Elixir v1.0 draws highly won endgame #56
Description
In my recent #55 i indicated Elixir v1.0 needs a certain improvement in the opening phase of the game. Now i discovered it needs a certain improvement in the endgame as well.
The opening phase needs a totally different approach then the endgame, while the latter means few pieces are left on the board and pawns get more important because of their ability to promote. The #55 example game was a battle with Black against KnightX v4.0. Here's a 7m3s game with White against the same engine. Elixir v1.0 should clearly have won, but it made a terrible decision in the endgame which is hard to understand. However, on closer inspection Elixir v1.0 is highly capable of avoiding the blunder it made.
Here's the concerning position, Elixir v1.0 was going to make its 55th move :
8/1B4kp/6p1/8/p1r5/4K3/1P2R2P/8 w - - 1 55
In the game the engine played 55.Be4 after 3.4 seconds, but it's a blunder. I discovered this by the LiChess game analysis tool, using the newest Stockfish. At first it's not clear why Be4 is wrong; it's about the fact few pawns are left on the board, esp. the h-pawn, which can eventually promote on a black square, being the opposite color of the remaining Bishop. In practical play this means it's hard to support this pawn to the last row, esp. because it's an edge-pawn. A player should be aware of this when exchanging pieces : despite the fact you're ahead in material tremendously, the opponent might still be able to draw.
At first i assumed this blunder was caused by the horizon-effect : promoting the h-pawn is too many plies ahead. But i proved Elixir v1.0 is actually capable of avoiding the blunder : after the game i let the engine analyse the position and within 1 second it rejected Be4 .. see the above screenshot.
Is this caused by the Hash / TT not being managed properly ? My gut feeling says so ..
I hope you can discover why Elixer v1.0 made that blunder. Solving this bug (?) will greatly improve its strength !
[Event "engine vs engine"]
[Site "Holland"]
[Date "2024.06.11"]
[Round "?"]
[White "Elixir v1.0"]
[Black "KnightX v4.0"]
[Result "1/2-1/2"]
[ECO "C42"]
[GameDuration "00:30:18"]
[Opening "Petrov"]
[PlyCount "353"]
[TimeControl "420+3"]
[Variation "Classical attack"]
1. e4 {+0.15/26 25s} e5 {-0.30/20 17s} 2. Nf3 {+0.29/27 25s} Nf6 {-0.22/20 17s}
3. Nxe5 {+0.20/26 22s} d6 {-0.30/22 16s} 4. Nf3 {+0.31/26 16s}
Nxe4 {-0.25/22 16s} 5. d4 {+0.29/26 20s} Be7 {-0.22/21 15s}
6. Bd3 {+0.29/26 26s} d5 {-0.30/21 15s} 7. O-O {+0.38/25 30s} Bf5 {-0.30/21 15s}
