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Subject: Re: game position: Cerbro vs Horizon

Author: Ron Murawski

Date: 07:35:29 07/14/02

Go up one level in this thread


On July 14, 2002 at 02:57:42, Gerd Isenberg wrote:

>On July 14, 2002 at 02:14:33, Ron Murawski wrote:
>
>>Horizon 3.2 drew a game against Cerebro 1.10 in Leo Dijksman's 3rd Division
>>Ridderkerk tournament. Just for the record, here is the game:
>>
>>[Event "WBEC3_3rdDivision"]
>>[Site "DUAL-P3-933"]
>>[Date "2002.07.12"]
>>[Round "1.3"]
>>[Number "399"]
>>[White "Cerebro 1.10b"]
>>[Black "Horizon 3.2"]
>>[Result "1/2-1/2"]
>>[TimeControl "40/2400"]
>>
>>1. d4 d5 2. c4 c6 3. Nc3 dxc4 4. e3 b5 5. a4 b4 6. Ne4 Nf6 7. Nxf6+ exf6 8.
>>Bxc4 Be7 9. Qc2 Be6 10. Ne2 Bxc4 11. Qxc4 O-O 12. O-O Qd5 13. Qc2 c5 14. e4
>>Qb7 15. d5 f5 16. f3 Nd7 17. Bf4 fxe4 18. fxe4 Bf6 19. g4 h6 20. Kh1 b3 21.
>>Qc1 Rfe8 22. Ng3 c4 23. Bd2 Be5 24. Bf4 Bf6 25. Qxc4 Bxb2 26. Rad1 Rac8 27.
>>Qe2 Rc2 28. Rd2 Rxd2 29. Qxd2 Bf6 30. Be3 Be5 31. Bf4 Bxf4 32. Qxf4 Nf6 33.
>>Qf3 b2 34. Rb1 Rc8 35. Ne2 Rc4 36. g5 Nxe4 37. gxh6 Rxa4 38. hxg7 Nd2 39.
>>Qh5 Rh4 40. Rxb2 Qxb2 41. Qxh4 Qb1+ 42. Ng1 Qe4+ 43. Qxe4 Nxe4 44. Ne2 Kxg7
>>45. Kg2 Kf6 46. h4 Ke5 47. h5 Nf6 48. h6 Kxd5 49. Kf1 Ke4 50. Ke1 Nh7 51.
>>Kd2 Kf5 52. Kc3 Kg6 53. Kb4 Kh5 54. Nd4 Kg4 55. Ka5 Kf4 56. Ka6 Ke4 57. Ne2
>>Ke3 58. Ng3 Kf4 59. Ne2+ Kf3 60. Nd4+ Kf2 61. Nf5 Kf3 62. Nd6 Kf4 63. Nxf7
>>Kf5 64. Kxa7 Ke6 65. Ka6 Kxf7 66. Ka5 Ke8 67. Ka4 Kd8 68. Ka3 Kc8 69. Ka2
>>Kb8 70. Ka1 Ka8 71. Kb1 Kb8 72. Ka1 Ka8 73. Kb1 Kb8 74. Ka1
>>{Three fold repetition} 1/2-1/2
>>
>>
>>I believe that Horizon had a win in hand until this position:
>>
>>[D] 6k1/pq3pP1/8/3P4/r3n3/5Q2/1p2N2P/1R5K b - - 0 38
>>
>>where Horizon played 38...Nd2 with an eval score of more that +6.00.
>>
>>Here's two WinBoard analysis snapshots after 5 minutes running on an AMD 1.8 GHz
>>w/64 MB hash for Horizon and for Crafty.
>>
>>Horizon 3.2 (where +6.70 means Black is ahead)
