Site "?"] >>>>>[Date "2001.??.??"] >>>>>[Round "?"] >>>>>[White "Vukic,M"] >>>>>[Black "Marinkovic,I"] >>>>>[WhiteElo "2470"] >>>>>[BlackElo "2440"] >>>>>[ECO "A30"] >>>>>[Result "1-0"] >>>>> >>>>>1. Nf3 Nf6 2. g3 b6 3. Bg2 Bb7 4. O-O g6 5. c4 c5 6. Nc3 >>>>>Bg7 7. d4 cxd4 8. Qxd4 d6 9. Be3 Nbd7 10. Rac1 Rc8 11. b3 >>>>>O-O 12. Qd2 Nc5 13. Rfd1 Nce4 14. Nxe4 Nxe4 15. Qe1 Qd7 >>>>>16. Nd4 Nf6 17. Nf3 Ne4 18. Qb4 Nc3 19. Rd2 Ne4 20. Rd3 Nc5 >>>>>21. Rdd1 Rfd8 22. Ne1 h5 23. Bxc5 Rxc5 24. Nd3 Bxg2 >>>>>25. Kxg2 Qb7+ 26. f3 Rc7 27. Nf2 Rdc8 28. Qd2 b5 29. cxb5 >>>>>Qxb5 30. Kf1 Bc3 31. Qd3 Qa5 32. Rc2 Bf6 33. Rdc1 Rxc2 >>>>>34. Rxc2 Rxc2 35. Qxc2 d5 36. e3 Kg7 37. Nd3 e6 38. Ke2 Qa3 >>>>>39. f4 Kg8 40. h3 Kg7 41. Kf3 Qd6 42. g4 hxg4+ 43. hxg4 e5 >>>>>44. fxe5 Bxe5 45. Nxe5 Qxe5 46. Qc5 Qf6+ 47. Kg3 Qe5+ >>>>>48. Kh3 a6 49. Qd4 Kf6 50. b4 Ke6 51. a4 Qc7 52. g5 Qc2 >>>>>53. Qf6+ Kd7 54. Qxf7+ Kd6 55. Qf6+ Kd7 56. Qd4 Ke6 57. Kg3 >>>>>Qb1 58. Qb6+ Ke7 59. Qb7+ Kf8 60. Qxd5 Qxb4 61. Qd8+ Kg7 >>>>>62. Qd4+ 1-0 >>>>> >>>>>Position after move 61. Kg7: >>>>> >>>>>[D]3Q4/6k1/p5p1/6P1/Pq6/4P1K1/8/8 w - - >>>>> >>>>>After 62. Qf6+ is the win not easy. But after 62. Qd4+ is the game easy to win, >>>>>and the game end! For any programs ist the move Qd4+ not easy to find. >>>>> >>>>>:-( >>>> >>>> >>>>I am sure all Rebel programs find this instantly. A simple chess rule says: >>>>"one pawn up in a pawn ending wins". >>>> >>>>Ed >>> >>> Are you serious Ed? In this position, it's a clear win, but in most pawn >>>endgames, you have to calculate a lot, or otherwise know some rules (which names >>>I don't know how to translate from spanish to english) to figure if it's a win >>>or not. >>> >>> Maybe you were simply joking, and I didn't catch it... :) >> >>In most pawn endgames one pawn advantage is enough to win the game. >>It is not something that always happens but computer can safely evaluate >>+2 for positions with one pawn advnatage if they do not see a positional >>advantage for the side that has less pawns. >> >>Uri > > >I believe that if humans discover this "rule" in Rebel, it will die a slow >and painful death on ICC. I can create _many_ positions where the rule is >wrong. And if I can do it, GMs will do it. Happened to me many times. I >was burned by going into simple king and pawn endings where I was a pawn up, >but my opponent had a distant majority. And he would win. And win. Note that I said that computers can safely evaluate +2 if they do not see a positional advantage for the side with less pawns. Having a distant majority is a positional advantage. I also think that Ed is right and today search solves usually the problem of missevaluating pawn majority. Here is an example that I composed: New position [D]6rk/1p6/8/8/p7/6R1/P4PPP/7K w - - 0 1 Analysis by Deep