Not logged inRybka Chess Community Forum
Up Topic The Rybka Lounge / Computer Chess / How many more decades of Opposite Colored Bishop blindness
- By MrKris (***) Date 2020-11-01 05:00 Edited 2020-11-01 07:55
From my event using the new opening book here: http://rybkaforum.net/cgi-bin/rybkaforum/topic_show.pl?tid=33700

Crystal begins a stunning sacrificial attack with 12.Re4!!.

[Event "G/5'+2'' 4GBh Sy.6"]
[Site "R7 2700X 8ths | concur.2"]
[Date "2020.10.30"]
[Round "10"]
[White "Crystal-201019"]
[Black "Cfish-201024-Pure"]
[Result "1-0"]
[BlackElo "2400"]
[WhiteElo "2400"]
[TimeControl "300+2"]
[SetUp "1"]
[FEN "rnbqk2r/p1pp1ppp/5n2/1Bb1p3/4P3/2N5/PPPPNPPP/R1BQK2R b KQkq - 0 1"]
[Termination "normal"]
[PlyCount "115"]
[WhiteType "human"]
[BlackType "human"]

1. ... c6 {-0.83/29 0 5.8s} 2. Bc4 {+0.78/26 0 16s} O-O {-0.92/30 0 4.7s}
3. O-O {+0.84/24 0 9.4s} d5 {-0.87/28 0 4.3s} 4. Bb3 {+0.78/25 0 6.0s} Ba6
{-0.87/28 0 5.4s} 5. exd5 {+0.80/25 0 5.5s} cxd5 {-1.06/30 0 9.0s} 6. d3
{+0.81/22 0 4.1s} d4 {-1.20/27 0 6.6s} 7. Na4 {+0.97/23 0 10s} Nbd7
{-1.13/29 0 11s} 8. c3 {+0.96/21 0 5.5s} Bd6 {-1.25/28 0 16s} 9. Re1
{+1.05/21 0 19s} Qc7 {-1.14/24 0 3.9s} 10. Ng3 {+0.96/20 0 6.6s} h6
{-1.26/30 0 44s} 11. Nf5 {+1.30/21 0 5.6s} Rfe8 {-1.26/28 0 2.7s}
12. Re4 {+1.58/23 0 13s !! ---Exchange offer. White's win seems quite likely.---}
[FEN "r3r1k1/p1qn1pp1/b2b1n1p/4pN2/N2pR3/1BPP4/PP3PPP/R1BQ2K1 b - - 3 12"]