>>depth=11 15/35 +6.70 Nd2 Qh5 Rh4 Rxb2 Qxb2 Qxh4 Qb1+ Ng1 Qxg1+ Kxg1 Nf3+ Kf2
>>Nodes: 77677043 NPS: 258071
>>Time: 00:05:00.99
>>
>>Crafty 18.15 (where -5.41 means Black is ahead)
>>depth=14 1/35 -5.41 1. ... Nd2 2. Qf5 Rh4 3. Rd1 b1=Q 4. Rxb1 Qxb1+ 5. Qxb1 Nxb1
>>6. d6 Rh6 7. d7 Rd6 8. Ng3 Nd2 9. h4 Kxg7
>>Nodes: 319129163 NPS: 1060758
>>Time: 00:05:00.85
>>
>>It is interesting to note that Crafty 18.15 endorses Horizon's move 38...Nd2 and
>>also scores it as Black ahead big-time.
>>
>>But when I analyzed using Chess Tiger and Fritz, I saw a different assessment.
>>(In both of the following analyses, the more negative the score the better it is
>>for Black.)
>>
>>Here's analysis by Chess Tiger 14.0:
>>
>>1...Qxd5 2.Rxb2 Kxg7 3.Qg2+ Kf8 4.Rb8+ Ke7 5.Rb1 Rc4
>>  ³  (-0.50)   Depth: 7   00:00:00  237kN
>>1...Rb4 2.Nf4 Qb5 3.Qg2 Qc4 4.Nh5 Qxd5
>>  ³  (-0.64)   Depth: 7   00:00:00  313kN
>>1...Rb4 2.Nf4 Qe7 3.Nd3 Nd2 4.d6 Qxd6 5.Qa8+ Rb8
>>  ³  (-0.62)   Depth: 8   00:00:01  650kN
>>1...Rb4 2.Qh5 Kxg7 3.Nd4 Nf2+ 4.Kg2 Nd3 5.Qg5+ Kf8 6.Qd8+ Kg7 7.Qg5+
>>  =  (0.15)   Depth: 9   00:00:01  1130kN
>>1...Qxd5 2.Rxb2 Kxg7 3.Qg4+ Ng5+ 4.Qg2 Qd1+ 5.Qg1 Qxg1+ 6.Kxg1 Rg4+ 7.Ng3 a5
>>8.Rb7 a4
>>  µ  (-0.72)   Depth: 9   00:00:02  1559kN
>>1...Nd2 2.Qh5 Rh4 3.Rxb2 Qxb2 4.Qxh4 Qb1+ 5.Ng1 Qxg1+ 6.Kxg1 Nf3+ 7.Kh1 Nxh4
>>  µ  (-0.86)   Depth: 9   00:00:02  1670kN
>>1...Nd2 2.Qh5 Rh4 3.Rxb2 Qxb2 4.Qxh4 Qb1+ 5.Ng1 Qxg1+ 6.Kxg1 Nf3+ 7.Kh1 Nxh4
>>  µ  (-0.86)   Depth: 10   00:00:03  1828kN
>>1...Ng5 2.Qf5 Ra1 3.Nc3 Rxb1+ 4.Nxb1 Ne6 5.h4 Nxg7 6.Qe5 a5
>>  µ  (-1.10)   Depth: 10   00:00:03  2386kN
>>1...Ng5 2.Qf5 Ra1 3.Nc3 Qb4 4.Qe5 Rxb1+ 5.Nxb1 Qe4+ 6.Qxe4 Nxe4
>>  -+  (-1.44)   Depth: 11   00:00:05  3169kN
>>1...Qxd5
>>  -+  (-2.00)   Depth: 11   00:00:10  6698kN
>>1...Qxd5 2.Rxb2 Ng3+ 3.Kg2 Nxe2 4.Qxd5 Nf4+ 5.Kg3 Nxd5 6.Rd2 Nf4
>>  -+  (-2.56)   Depth: 11   00:00:12  7886kN
>>1...Qxd5 2.Rxb2 Ng3+ 3.Kg2 Nxe2 4.Qxd5 Nf4+ 5.Kf3 Nxd5 6.Rg2 Rh4 7.Kf2 a5