Fritz: 1.Rxg8+! +- (2.97) Depth: 1/2 00:00:00 1.Rxg8+! Kxg8 +- (5.63) Depth: 1/3 00:00:00 1.Rxg8+ Kxg8 2.Kg1 +- (5.63) Depth: 2/5 00:00:00 1.Rxg8+ Kxg8 2.Kg1 Kf7 +- (5.59) Depth: 3/5 00:00:00 1.Rxg8+ Kxg8 2.Kg1 Kf7 3.Kf1 +- (5.59) Depth: 4/6 00:00:00 1.Rxg8+ Kxg8 2.Kg1 b5 3.Kf1 b4 +- (5.53) Depth: 5/7 00:00:00 1.Rxg8+ Kxg8 2.Kg1 b5 3.Kf1 b4 4.Ke2 +- (5.69) Depth: 6/9 00:00:00 1kN 1.Rxg8+-- +- (5.38) Depth: 7/11 00:00:00 5kN 1.Rxg8+-- Kxg8 2.Kg1 b5 3.Kf1 b4 4.Ke2 b3 +- (4.41) Depth: 7/11 00:00:00 6kN 1.Rxg8+-- +- (4.09) Depth: 8/11 00:00:00 12kN 1.Rxg8+-- Kxg8 2.Kg1 b5 3.Kf1 b4 4.Ke2 b3 5.axb3 +- (3.09) Depth: 8/12 00:00:00 13kN 1.Rxg8+ Kxg8 2.Kg1 b5 3.Kf1 b4 4.Ke2 b3 5.axb3 a3 +- (2.91) Depth: 9/12 00:00:00 29kN 1.Rxg8+ Kxg8 2.Kg1 b5 3.Kf1 b4 4.Ke2 b3 5.axb3 a3 6.Kd3 +- (2.88) Depth: 10/13 00:00:00 75kN 1.Rxg8+-- +- (2.56) Depth: 11/14 00:00:00 176kN 1.Rxg8+-- +- (2.56) Depth: 11/16 00:00:00 178kN 1.Rxg8+-- +- (2.25) Depth: 12/15 00:00:00 533kN 1.Rxg8+-- Kxg8 2.g4 b5 3.a3 b4 4.axb4 a3 5.Kg2 a2 6.h4 a1Q -+ (-3.44) Depth: 12/20 00:00:01 573kN 1.Rh3+! -+ (-3.41) Depth: 12/20 00:00:01 614kN 1.Rh3+! Kg7 2.g4 b5 3.Kg2 b4 4.Re3 Rb8 5.Re7+ Kf6 6.Ra7 Rg8 +- (2.06) Depth: 12/25 00:00:16 8180kN 1.Ra3 b5 2.h4 Rf8 3.Kg1 Rf4 4.g3 Rg4 5.Kg2 +- (2.16) Depth: 12/25 00:00:16 9188kN 1.Ra3 b5 2.h4 Rf8 3.Kg1 Rf4 4.g3 Rg4 5.Kg2 +- (2.16) Depth: 12/25 00:00:16 9188kN 1.Ra3 b5 2.Kg1 Ra8 3.Kf1 b4 4.Rd3 Rb8 5.Rd4 a3 6.Rd3 Kg7 +- (2.09) Depth: 13/25 00:00:21 13276kN, tb=1 (Blass, Tel-aviv 18.09.2001) Note that Crafty also has not the knowledge of pawn majority and need a small search to avoid Rxg8+ New position 6rk/1p6/8/8/p7/6R1/P4PPP/7K w - - 0 1 Analysis by Crafty 18.10: 1.Re3 +- (2.47) Depth: 1/4 00:00:00 1.Rxg8+ +- (2.87) Depth: 1/4 00:00:00 1.Rxg8+ Kxg8 2.a3 +- (2.92) Depth: 1/4 00:00:00 1.Rxg8+ Kxg8 2.a3 Kf7 +- (2.62) Depth: 2/4 00:00:00 1.Rxg8+ Kxg8 2.a3 Kf7 +- (3.02) Depth: 3/7 00:00:00 1.Rxg8+ Kxg8 2.a3 Kf7 3.h4 +- (3.02) Depth: 3/7 00:00:00 1.Rxg8+ Kxg8 2.a3 Kf7 3.h4 Ke6 +- (2.82) Depth: 4/9 00:00:00 1.Rxg8+ Kxg8 2.a3 Kf7 3.h4 Ke6 +- (3.22) Depth: 5/10 00:00:00 1.Rxg8+ Kxg8 2.h4 Kf7 3.g4 Ke6 4.a3 +- (3.24) Depth: 5/10 00:00:00 1.Rxg8+ Kxg8 2.h4 b5 3.g4 b4 4.f4 Kf7 +- (3.12) Depth: 6/12 00:00:00 7kN 1.Rxg8+ Kxg8 2.Kg1 b5 3.Kf1 Kf7 4.Ke2 Ke6 5.a3 +- (3.10) Depth: 7/14 00:00:00 17kN 1.Rxg8+ Kxg8 2.Kg1 b5 3.Kf1 b4 4.Ke2 b3 5.axb3 a3 µ (-1.25) Depth: 8/16 00:00:00 49kN 1.Rh3+ µ (-0.85) Depth: 8/16 00:00:00 55kN 1.Rh3+ Kg7 2.a3 Rf8 3.Rg3+ Kh6 4.Kg1 Rc8 5.f4 Rc1+ 6.Kf2 Rc2+ 7.Ke3 b6 +- (2.39) Depth: 8/16 00:00:01 308kN 1.Rh3+ Kg7 2.a3 Kf6 3.Rh7 Re8 4.h4 Re2 5.Rxb7 Rxf2 6.g4 +- (2.37) Depth: 9/19 00:00:03 1098kN 1.Ra3 Re8 2.g3 b5 3.Re3 Rxe3 4.fxe3 b4 5.h4 Kg7 +- (2.40) Depth: 9/19 00:00:03 1241kN (Blass, Tel-aviv 18.09.2001) Uri
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