8. Nc3 {+0.41/26 15s} O-O {-0.32/21 14s} 9. Re1 {+0.50/25 14s}
Bb4 {-0.37/22 14s} 10. Nxe4 {+0.57/26 16s} Bxe1 {-0.32/24 13s}
11. Neg5 {+0.73/26 16s} Bxf2+ {-0.42/24 13s} 12. Kxf2 {0.00/25 35s}
Qf6 {-0.37/24 13s} 13. Nh3 {+0.72/24 16s} Bxh3 {-0.10/18 14s}
14. gxh3 {+0.95/23 12s} Nd7 {-0.15/18 13s} 15. c3 {+0.74/23 22s}
Qd6 {-0.30/19 12s} 16. Qc2 {+0.97/21 21s} Nf6 {-0.55/18 11s}
17. Ne5 {+0.68/21 15s} c5 {-0.57/17 11s} 18. Kg2 {+0.86/21 8.3s}
cxd4 {-0.45/18 11s} 19. cxd4 {+0.80/24 7.0s} Qb6 {-0.55/20 11s}
20. Be3 {+0.84/24 7.1s} Rac8 {-0.60/21 10s} 21. Qb3 {+0.78/24 9.8s}
Qxb3 {-0.82/23 10s} 22. axb3 {+0.77/25 8.0s} a6 {-1.22/25 14s}
23. Bf4 {+0.79/23 13s} Rfe8 {-0.72/24 9.6s} 24. b4 {+0.75/23 7.3s}
g6 {-0.65/17 9.3s} 25. Rf1 {+0.79/23 7.9s} Nh5 {-1.15/21 8.9s}
26. Bh6 {+0.81/22 8.7s} f6 {-0.72/22 18s} 27. Nd7 {+0.88/23 4.9s}
f5 {-0.82/20 8.3s} 28. Nc5 {+0.86/22 4.8s} Rc7 {-0.90/20 8.1s}
29. Na4 {+0.74/19 4.9s} Re6 {-0.77/17 8.0s} 30. Bd2 {+0.66/21 7.6s}
Nf6 {-0.72/20 7.9s} 31. Nc5 {+0.41/19 4.8s} Re8 {-0.65/20 7.7s}
32. Bf4 {+0.82/22 4.2s} Rce7 {-0.62/20 10s} 33. Bd6 {0.00/23 13s}
Rf7 {-0.75/21 7.8s} 34. Be5 {+0.82/21 4.0s} Ne4 {-0.72/18 7.2s}
35. Na4 {+0.78/21 4.4s} Nf6 {-1.20/19 7.1s} 36. Nc3 {+0.91/21 3.7s}
Nd7 {-1.07/19 6.9s} 37. Bf4 {+0.83/22 3.9s} Nf6 {-1.25/20 6.6s}
38. b5 {+0.99/24 3.7s} a5 {-1.75/19 6.6s} 39. Bc2 {+1.44/19 5.7s}
Rd7 {-1.70/17 6.6s} 40. b6 {+1.96/23 3.7s} Re6 {-2.15/18 6.3s}
41. Bc7 {+1.94/23 4.1s} Ne4 {-2.10/20 6.3s} 42. Ba4 {+1.97/26 3.7s}
Rdd6 {-2.25/24 7.1s} 43. Nxe4 {+2.02/27 6.1s} fxe4 {-2.67/26 6.0s}
44. Bxd6 {+2.25/27 4.5s} Rxd6 {-2.50/26 5.8s} 45. Bb3 {+2.34/26 3.5s}
Kg7 {-2.82/23 7.4s} 46. Rf2 {+2.19/27 3.6s} Kh6 {-2.97/24 9.2s}
47. Ba2 {+2.40/25 3.3s} a4 {-2.85/22 6.0s} 48. Kg3 {0.00/27 9.4s}
Kg7 {-3.17/25 5.3s} 49. h4 {+2.77/26 4.8s} e3 {-3.17/23 5.3s}
50. Re2 {+2.76/28 5.1s} Rxb6 {-3.15/22 5.2s} 51. Bxd5 {+2.85/27 2.8s}
Rb4 {-3.22/24 5.0s} 52. Kf3 {+2.92/26 3.5s} Rxd4 {-3.32/23 5.1s}
53. Bxb7 {+2.85/26 2.7s} Rxh4 {-3.42/24 4.9s} 54. Kxe3 {+2.86/26 2.8s}
Rc4 {-3.42/25 4.9s} 55. Be4 {+3.01/21 3.4s} Kf6 {-3.42/20 4.8s}
56. Kd3 {0.00/25 8.0s} Rc5 {-3.42/19 4.7s} 57. Kd4 {+2.99/22 2.2s}
Rc7 {-3.65/19 4.7s} 58. Rc2 {0.00/22 7.4s} Ra7 {-3.52/20 4.7s}
59. Rc3 {+3.42/21 2.2s} Ra5 {-3.65/19 4.5s} 60. Rc6+ {+3.65/22 2.1s}
Kg7 {-4.27/21 5.7s} 61. Rc7+ {+3.71/25 4.6s} Kh6 {-4.42/24 4.4s}
62. Bd5 {+3.85/22 4.3s} a3 {-4.55/24 4.4s} 63. bxa3 {+3.93/24 2.6s}
Rxa3 {-4.55/25 4.4s} 64. Bg8 {0.00/25 6.7s} Ra4+ {-4.55/23 4.3s}
