Author: John Merlino
Date: 13:28:07 05/13/03
Go up one level in this thread
On May 13, 2003 at 15:18:22, Martin Giepmans wrote:
>
>From a game Ruffian - SpiderChess
>
>[D]8/7p/p2k4/1p4p1/4K1P1/P6P/8/8 b - - 0 50
>
>
>
>In this position SpiderChess played 50 .. Kc5? (it should have played
>Ke6 Kd4 a5 -+) and thought it was winning.
>
>The game continued:
>51. Kf5 Kc4 52. Kxg5 Kb3 53. Kh6 Kxa3 54. Kxh7 b4 55. h4 b3 56. g5 b2
>57. h5 b1=Q+ 58. g6 Qe4 59. h6 a5 60. Kg7 Qe7+ 61. Kh8 Qf8+ 62. Kh7 Qf5 63.
>Kg7 Kb3 64. h7 Qe5+ 65. Kg8 Qe8+ 66. Kg7 Qe7+ 67. Kg8 Qd8+ 68. Kg7 Qc7+ 69.
>Kg8 Qc8+ 70. Kg7 Qc3+ 71. Kg8 Qc4+ 72. Kg7 Qd4+ 73. Kg8 Qd5+ 74. Kg7 Qb7+
>75. Kg8 Qa8+ 76. Kg7 Qa7+ 77. Kg8 Qb6 78. Kg7 Kc2 79. h8=Q Qd4+ 80. Kg8
>Qd5+ 81. Kh7 Qh5+ 82. Kg7 Qe5+ 83. Kh7 Qh5+ 84. Kg7 Qe5+ 85. Kh7 Qh2+ 86.
>Kg8 Qb8+ 87. Kh7 Qh2+ 88. Kg7 Qc7+ 89. Kh6 Qf4+ 90. Kh7 Qh4+ 91. Kg7 Qe7+
>92. Kh6 Qe3+ 93. Kh7 Qh3+ 94. Kg8 Qb3+ 95. Kf8 Qb8+ 96. Kg7 Qb7+ 97. Kh6
>Qh1+ 98. Kg7 Qb7+ 99. Kh6 Qh1+ 100. Kg7 Qb7+ 101. Kh6 Qh1+ 102. Kg7 Qb7+
>{Drawn by repetition} 1/2-1/2.
>
>How do other engines fare?
>
>Martin
Chessmaster 9000 finds nothing wrong with 50...Kc5:
Time Depth Score Positions Moves
0:00 4/8 -2.69 6235 50...a5 51.Kd4 h6 52.Kc3 Ke5 53.Kd2
Kd4 54.Ke2
0:00 5/9 -2.64 12849 50...a5 51.Kd4 h6 52.Kc3 Kd5 53.Kc2
b4 54.axb4 axb4 55.Kb3
0:00 6/10 -2.65 24484 50...a5 51.Kd4 h6 52.Ke4 Kc5 53.Kd3
b4 54.axb4+ axb4 55.Kc2 Kc4
0:00 6/10 -2.80 41681 50...Kc5 51.Kd3 a5 52.Kc3 a4 53.Kd3
b4 54.axb4+ Kxb4 55.Kd4 a3
0:00 7/11 -2.87 53163 50...Kc5 51.Kd3 a5 52.Kc3 b4+ 53.axb4+
axb4+ 54.Kb3 Kb5 55.Kb2 Kc4 56.Kc2
b3+ 57.Kb2 h6
0:00 8/12 -3.26 74726 50...Kc5 51.Kd3 a5 52.Kc3 b4+ 53.axb4+
axb4+ 54.Kb3 Kb5 55.Kb2 Kc4 56.Kc2
b3+ 57.Kb2 h6 58.Kc1 Kd4
0:00 9/13 -3.17 120989 50...Kc5 51.Kd3 a5 52.Kc3 b4+ 53.axb4+
axb4+ 54.Kb3 Kb5 55.Kb2 Kc4 56.Kc2
b3+ 57.Kb2 h6 58.Kc1 Kc3
0:01 10/14 -3.36 182816 50...Kc5 51.Kd3 a5 52.Kc3 b4+ 53.axb4+
axb4+ 54.Kb3 Kb5 55.Kb2 Kc4 56.Kc2
b3+ 57.Kb2 h6 58.Kb1 Kc3 59.Kc1
b2+ 60.Kb1
0:01 11/15 -3.29 317502 50...Kc5 51.Kd3 a5 52.Kc3 b4+ 53.axb4+
axb4+ 54.Kb3 Kb5 55.Kb2 Kc4 56.Kc2
b3+ 57.Kb2 Kb4 58.Ka1 Kc3 59.Kb1 b2
0:02 12/16 -3.78 514692 50...Kc5 51.Kd3 a5 52.Kc3 Kd5 53.Kd3
Ke5 54.Ke3 a4 55.Kd2 Kf4 56.Kd3
Kg3 57.Ke4 Kxh3 58.Kf5 b4
0:04 13/17 -3.78 804669 50...Kc5 51.Kd3 a5 52.Kc3 Kd5 53.Kd3
Ke5 54.Ke3 a4 55.Kd2 Kf4 56.Kd3
Kg3 57.Ke4 Kxh3 58.Kf5 b4
0:10 14/18 -4.75 1578501 50...Kc5 51.Kd3 a5 52.Kc3 Kd5 53.a4
b4+ 54.Kd3 h6 55.Kc2 Kc4 56.Kb2
b3 57.Kc1 Kb4 58.Kb1 Kxa4 59.Kb2
Kb4
0:23 15/19 -4.97 3134673 50...Kc5 51.Kd3 a5 52.Kc3 Kd5 53.Kd3
Ke5 54.Ke3 a4 55.Kd2 Kf4 56.Kd3
Kg3 57.Ke4 Kxh3 58.Kf5 b4 59.axb4
a3 60.Kxg5
5:21 16/20 -7.34 41907384 50...Kc5 51.Kf5 a5 52.Kxg5 b4 53.axb4+
axb4 54.Kh6 b3 55.Kxh7 b2 56.g5
b1=Q+ 57.Kh6 Qh1 58.g6 Qxh3+ 59.Kg7
Kd6 60.Kg8 Ke7 61.Kg7 Qc8 62.Kh7
Qf8
It appears that 51...Kc4 (using the king to capture the pawn) instead of 51...a5
(to trade off pawns) was the error.
After 50...Kc5 51.Kf5 a5! 52.Kxg5 b4 53.axb4+ axb4 54.Kh6 b3 55.Kxh7, Black has
a tablebase Mate in 10 with EITHER 55...b2 or 55...Kd5.
The only other option for White (after 50...Kc5) that I can find is 51.Kd3,
which also appears to lose after 51...a5. White can respond with 52.Kc3, but
after 52...a4! White is in zugzwang. White's only other option is 52.Ke4 which
is met by 52...b4, trading off pawns to a won game for Black.
jm
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