12... Nf8 {-1.68/33 0 43s} (12. .. Nxe4 {?} 13. Qg4 {!! +- ---Making it a rook
sac.!---} Ng5 (13. .. Bf8 14. Nxh6+ Kh7 15. Nxf7 Kg8 16. Nd6+ Bc4 17. Nxe8
Rxe8 18. Bxc4+ Qxc4 19. dxc4) 14. Bxg5 hxg5 15. Qxg5 Bf8 16. Nh6+ Kh7 17.
Nxf7 Nf6 18. Qh4+ Kg6 19. Qg5+ Kh7 20. Qf5+ g6 21. Qxf6 Be7 22. Qxa6) 13.
Rg4 {+1.84/22 0 2.9s !! ---And again.---} Nxg4 {-1.71/31 0 3.2s} (13. ..
Ne6 14. Nxg7 {!! +-} Nxg4 (14. .. Nxg7 15. Rg6 {! ---An important
in-between move.---} Qe7 16. Bxh6 Kh7 17. Rxg7+ Kxh6 18. Rxf7 Qd8 19. Qf3
Rf8 20. Qh3+ Nh5 21. Rd7 Qf6 22. g4) 15. Nxe8 Rxe8 16. Qxg4+ Kh7 17. Qe4+
Kg7 18. Bd2) (13. .. g6 14. Nxh6+ {+-} Kg7 15. Nxf7 Ne6 (15. .. Nxg4 16.
Qxg4 Bc8 17. Bh6+ Kg8 18. Nxd6+ Be6 19. Nxe8 Rxe8 20. Bxe6+ Rxe6 21. Bxf8))
14. Qxg4 {+1.91/25 0 7.2s} Ne6 {-2.13/32 0 8.1s} (14. .. g6 {? +-} 15.
Nxh6+ Kg7 16. Nxf7) 15. Bxh6 {+1.95/24 0 5.6s} g6 {-2.24/32 0 6.6s} (15. ..
Bf8 16. Nc5 {!! +- ---White will be a rook down to deflect black's Qc7 or
Bf8 or Ne6 defending its king area.---} Qxc5 (16. .. Nxc5 17. Bxg7 {Mate in
7}) 17. Bxg7 Bxg7 (17. .. Nxg7 18. Qg6 {!}) 18. Bxe6 Qf8 19. Nh6+ Kh7 20.
Qf5+ {!} Kxh6 21. g4 Bf6 22. Qxf6+ Kh7 23. Bf5+ Kg8 24. Qxa6 {---White has
3 pawns for the exchange.---}) 16. Ng7 {+2.04/24 0 5.3s} Nxg7 {-2.69/35 0
49s} (16. .. Bxd3 {!?} 17. Nxe6 fxe6 18. Bxe6+ Rxe6 19. Qxe6+ Kh7 20. cxd4
{!} Bf5 (20. .. exd4 {?} 21. Rc1 Qe7 22. Qxe7+ Bxe7 23. Bf4) (20. .. Kxh6
{?} 21. Qh3+ Kg7 22. Qxd3) 21. Qd5 Re8 22. Be3 exd4 23. Bxd4 Be4 24. Qb3
Bxh2+ 25. Kh1 {---White is 2 pawns up but must defend carefully. Cfish
gives white +2.20 at 4 mins.---}) 17. Qxg6 {+2.02/24 0 4.5s} Bf8 {-2.67/28
0 3.6s} 18. Qxa6 {+2.14/22 0 6.1s ---White has 3 pawns for the
exchange.---} Ne6 {-2.49/29 0 11s} 19. Bd2 {+2.24/22 0 4.3s} Bg7 {-2.42/26
0 3.2s} 20. Re1 {+2.08/23 0 7.1s} Rad8 {-2.29/28 0 6.0s} 21. Qb5 {+1.98/23
0 6.4s} dxc3 {-2.65/29 0 7.3s} 22. bxc3 {+2.16/27 0 7.2s} Qd6 {-2.89/31 0
13s} 23. Be3 {+2.07/25 0 9.0s} Qxd3 {-2.82/29 0 3.5s} 24. Qxd3 {+2.22/25 0
12s} Rxd3 {-3.10/32 0 5.5s} 25. Bxa7 {+2.36/24 0 5.9s} Ra8 {-2.86/28 0
3.6s} 26. Bb6 {+2.41/23 0 4.6s} Rd6 {-2.83/27 0 4.1s} 27. Be3 {+2.37/23 0
8.5s} Ra5 {-2.69/29 0 6.4s} 28. g3 {+2.33/23 0 6.5s} e4 {-2.66/25 0 2.8s}
29. Bc1 {+2.38/23 0 6.8s} Re5 {-2.69/26 0 3.7s} 30. Kf1 {+2.34/24 0 23s}
Ra6 {-2.85/28 0 13s} 31. Bd2 {+2.37/25 0 28s} Kh7 {-3.01/28 0 4.4s} 32. h4
{+2.47/22 0 2.5s} Rd6 {-2.82/27 0 3.2s} 33. Be3 {+2.50/23 0 9.0s} Ra5
{-3.21/30 0 8.0s} 34. Bc1 {+2.71/26 0 22s} f5 {-2.99/28 0 5.1s} 35. g4
{+2.79/23 0 3.2s} Bh6 {-3.88/30 0 7.5s} 36. Ba3 {+3.01/25 0 16s} Rd2
{-3.42/29 0 3.6s} 37. g5 {+3.07/22 0 3.4s} Bf8 {-3.64/28 0 6.6s} 38. Bc1
{+2.62/23 0 6.0s} Rd6 {-3.94/28 0 5.3s} 39. Be3 {+3.02/24 0 19s} Re5
{-3.95/28 0 8.5s} 40. Nb6 {+3.54/22 0 2.8s} Rd8 {-3.15/25 0 1.0s} 41. a4
{+3.05/23 0 6.7s} Bg7 {-4.86/30 0 14s} 42. Re2 {+3.49/24 0 9.7s} Nc5
{-4.75/25 0 1.8s} 43. Bf7 {+3.68/21 0 1.6s} Nd3 {-4.81/25 0 0.89s} 44. Nc4
{+3.76/20 0 3.3s} Re7 {-4.43/22 0 1.2s} 45. g6+ {+3.84/19 0 2.6s} Kh8
{-4.41/13 0 0.001s} 46. Bg5 {+3.49/20 0 2.6s} Rb8 {-4.38/23 0 1.9s} 47. Kg2
{+3.43/19 0 3.0s} f4 {-5.11/24 0 8.3s} 48. Kh2 {+3.88/20 0 3.4s} f3
{-5.75/24 0 3.3s} 49. Ra2 {+4.59/19 0 1.7s} Rd7 {-6.10/23 0 2.3s} 50. a5
{+4.46/19 0 1.9s} Bxc3 {-6.15/21 0 0.34s} 51. a6 {+4.97/18 0 1.4s} Bd4
{-6.17/23 0 0.97s} 52. Ne3 {+5.56/17 0 1.6s} Rb2 {-4.17/20 0 0.65s} 53.
Rxb2 {+6.61/18 0 1.7s} Bxb2 {-7.27/21 0 2.7s} 54. h5 {+7.67/17 0 1.4s} Ra7
{-9.37/23 0 4.8s} 55. h6 {+8.92/21 0 1.8s} Rxa6 {-6.89/21 0 0.98s} 56. Nf5
{+9.76/20 0 3.4s} Rxg6 {-11.90/21 0 0.75s} 57. Bxg6 {+11.21/18 0 1.3s} Nxf2
{-14.59/23 0 3.4s} 58. Kg3 {+11.23/19 0 1.5s} Nd1 {-16.11/23 0 3.3s, White
wins by adjudication} 1-0