65. Kc5 {+3.93/21 2.5s} Rh4 {-3.94/16 4.3s} 66. Rxh7+ {+6.94/34 2.1s}
Kg5 {-4.55/2 0s} 67. Rxh4 {+12.81/34 2.1s} Kxh4 {-8.60/28 4.3s}
68. Be6 {+14.29/48 4.4s} Kg5 {-8.85/33 4.3s} 69. Kd6 {+16.29/39 2.0s}
Kf4 {-8.85/21 4.3s} 70. Kd5 {+16.22/38 2.3s} Kg5 {-8.85/36 4.2s}
71. Ke5 {+13.31/33 3.1s} Kh5 {-8.85/39 4.1s} 72. Kf6 {+13.31/36 2.0s}
Kh6 {-8.85/43 4.0s} 73. Bb3 {+13.05/19 2.9s} Kh7 {-8.85/45 4.1s}
74. h3 {+13.05/23 2.3s} Kh6 {-8.85/47 4.1s} 75. Bc2 {+13.00/34 2.2s}
Kh7 {-8.85/47 3.9s} 76. Kg5 {+13.00/17 4.1s} Kg7 {-8.85/46 3.9s}
77. Be4 {+13.00/22 2.4s} Kf7 {-8.85/41 3.9s} 78. Bxg6+ {+12.81/26 2.1s}
Kg7 {-8.87/57 3.8s} 79. Be4 {+13.76/48 2.4s} Kf8 {-8.87/31 3.8s}
80. Bd5 {+16.04/35 3.6s} Kg7 {-8.87/49 3.8s} 81. h4 {+16.56/22 2.5s}
Kh7 {-8.87/50 3.8s} 82. h5 {0.00/50 7.0s} Kh8 {-8.87/50 3.7s}
83. h6 {+17.21/19 3.1s} Kh7 {-7.32/2 0s} 84. Kh5 {+17.22/18 2.8s}
Kh8 {-7.37/2 0s} 85. Bf3 {+16.69/24 4.1s} Kh7 {-8.87/52 3.9s}
86. Be4+ {+16.38/38 6.0s} Kh8 {-8.87/43 3.9s} 87. Kg4 {+16.51/13 2.0s}
Kg8 {-8.87/2 0s} 88. Kg5 {+16.56/16 2.4s} Kh8 {-8.87/35 4.0s}
89. Bd3 {+13.02/14 1.9s} Kg8 {-8.87/2 0s} 90. Ba6 {+13.02/21 4.1s}
Kh7 {-8.87/46 4.0s} 91. Bc8 {+12.93/19 3.6s} Kh8 {-8.87/58 4.0s}
92. Bh3 {0.00/44 6.1s} Kg8 {-8.87/52 4.0s} 93. Be6+ {+12.96/14 3.1s}
Kh7 {-9.02/59 1.9s} 94. Bf5+ {+16.21/15 2.9s} Kg8 {-9.02/56 4.0s}
95. Kf6 {+13.05/16 1.9s} Kh8 {-8.97/26 4.0s} 96. Bg6 {+13.42/29 1.8s}
Kg8 {-8.97/2 0s} 97. Kg5 {+13.42/35 4.0s} Kh8 {-8.97/26 4.0s}
98. Kg4 {+14.47/27 2.4s} Kg8 {-8.97/2 0s} 99. Bc2 {+12.93/17 2.1s}
Kh8 {-8.97/28 4.1s} 100. Kf4 {+12.93/22 2.0s} Kg8 {-8.97/2 0s}
101. Ke5 {+13.28/18 1.9s} Kh8 {-8.87/24 4.1s} 102. Kf5 {+12.90/18 2.9s}
Kh7 {-8.87/28 4.2s} 103. Kg5+ {+12.90/19 2.6s} Kh8 {-8.87/30 4.1s}
104. Bb1 {+12.90/35 2.0s} Kg8 {-8.27/2 0s} 105. Kf4 {0.00/16 6.5s}
Kh8 {-8.87/29 4.2s} 106. Kg3 {+11.17/14 3.3s} Kg8 {-8.87/2 0s}
107. Bc2 {+12.37/14 2.1s} Kh8 {-8.87/29 4.2s} 108. Kg2 {+12.37/25 4.4s}
Kg8 {-8.87/2 0.003s} 109. Bd3 {+13.19/20 2.1s} Kf7 {-8.90/29 4.3s}
110. Kg1 {0.00/22 6.1s} Kg8 {-8.87/34 4.3s} 111. Bf5 {+11.05/20 2.3s}
Kh8 {-8.85/25 4.1s} 112. Kf2 {+11.01/18 2.9s} Kg8 {-8.85/2 0.010s}
113. Be4 {+10.94/17 2.6s} Kf7 {-8.85/26 4.2s} 114. Kg3 {+11.47/21 2.2s}
Kg8 {-8.85/25 4.2s} 115. Kf4 {+11.23/21 2.3s} Kh8 {-8.87/26 4.2s}
116. Ke5 {+16.95/23 1.9s} Kg8 {-8.87/2 0s} 117. Kf6 {+11.16/18 1.9s}
Kh8 {-8.87/30 4.3s} 118. Kg6 {+11.16/32 2.2s} Kg8 {-8.87/2 0s}
119. Bd3 {+16.88/17 2.0s} Kh8 {-8.87/29 4.3s} 120. Kf6 {+11.09/18 2.1s}
