Author: Richard Pijl
Date: 13:00:49 12/15/03
Go up one level in this thread
On December 15, 2003 at 04:04:27, martin fierz wrote:
>On December 15, 2003 at 02:11:54, Richard Pijl wrote:
>
>>On December 15, 2003 at 01:12:03, martin fierz wrote:
>>
>>>On December 14, 2003 at 17:30:49, Richard Pijl wrote:
>>>
>>>>On December 14, 2003 at 15:18:46, Richard Pijl wrote:
>>>>
>>>>>In a very recent game between Baron and Amateur (time control 45 10) on ICC, the
>>>>>following position occurred:
>>>>>
>>>>>[D]7k/2B2pp1/2n1b3/P2p2Pp/2p4n/4NP2/5K2/5B2 w - - 0 55
>>>>>
>>>>>White is two pawns down, both passers. As compensation, White has a pair of
>>>>>bishops. Understandably, Amateur showed a big plus score (+3.4), however The
>>>>>Baron thought is was almost drawn (-0.34). What do your engines think about
>>>>>this?
>>>>
>>>>Together with Dieter Bürßner we've tried to find a win for Black. We did not
>>>>succeed, but ofcourse we could not examine all lines. Can someone else find a
>>>>winning line?
>>>
>>>it would help if you posted your analysis :-)
>>>i don't see how white holds on after 1.a6 Nf5, eg. 2.Bb8 Nxe3 3.Kxe3 Bc8 4.a7
>>>Bb7. what did you find there?
>>
>>The reason that we've been looking at this position is that I/we could not
>>believe that either.
>>
>>If you replace 2Bb8 in your line by 2.Bb6, you end up with a game position.
>i see...
>
>>We've played it out and tried some alternatives.
>>The problem was we didn't find something for black to break through. At least
>>none that could not be avoided by white in an earlier stage. We even ended up
>>with a winning line for white once!
>>
>>I'll post some positions we've reached (semi-fortresses) later today. I have to
>>go to work now.
>
>...i'm looking forward to it - it's an interesting position for sure. however,
>i'm pretty sure that your evaluation function is rather lucky if it turns out
>that it's nearly-draw-score is in fact correct. this is not the kind of position
>that looks drawish to me at all; under normal circumstances the 2 bishops won't
>compensate for 2 pawns, even with a pawn on a7.
>
You're right about the faulty eval. I found two bugs in the Baron that caused
this low/high score for this position. After correcting it, the score is (after
some search) at -0.70 from white's perspective.
One of the key positions may be the game position after move 64 of white:
[D]8/Pb1B1pp1/6k1/3p1nP1/2p2P1p/2K5/5B2/8 b - -
The Baron (corrected version, 1CPU version on AMD MP 2000+) says about this
position:
14(40)& 10:53.14 183537649 +1.02 Nf5-g3 Kc3-d4 Bb7-a8 Kd4-e3 f7-f6 Bd7-e8
Kg6-h7 Be8-d7 Ba8-b7 Ke3-d4 Kh7-g6 g5xf6
g7xf6 Bf2-e1 Kg6-h5 Kd4-c5 Ng3-e4 Kc5-b6
h4-h3 Kb6xb7 h3-h2 a7-a8Q h2-h1Q Kb7-c6
Qh1xe1
14(41)& 11:38.72 198207567 +1.15 Bb7-a8 Kc3-b4 Nf5-g3 Bf2-e3 f7-f5 Bd7-e8
Kg6-h7 Be3-f2 g7-g6 Be8-b5 Ng3-e2 Bf2xh4
Ne2xf4 Bb5-d7 Nf4-d3
14(41). 15:52.56 257308662 +1.15 Bb7-a8 Kc3-b4 Nf5-g3 Bf2-e3 f7-f5 Bd7-e8
Kg6-h7 Be3-f2 g7-g6 Be8-b5 Ng3-e2 Bf2xh4
Ne2xf4 Bb5-d7 Nf4-d3
Black's possibilities seem limited, but perhaps a win is possible.
Richard.
>>>>>The game ended in a draw after many more moves.
>>>>
>>>>Full game score:
>>>>
>>>>[Event "ICS rated standard match"]
>>>>[Site "chessclub.com"]
>>>>[Date "2002.12.14"]
>>>>[Round "-"]
>>>>[White "thebaron"]
>>>>[Black "Amateur"]
>>>>[Result "1/2-1/2"]
>>>>[WhiteElo "2429"]
>>>>[BlackElo "2520"]
>>>>[TimeControl "2700+10"]
>>>>
>>>>1. e4 e5 2. Nf3 Nc6 3. Bb5 a6 4. Ba4 Nf6 5. O-O b5 6. Bb3 Bb7 7. Re1 Bc5 8.
