Author: Bruce Moreland
Date: 14:18:22 12/17/00
Go up one level in this thread
If the 50th move by either side is a mate, the game is not drawn. Programs need
to handle this correctly, and it is a little tricky.
Mine sees mate in 4 at the position preceding black's 152nd move.
I think I could still have bugs in very rare cases, perhaps when two pieces
check at once.
bruce
On December 17, 2000 at 11:14:13, Dieter Buerssner wrote:
>I think, the following game is interesting for interpreting the 50 moves
>rule. If I am interpreting correctly, Yace could have won, by mating Crafty
>in the last possible move, before Crafty could claim a draw. I think there
>is a subtle bug in my engine, and it seems in other engines as well.
>In search, after I made a move, I check if the move is legal. Then, when
>a 3-fold repetition is found, or a draw due to 50 moves rule, I give the
>move draw score. This seems to work well for for the repetition case,
>but I forgot about a very important case concerning the 50 moves rule.
>When the last possible move is a mating move, it should obviously be
>a win. I hope this interpretation of the rules is correct. Perhaps
>somebody can confirm this?
>
>How does your engine handle this situation?
>
>If I have tested correcly, Little Goliath and Crafty both don't see the win.
>Fritz 6a sees the win.
>
>I guess, after I fix this problem, it will never ever happen again in a game ...
>
>[Event "Computer chess game 0 240 +2 0 0"]
>[Site "?"]
>[Date "2000.12.17"]
>[Round "6"]
>[White "Crafty 17.13"]
>[Black "Yace 0.23.33"]
>[Result "1/2-1/2"]
>[WhiteElo "0"]
>[BlackElo "0"]
>[Timecontrol "0 240 +2 0 0"]
>[Time "Sun Dec 17 05:43:08 2000"]
>[last_book_pos "r3kb1r/p2qnppp/1pn1p3/1bppP3/3P4/PBP2N2/1P2NPPP/R1BQR1K1 b kq -
>2 13"]
>[last_book_move "13...Bxe2"]
>[LogFile "logs\yace0006.log"]
>
>1. e4 e6 2. d4 d5 3. Nc3 Bb4
>4. e5 b6 5. a3 Bf8 6. Bb5+ c6
>7. Ba4 Ba6 8. Nce2 Bb5 9. Bb3 c5
>10. c3 Nc6 11. Nf3 Qd7 {-0.26} 12. O-O Nge7
>13. Re1 Bxe2 14. Qxe2 c4 {-0.50} 15. Ba4 h5 {-0.50}
>16. b3 cxb3 {-0.65} 17. Bxb3 O-O-O {-0.47} 18. Ng5 Qe8 {-0.54}
>19. Rb1 Kb8 {-0.51} 20. Qa6 Rc8 {-0.50} 21. Ba4 Nf5 {-0.45}
>22. Bb5 Be7 {-0.41} 23. Qa4 Rf8 {-0.43} 24. Bf4 Ka8 {-0.45}
>25. Rb2 Rc7 {-0.45} 26. Reb1 Qc8 {-0.51} 27. Ba6 Qd8 {-0.33}
>28. Nf3 g5 {-0.39} 29. Bc1 g4 {-0.20} 30. Ne1 Na5 {-0.20}
>31. Rc2 Qe8 {-0.09} 32. Bb5 Qc8 {0.12} 33. Bb2 f6 {0.17}
>34. exf6 Bxf6 {0.12} 35. Re2 Nd6 {0.13} 36. Bd3 Nac4 {0.12}
>37. Bc1 e5 {0.10} 38. dxe5 Bxe5 {0.15} 39. Qd1 Rc5 {0.22}