Kg8 {-8.87/2 0s} 121. Ke7 {+12.71/35 2.1s} Kh8 {-8.87/2 0s}
122. Kd6 {+11.10/27 3.5s} Kg8 {-8.87/2 0s} 123. Bf5 {+11.10/30 2.7s}
Kf7 {-8.87/23 4.6s} 124. Kc5 {+17.29/16 3.9s} Kf6 {-8.85/26 4.5s}
125. Kd4 {+10.92/19 2.4s} Kf7 {-8.85/26 4.5s} 126. Ke5 {+10.98/22 2.3s}
Kg8 {-8.72/23 4.3s} 127. h7+ {+10.92/16 2.2s} Kg7 {-8.72/28 4.3s}
128. Kd6 {+10.84/50 2.1s} Kh8 {-8.72/28 4.3s} 129. Bc2 {+11.01/57 2.5s}
Kg7 {-8.72/2 0.001s} 130. Ke6 {0.00/26 7.1s} Kh8 {-8.72/31 4.4s}
131. Ke5 {+8.99/15 2.6s} Kg7 {-8.72/2 0s} 132. Bd3 {+9.16/18 2.3s}
Kh8 {-8.67/29 4.4s} 133. Kf4 {+8.74/17 6.4s} Kg7 {-8.67/2 0s}
134. Kg5 {+9.03/24 4.8s} Kh8 {-8.72/33 4.4s} 135. Kg4 {+8.75/16 2.0s}
Kg7 {-8.72/2 0s} 136. Bg6 {+8.77/17 3.8s} Kh8 {-8.72/34 4.6s}
137. Kf3 {+17.08/28 2.0s} Kg7 {-8.72/2 0s} 138. Bb1 {+8.75/23 2.6s}
Kh8 {-8.72/29 4.6s} 139. Kg4 {+8.71/17 3.5s} Kg7 {-8.72/2 0s}
140. Kf4 {+8.60/15 2.3s} Kh8 {-8.72/29 4.6s} 141. Bc2 {+8.66/20 2.3s}
Kg7 {-8.72/2 0s} 142. Ke3 {+8.60/25 2.3s} Kh8 {-8.72/28 4.7s}
143. Bf5 {0.00/22 6.4s} Kg7 {-8.72/2 0s} 144. Kd4 {+8.55/15 1.9s}
Kh8 {-8.68/28 4.8s} 145. Bb1 {0.00/23 6.1s} Kg7 {-8.68/2 0.001s}
146. Be4 {+8.56/33 2.3s} Kh8 {-8.68/29 4.8s} 147. Kc5 {+8.55/25 2.0s}
Kg7 {-8.68/2 0s} 148. Kd5 {+8.55/40 1.9s} Kh8 {-8.72/29 4.7s}
149. Ke5 {0.00/49 6.0s} Kg7 {-8.72/2 0s} 150. Kf4 {+8.68/49 1.9s}
Kh8 {-8.65/24 4.8s} 151. Bg6 {0.00/43 5.8s} Kg7 {-8.65/2 0.002s}
152. Ke3 {0.00/29 5.1s} Kh8 {-8.72/28 4.8s} 153. Kd3 {0.00/21 3.5s}
Kg7 {-8.72/2 0.002s} 154. Kc3 {+8.54/23 2.8s} Kh8 {-8.62/26 5.0s}
155. Kb4 {+8.54/25 2.3s} Kg7 {-8.62/2 0s} 156. Kb5 {+8.54/34 1.6s}
Kh8 {-8.67/29 4.9s} 157. Bb1 {+8.54/41 1.8s} Kg7 {-8.67/2 0s}
158. Kc6 {+8.54/47 1.9s} Kh8 {-8.72/27 4.9s} 159. Kd7 {0.00/34 5.7s}
Kg7 {-8.72/2 0s} 160. Ke8 {+8.52/17 1.9s} Kh8 {-8.67/32 5.0s}
161. Bg6 {+8.52/26 2.1s} Kg7 {-8.67/2 0s} 162. Kd7 {+8.52/35 1.9s}
Kh8 {-8.63/28 5.0s} 163. Bc2 {0.00/42 5.7s} Kg7 {-8.63/2 0.001s}
164. Kd6 {+8.51/36 2.2s} Kh8 {-8.62/25 5.0s} 165. Bd3 {+8.51/42 2.0s}
Kg7 {-8.62/2 0s} 166. Ke6 {0.00/36 5.6s} Kh8 {-8.45/25 5.3s}
167. Kd5 {+8.50/29 1.8s} Kg7 {-8.45/2 0.002s} 168. Bf5 {+8.51/40 2.0s}
Kh8 {-7.80/21 7.1s} 169. Ke4 {+8.50/39 1.7s} Kg7 {-7.80/2 0.001s}
170. Kf3 {+9.03/49 1.8s} Kh8 {0.00/18 5.5s} 171. Kf4 {+12.86/55 3.5s}
Kg7 {0.00/2 0s} 172. Kg4 {+10.97/22 4.2s} Kh8 {0.00/59 0.55s}
173. Kf3 {+8.61/17 3.4s} Kg7 {0.00/2 0s} 174. Bc2 {+8.51/32 5.4s}
Kh8 {0.00/59 0.004s} 175. Kg3 {+8.50/18 2.5s} Kg7 {0.00/2 0s}
176. Bb1 {+8.66/39 1.9s} Kh8 {0.00/59 0.002s}
177. Kg2 {+8.50/26 3.4s, Draw by fifty moves rule} 1/2-1/2