>>  -+  (-3.12)   Depth: 12   00:00:30  19934kN
>>1...Qxd5 2.Rxb2
>>  -+  (-3.12)   Depth: 13   00:00:32  21494kN
>>1...Qxd5 2.Rxb2 Ng3+ 3.Kg2 Nxe2 4.Qxd5 Nf4+ 5.Kf1 Nxd5 6.Rb5 Rd4 7.Rb7 Kxg7
>>8.Rxa7 Rd2
>>  -+  (-3.76)   Depth: 14   00:01:12  48458kN
>>1...Qxd5 2.Rxb2 Ng3+ 3.Kg2 Nxe2 4.Qxd5 Nf4+ 5.Kf3 Nxd5 6.Rg2 Rf4+ 7.Ke2 Rh4
>>8.Kf3 a5 9.Rg5 Nf4
>>  -+  (-3.42)   Depth: 15   00:02:07  85404kN
>>1...Qxd5 2.Rxb2 Ng3+ 3.Kg2 Nxe2 4.Qxd5 Nf4+ 5.Kf1 Nxd5 6.Rb5 Nf6 7.Rb7 Rf4+
>>8.Ke1 Kxg7 9.Rxa7 Rh4
>>  -+  (-3.92)   Depth: 16   00:07:17  299312kN, tb=27
>>1...Ng5 2.Qf5 Ra1 3.Nc3 Qb4 4.Qc8+ Kxg7 5.Qf5 f6 6.Qc2 Qxc3 7.Qxc3 Rxb1+ 8.Kg2
>>Rg1+ 9.Kxg1 b1Q+ 10.Kg2
>>  -+  (-4.14)   Depth: 16   00:20:12  841933kN, tb=32
>>1...Ng5 2.Qf5 Ra1 3.Nc3 Qb4 4.Qc8+ Kxg7 5.Qf5 f6 6.Qd3 Qb3 7.Qg3 Rxb1+ 8.Nxb1
>>Qxd5+ 9.Qg2 Qd3 10.Nd2
>>  -+  (-4.26)   Depth: 17   00:32:43  1364414kN, tb=45
>>
>>Here's analysis by Fritz 6 Light:
>>
>>1...Kxg7!
>>  ³  (-0.44)   Depth: 1/8   00:00:00
>>1...Kxg7! 2.Rg1+ Kh8
>>  ³  (-0.63)   Depth: 1/8   00:00:00
>>1...Kxg7 2.Rg1+ Kf8
>>  ³  (-0.44)   Depth: 2/5   00:00:00
>>1...Rb4!
>>  ³  (-0.56)   Depth: 2/6   00:00:00
>>1...Rb4! 2.Ng3 Nxg3+ 3.Qxg3 Qxd5+ 4.Kg1
>>  µ  (-0.97)   Depth: 2/8   00:00:00
>>1...Nd2!
>>  µ  (-1.03)   Depth: 2/9   00:00:00
>>1...Nd2! 2.Qf5 Nxb1 3.Qxb1 Qxd5+ 4.Kg1 Kxg7 5.Qxb2+ f6
>>  -+  (-2.50)   Depth: 2/11   00:00:00
>>1...Nd2--
>>  ³  (-0.53)   Depth: 3/7   00:00:00
>>1...Nd2-- 2.Qh5 Rh4
>>  ±  (0.72)   Depth: 3/12   00:00:00  1kN
>>1...Rb4!
>>  ²  (0.56)   Depth: 3/15   00:00:00  1kN
>>1...Rb4! 2.Qh5
>>  µ  (-0.94)   Depth: 3/15   00:00:00  2kN
>>1...Rb4--
>>  ³  (-0.59)   Depth: 4/12   00:00:00  2kN
>>1...Rb4--
>>  ³  (-0.59)   Depth: 4/12   00:00:00  3kN
>>1...Qxd5!
>>  ³  (-0.63)   Depth: 4/13   00:00:00  8kN
>>1...Qxd5! 2.Rxb2 Ng3+ 3.Kg2 Qxf3+ 4.Kxf3 Nxe2 5.Rxe2 Kxg7
>>  µ  (-0.94)   Depth: 4/15   00:00:00  12kN
>>1...Qxd5 2.Rxb2 Ng3+ 3.Kg2 Qxf3+ 4.Kxf3 Nxe2 5.Rxe2 Kxg7