Note in the above game how strong Crystal's bishop pair was, particularly its dark squared bishop, which it left on c1 until 15.Bxh6 - very efficient.

In the colors reversed Cfish as white, a clear pawn up from the counter-gambit, gave up its bishop pair with 9.Bg5 and 10.Bx(N)f6 and then its 13.Ne4 allowed Opposite-Colored Bishops after black's obvious 13...Bxe4 (although there were other pieces each side in this case that did not help white). [Event "G/5'+2'' 4GBh Sy.6"]
[Site "R7 2700X 8ths | concur.2"]
[Date "2020.10.30"]
[Round "10"]
[White "Cfish-201024-Pure"]
[Black "Crystal-201019"]
[Result "1/2-1/2"]
[TimeControl "300+2"]
[SetUp "1"]
[FEN "rnbqk2r/p1pp1ppp/5n2/1Bb1p3/4P3/2N5/PPPPNPPP/R1BQK2R b KQkq - 0 1"]
[Termination "adjudication"]
[PlyCount "236"]
[WhiteType "program"]
[BlackType "human"]

1. ... c6 2. Bc4 O-O 3. O-O d5 4. Bb3 Ba6 5. exd5 cxd5 6. d3 d4 7. Na4 Bd6
8. Ng3 Bb7 9. Bg5 h6 10. Bxf6 Qxf6 11. Qg4 Kh8 12. c3 Na6 13. Ne4 {+1.28/31 0 17s ---An advantageous eval. but Cfish has already allowed a drawish game - OCB blindness.---} Bxe4
{-1.04/26 0 31s} 14. dxe4 {---Very disappointing compared to the colors reversed above: white has no attack and its pawn up looks unlikely to win.---}
[FEN "r4r1k/p4pp1/n2b1q1p/4p3/N2pP1Q1/1BP5/PP3PPP/R4RK1 b - - 0 14"]

14... Nc5 15. Nxc5 Bxc5 16. Bd5 Rab8 17. Qe2 a5 18. Rad1 g6 19. g3 h5 20.
Rd3 Kg7 21. b3 Rbc8 22. cxd4 Bxd4 23. h4 Rc7 24. Kg2 Rfc8 25. Rfd1 Qb6 26.
Bc4 a4 27. Rf3 axb3 28. Bxb3 f6 29. Rfd3 Qa6 30. R1d2 Rc6 31. Bd1 R8c7 32.
a4 Qb7 33. Ra2 Rc1 34. Kh2 Rb1 35. Rdd2 Bc3 36. Rd6 Bd4 37. Qf3 Rf7 38. Rc2
Rb2 39. Rxb2 Qxb2 40. Kg2 Qc3 41. Qxc3 Bxc3 42. Rc6 Be1 43. Be2 Rd7 44. Rc5
Bb4 45. Rc8 Ra7 46. Bb5 Ba5 47. f3 Rc7 48. Rxc7+ {+0.87/48 0 2.8s} Bxc7
{-0.50/31 0 0.84s ---Obviously an OCB draw, but it takes another 71 moves.---} 49. g4 Kf7 50. Bc6
Ke7 51. Bb5 Bb6 52. Be2 Ke6 53. Bc4+ Ke7 54. Bb5 Ba5 55. Kf1 Bc3 56. Ke2
Bb4 57. Ba6 Ba5 58. Bc4 Bb4 59. Kd1 Ba5 60. Ke2 Bb4 61. Ba6 Ba5 62. Bb5 Bb4
63. Kd1 Ba5 64. Bc4 Bb4 65. Bd5 Ba5 66. Bc4 Bb4 67. Bb5 Ba5 68. Bc6 Bb4 69.
Bb7 Ba5 70. Bd5 Bb4 71. Ke2 Ba5 72. Kd1 Bb6 73. Ke2 Ba5 74. Bb7 Bb4 75. Kf2
Ba5 76. Bc8 Kf7 77. Ba6 Ke7 78. Ke2  Bb4  79. Bc4  Ba5  80. Bd5
{ } Bb4 81. Bc6 Ba5 82. gxh5 gxh5 83. Bb5 Bb4 84. Kd1 Bc3
85. Bd3 Bb4 86. Bc4 Ba5 87. Bd5 Bc3 88. Ke2 Ba5 89. Bc4 Bb4 90. Bd5 Bc3 91.
Kd1 Bb4 92. Bb3 Ba5 93. Bc4 Bb4 94. Bb5 Ba5 95. Bc4 Bb4 96. Be2 Ke6 97. Bd3
Ke7 98. Bc4  Bc3 99. Ba2 Ba5 100. Bd5 Bb4 101. Bb3 Ba5
102. Ba2 Bb4 103. Bg8 Ba5 104. Bh7 Kf7 105. Bf5 Bb4 106. Bd7 Ba5 107. Ke2
Bb4 108. Bb5 Ke7 109. Ba6 Ba5 110. Bb7 Bb4 111. Bc8 Kf7 112. Bf5 Ba5 113.
Kd1 Bc3 114. Bc8 Ba5 115. Bd7 Ke7 116. Bf5 Kf7 117. Bd7
Ke7 118. Bc8 Kf7 {0.0037
4.5s} 119. Ke2 {+0.04/33 0 1.3s, Draw by adjudication} 1/2-1/2
- By MrKris (***) Date 2020-11-15 04:30
Stockfish 'gets' this OCB ending, AllieStein not so much