>40. Bxc4 dxc4 {0.27} 41. a4 Qc6 {0.34} 42. Qc2 Rd5 {0.41}
>43. Ba3 Rd8 {0.40} 44. Rd2 Rxd2 {1.00} 45. Qxd2 Qc7 {0.82}
>46. Qe3 Qh7 {0.38} 47. Bxd6 Bxd6 {0.51} 48. Qg5 Be7 {0.63}
>49. Qc1 Bc5 {0.69} 50. Rb2 Rf8 {0.67} 51. Re2 Qd7 {0.69}
>52. Qg5 Qf7 {0.63} 53. Qd2 Qf5 {0.56} 54. Nc2 Qd3 {0.57}
>55. Qe1 Qd7 {0.97} 56. Rd2 Qe8 {0.53} 57. Qxe8+ Rxe8 {0.44}
>58. Kf1 a6 {0.41} 59. Rd7 Kb8 {0.37} 60. f4 gxf3 {0.41}
>61. gxf3 Rf8 {0.44} 62. Ne1 Kc8 {0.48} 63. Rd5 h4 {0.45}
>64. Rh5 Be7 {0.51} 65. Ke2 Bf6 {0.59} 66. Nc2 Re8+ {0.49}
>67. Ne3 Bxc3 {0.58} 68. Rxh4 b5 {0.59} 69. Re4 Rxe4 {0.50}
>70. fxe4 Bb2 {0.48} 71. axb5 axb5 {0.33} 72. h4 Kd7 {0.39}
>73. h5 Ke6 {0.48} 74. h6 Kf6 {0.77} 75. Nf5 Kg6 {0.24}
>76. Nd6 c3 {0.15} 77. Kd3 b4 {0.04} 78. e5 Kxh6 {0.04}
>79. e6 b3 {0.04} 80. e7 c2 {0.03} 81. e8=Q c1=Q {0.03}
>82. Qf8+ Kh5 {0.00} 83. Qf7+ Kh4 {0.00} 84. Qxb3 Qf1+ {0.00}
>85. Ke4 Qe1+ {0.00} 86. Kd5 Qe5+ {0.00} 87. Kc6 Bc3 {0.00}
>88. Nc4 Qe6+ {0.06} 89. Kc7 Be5+ {0.06} 90. Kd8 Qd5+ {0.06}
>91. Ke8 Qc6+ {0.06} 92. Ke7 Bf6+ {0.06} 93. Kf7 Bd4 {0.07}
>94. Qb4 Kh5 {0.08} 95. Nd6 Qd7+ {0.08} 96. Kf8 Bg7+ {0.91}
>97. Kg8 Be5 {0.91} 98. Nf7 Qc8+ {0.91} 99. Kh7 Qf5+ {0.90}
>100. Kg8 Qc8+ {0.90} 101. Kh7 Qc2+ {0.90} 102. Kg8 Qg6+ {0.90}
>103. Kf8 Bg7+ {0.90} 104. Ke7 Qf6+ {0.91} 105. Kd7 Qxf7+ {0.91}
>106. Kc6 Qe8+ {0.92} 107. Kb6 Qb8+ {0.92} 108. Ka5 Qa8+ {0.92}
>109. Kb6 Qd5 {0.93} 110. Qb5 Bd4+ {0.92} 111. Ka5 Bc5 {0.92}
>112. Qc4 Qd8+ {0.92} 113. Kb5 Qb6+ {0.92} 114. Ka4 Qd6 {0.91}
>115. Kb5 Qb6+ {0.91} 116. Ka4 Qc6+ {0.91} 117. Ka5 Bb6+ {0.91}
>118. Kb4 Qd6+ {0.91} 119. Kb5 Bd4 {0.91} 120. Qc6 Qe5+ {0.91}
>121. Kc4 Qf4 {0.91} 122. Qd5+ Be5+ {0.91} 123. Kb5 Qf5 {0.91}
>124. Kc4 Kg5 {0.91} 125. Qd8+ Kh6 {0.91} 126. Qd3 Qc8+ {0.93}
>127. Kb5 Qb7+ {0.91} 128. Kc5 Qb8 {0.91} 129. Kc4 Qb6 {0.91}
>130. Qd5 Qa6+ {0.91} 131. Kc5 Qa5+ {0.91} 132. Kc4 Qc3+ {0.91}
>133. Kb5 Qe3 {0.91} 134. Qg8 Qe4 {0.91} 135. Qg1 Qd3+ {0.92}
>136. Kb4 Bd6+ {0.92} 137. Ka5 Qc4 {0.92} 138. Kb6 Bc7+ {0.92}
>139. Kb7 Bf4 {0.92} 140. Kb6 Qb4+ {0.93} 141. Kc6 Qe4+ {0.93}
>142. Kb5 Qd3+ {0.93} 143. Kc6 Qf3+ {0.93} 144. Kb5 Qe2+ {0.93}
>145. Kc6 Qf3+ {0.92} 146. Kb5 Qd3+ {0.92} 147. Kc6 Qe4+ {0.92}
>148. Kb5 Qe2+ {0.92} 149. Kb4 Bd2+ {0.93} 150. Kb3 Qd3+ {17.87}
>151. Ka2 Qc4+ {Mat11} 152. Ka1 Qc3+ {0.00} 153. Ka2 Kh5 {0.00}
>154. Qh2+ Kg6 {0.00} 155. Qg1+ Bg5 {0.00} 1/2-1/2 {Draw}
>
>I think, the forced win is
>
>152...Bc3+ 153. Kb1 Qb3+ 154. Kc1 Qb2+ 155. Kd1 Qd2#
>
>Regards,
>Dieter
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