>>  µ  (-0.94)   Depth: 5/16   00:00:00  26kN
>>1...Qxd5 2.Rxb2 Ng3+ 3.Kg2 Qxf3+ 4.Kxf3 Ne4 5.Ng3 Nxg3 6.hxg3
>>  µ  (-1.16)   Depth: 6/18   00:00:00  55kN
>>1...Qxd5 2.Rxb2 Nf2+ 3.Kg2 Qxf3+ 4.Kxf3 Nd3 5.Rb8+ Kxg7 6.Ng3
>>  µ  (-1.09)   Depth: 7/20   00:00:00  182kN
>>1...Qxd5!
>>  -+  (-1.41)   Depth: 8/22   00:00:00  462kN
>>1...Qxd5! 2.Rxb2 Ng3+ 3.Kg2 Nxe2 4.Qxd5 Nf4+ 5.Kf3
>>  -+  (-2.84)   Depth: 8/23   00:00:00  1048kN
>>1...Qxd5 2.Rxb2 Ng3+ 3.Kg2 Nxe2 4.Qxd5 Nf4+ 5.Kf3 Nxd5 6.Rd2
>>  -+  (-3.06)   Depth: 9/25   00:00:01  1725kN
>>1...Qxd5 2.Rxb2 Ng3+ 3.Kg2 Nxe2 4.Qxd5 Nf4+ 5.Kf3 Nxd5 6.Rg2
>>  -+  (-3.13)   Depth: 10/27   00:00:01  2892kN
>>1...Qxd5 2.Rxb2 Ng3+ 3.Kg2 Nxe2 4.Qxd5 Nf4+ 5.Kf3 Nxd5 6.Rg2
>>  -+  (-3.34)   Depth: 11/28   00:00:03  7062kN
>>1...Qxd5!
>>  -+  (-3.66)   Depth: 12/32   00:00:10  19591kN
>>1...Qxd5! 2.Rxb2 Ng3+ 3.Kg2 Nxe2 4.Qxd5 Nf4+ 5.Kf3 Nxd5 6.Rd2
>>  -+  (-4.25)   Depth: 12/32   00:00:34  70353kN
>>1...Qxd5 2.Rxb2 Ng3+ 3.Kg2 Nxe2 4.Qxd5 Nf4+ 5.Kf3 Nxd5 6.Rd2
>>  -+  (-4.47)   Depth: 13/36   00:01:08  138628kN, tb=3
>>1...Qxd5 2.Rxb2 Ng3+ 3.Kg2 Nxe2 4.Qxd5 Nf4+ 5.Kf3 Nxd5 6.Rd2
>>  -+  (-4.53)   Depth: 14/37   00:06:02  779323kN, tb=90
>>
>>So it seems that 38...Qxd5 or 38...Ng5 can win the game for Black. If you force
>>Horizon's game move 38...Nd2 into either Tiger or Fritz the eval scoring gets
>>close to 0.00.
>>
>>If anyone has a clue why Horizon and Crafty's eval scoring are off by more than
>>5 pawns for this position I would be interested. All theories are welcome.
>>
>>Ron
>
>IsiChess has also score close to draw after 38...Nd2 with 39.Qh5 Rh4 40.Rxb2
>Qxb2 41.Qxh4 Qb1 42.Ng1 Qe4 43.Qxe4 Nxe4. If king danger is detected by eval,
>nullmove is disabled.
>
>Gerd

Thanks for this idea. I guess the current null-move is too dumb. I will try to
implement your idea and test. Right now the search and eval are cleanly
separated.

Ron



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