https://tcec-chess.com/#div=frc2la&game=10&season=19
TCEC S19 - FRC2 League A , Round: 5.2
White: AllieStein v0.8-120f959_net-15.0
Black: Stockfish 202011101829_nn-c3ca321c51c9
Result: 1/2-1/2

Stockfish said 0.00 for all its moves 3...Bf6, diagram, to the end 102...Be4, 100 consecutive moves!? 
rqn1bknr/pp1p1ppp/4pb2/2p5/1PP5/5N2/P2PPPPP/RQNBBK1R w KQkq - 2 4


AllieStein's evaluation went UP after it was just OCB vs OCB and pawns, no other pieces:
[FEN "8/6p1/b3kp1p/P3p2P/1B6/4KP2/6P1/8 b - - 0 41"]

{after 41. Bxb4, last other piece exchanged} 41... f5 42. g3 {<<< 0.09} f4+ 43. gxf4 Bb7 44. fxe5 {<<< 0.33} Kxe5 45. Bc3+ Kf5 46. Bxg7 Kg5 47. Be5 Kxh5
48. Bh2 Kh4 49. f4 {<<< 0.50} Kg4 50. Kd4 Kf5 51. Kc5 Bc8 52. Kd5 Bb7+ 53. Kd6 Kf6 54. Kc5 {<<< 0.81} h5 55. Kb6 Bh1
56. Kc7 h4 57. a6 Be4 58. Kd6 Kf5 59. Ke7 Bd5 60. Kd6 {<<< 0.87} Ba8 61. Kd7 {<<< 0.90} Bf3 62. Ke7 Bd5 63. Kd6 Be4
64. Kc7 Kf6 65. Kd7 Bf5+ 66. Kd6 Bg4 67. Kc7 Kf5 68. Kd7 Bf3 69. Kc7 Be4 70. Kd8 Kg4 71. a7 Bh1
72. Ke7 Kf5 73. Kd7 Be4 74. Kc7 Bf3 75. Kd6 Bg2 76. Ke7 Be4 77. Kf7 {<<< 0.87} Bf3 78. Ke7 Be4 79. Kd7 Bh1
80. Kd6 Bf3 81. Kc7 Be4 82. Kc8 Ke6 83. Kc7 Bd5 84. Kb8 Kf5 85. Kc8 Be6+ 86. Kc7 Bd5 87. Kd6 Bf3
88. Kd7 Be4 89. Ke7 Bg2 90. Kf8 {<<< 0.64} Bd5 91. Ke8 Bg2 92. Kf8 Bd5 93. Kg7 Bf3 94. Kh7 Bg2 95. Kg8 Bb7
96. Kf7 Ba8 97. Ke8 Bd5 98. Kf8 Be4 99. Ke8 Bc6+ 100. Kf7 Be4 101. Ke8 Bd5 102. Ke7 Be4 {1/2-1/2}
Up Topic The Rybka Lounge / Computer Chess / How many more decades of Opposite Colored Bishop blindness

Powered by mwForum 2.27.4 © 1999-2012 Markus Wichitill