>>>>c3 d6 9. a4 h6 10. d4 Bb6 11. axb5 axb5 12. Rxa8 Qxa8 13. dxe5 Nxe5 14. Bc2
>>>>Qa7 15. Nd4 O-O 16. Na3 b4 17. Nab5 Qa8 18. cxb4 Nxe4 19. Re3 Re8 20. Bb1
>>>>Bd5 21. b3 Qb7 22. f3 Nf6 23. Kh1 Bxd4 24. Nxd4 Qxb4 25. Bc2 Bb7 26. Re1
>>>>Ra8 27. Be3 Ra2 28. Bb1 Rb2 29. Re2 Rxe2 30. Qxe2 Nd5 31. Qd2 Qb6 32. Bg1
>>>>Nf6 33. Bc2 Qa6 34. Qe1 Qa8 35. h3 Qa3 36. Nf5 Qb2 37. Ne3 Nc6 38. Qe2 Qe5
>>>>39. Qc4 Qa5 40. Bf5 d5 41. Qa4 Qxa4 42. bxa4 Ne7 43. Bd3 c5 44. Bh2 c4 45.
>>>>Bf1 Nc6 46. Kg1 Bc8 47. g4 Kh8 48. Kf2 Bd7 49. h4 Be6 50. Bc7 h5 51. g5 Ne8
>>>>52. Bb6 Nd6 53. Bc7 Nf5 54. a5 Nxh4 { diagram position } 55. a6 Nf5 56. Bb6 Nxe3
>>>>57. Kxe3 Bc8
>>>>58. a7 Bb7 59. Kd2 Kh7 60. Bh3 Kg6 61. f4 Ne7 62. Bd7 Nf5 63. Kc3 h4 64.
>>>>Bf2 Ba8 65. Kb4 Ng3 66. Be3 Nf5 67. Bg1 Ng3 68. Bg4 f5 69. gxf6 Kxf6 70.
>>>>Bd4+ Kg6 71. Be5 Ne4 72. Bd7 Nf6 73. Bh3 Kf7 74. Kb5 Ke7 75. Bd4 Nh5 76.
>>>>Bc5+ Ke8 77. Kb6 Kd8 78. Bf2 Ng3 79. Bd4 Ne4 80. Bxg7 c3 81. f5 c2 82. Bh6
>>>>d4 83. f6 Nxf6 84. Bc1 Ne4 85. Bf1 Nc3 86. Kc5 Na2 87. Bg5+ Kc7 88. Kxd4
>>>>Bc6 89. Ke5 Kb7 90. Bh3 Kxa7 91. Be3+ Kb7 92. Kf4 Nc3 93. Kg5 Nd1 94. Bd2
>>>>Nf2 95. Kxh4 Nxh3 96. Kxh3 Kb6 97. Be3+ Kb5 98. Bd2 Kc4 99. Be3 Kd3 100.
>>>>Bf4 Ke2 101. Kg4 Bg2 102. Kf5 Kd3 103. Ke6 Kc3 104. Be5+ Kb3 105. Bf4 Ka2
>>>>106. Be3 Kb3 107. Ke5 Kb2 108. Bd4+ Kb1 109. Be3 Bf1 110. Kd5 Kb2 111. Bd4+
>>>>Kb1 112. Be3 Be2 113. Ke5 Kb2 114. Bd4+ Kb1 115. Be3 Kb2 116. Bd4+ Ka2 117.
>>>>Be3 Kb1 118. Kd6 Kb2 119. Ke6 Bc4+ 120. Ke5 Bd3 121. Bd4+ Kb1 122. Be3 Be2
>>>>123. Kd6 Kb2 124. Ke6 Bc4+ 125. Ke5 Ba6 126. Bd4+ Ka2 127. Be3 Kb1 128. Kd5
>>>>Bf1 129. Kd6 Kb2 130. Kc6 Be2 131. Kc7 Bf3 132. Bd4+ Kb1 133. Be3 Kb2 134.
>>>>Kb8 Kb1 135. Kc7 Bg4 136. Kd6 Kb2 137. Bd4+ Kb3 138. Be3 Kc4 139. Ke5 Kd3
>>>>140. Kf4 Bh5 141. Bc1 Ke2 142. Ke5 Kd1 143. Be3 Bf3 144. Ke6 Ke2 145. Bf4
>>>>Kd3 146. Kf5
>>>>{Game drawn by the 50 move rule} 1/2-1/2
>>>>
>>>>>Richard
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