Author: Dieter Buerssner
Date: 14:22:55 03/04/04
Inspired by Peter's post, where PM resigned in a draw position
(http://www.talkchess.com/forums/1/message.html?352360) and some private
discussion later on, I digged up a position from one of my test games
Yace-Crafty, which you might find interesting to ponder about. (Some) engines
may have a very hard time, to win this. Especially, when they are too clever,
and see already a draw-score after Nxh4 (they would not try to make progress).
Even if they don't score it as 0.0, they may easily fail to win. Even when they
have rather clever awareness of the draw threats. They may see a Zugzwang b6-b7
(which will be delayed just to the start of qsearch), which will actually result
in a stalemate, but will feel happy, that the wrong colored B-theme is gone
away.
[D] 8/1p6/3p4/P3kn2/6KP/P7/3B4/8 b - - 0 47
White just played h4. Crafty showed 0.0 score for Nxh4. But it is actually a
forced mate. With some analysis I get:
11.01 0:00 +M47 50.Kxh4 Ke4 51.Kg4 d5 52.Kg3 Kd3 53.Bg5 Ke4 54.Bf4 Kd3
55.Kf2 Kd4 56.Bg5 Kd3 57.Kf3 d4 58.Bh4 Kc4 59.Ke2 Kc3 60.Bg3 Kc4 61.Kd2 Kd5
62.Bb8 Kc6 63.Ba7 (245.302) 445.1
11.15 0:01 +M47 50.Kxh4 Ke4 51.Kg4 d5 52.Kg3 Kd3 53.Bg5 Ke4 54.Bf4 Kd3
55.Kf2 Kd4 56.Bg5 Kd3 57.Kf3 d4 58.Bh4 Kc4 59.Ke2 Kc3 60.Bg3 Kc4 61.Kd2 Kd5
62.Bb8 Kc6 63.Ba7 (714.315) 468.7
12.01 0:01 +M47 50.Kxh4 Ke4 51.Kg4 d5 52.Kg3 Kd3 53.Bg5 Ke4 54.Bf4 Kd3
55.Kf2 Kd4 56.Bg5 Kd3 57.Kf3 d4 58.Bh4 Kc4 59.Ke2 Kc3 60.Bg3 Kc4 61.Kd2 Kd5
62.Bb8 Kc6 63.Ba7 (714.316) 468.7
12.15 0:07 +M47 50.Kxh4 Ke4 51.Kg4 d5 52.Kg3 Kd3 53.Bg5 Ke4 54.Bf4 Kd3
55.Kf2 Kd4 56.Bg5 Kd3 57.Kf3 d4 58.Bh4 Kc4 59.Ke2 Kc3 60.Bg3 Kc4 61.Kd2 Kd5
62.Bb8 Kc6 63.Ba7 (2.909.086) 386.9
13.01 0:07 +M47 50.Kxh4 Ke4 51.Kg4 d5 52.Kg3 Kd3 53.Bg5 Ke4 54.Bf4 Kd3
55.Kf2 Kd4 56.Bg5 Kd3 57.Kf3 d4 58.Bh4 Kc4 59.Ke2 Kc3 60.Bg3 Kc4 61.Kd2 Kd5
62.Bb8 Kc6 63.Ba7 (2.909.087) 386.9
(the mate will be shorter).
A position, where engines still may fail later (because of the idea mentioned
above):
[D] 8/1pk5/8/P2pK3/P2B4/8/8/8 w - - 0 57
Kxd5?? Kb8= (Again, many engines will resign here in a drawn position).
So, it might be interesting for you, to try out the first position with your
engine, and see, if it can win.
I "attach" the tree of variations, which yielded in the mate score.
Regards,
Dieter
[Event "Computer chess game 0 600 +5 0 0"]
[Site "?"]
[Date "2004.02.10"]
[Round "1"]
[White "Yace 0.99.83nh2"]
[Black "crafty"]
[WhiteElo "0"]
[BlackElo "0"]
[ECO "E97"]
[Result "1-0"]
1. c4 {0.08s} Nf6 {0.25s} 2. Nc3 {0.04s} g6 {0.02s} 3. e4
{0.03s} d6 {0.01s} 4. d4 {0.02s} Bg7 {0.02s} 5. Nf3 {0.02s}
O-O {0.04s} 6. Be2 {0.03s} e5 {0.03s} 7. O-O {0.01s} Nc6
{0.25s} 8. Be3 {0.02s} Ng4 {0.05s} 9. Bg5 {0.03s} f6
{0.05s} 10. Bc1 {0.03s} Nh6 {0.02s} 11. d5 {0.01s} Ne7
{0.03s} 12. b4 {0.03s} Nf7 {0.04s} 13. Qc2 {0.54/10 42.75s}
f5 {28.81s} 14. Ng5 {0.51/10 23.17s} Nxg5 {28.04s} 15. Bxg5
{0.48/9 35.26s} h6 {23.27s} 16. Bd2 {0.46/10 24.08s} fxe4
{22.07s} 17. Qxe4 {0.42/9 24.75s} Bf5 {22.23s} 18. Qh4
{0.36/9 20.06s} Nc6 {22.40s} 19. Qxd8 {0.40/10 19.62s} Nxd8
{20.63s} 20. c5 {0.41/10 19.20s} Nf7 {20.60s} (20... Rf7)
21. Rfe1 {0.39/9 18.80s} a5 {20.13s} (21... e4) 22. Nb5
{0.55/10 17.78s} Rfc8 {19.29s} 23. cxd6 {0.56/10 18.04s}
cxd6 {19.00s} (23... Nxd6) 24. bxa5 {0.63/11 9.78s} Rc2
{18.52s} 25. Bb4 {0.57/10 17.53s} Rb2 {19.34s} (25... Rxe2)
26. a3 {0.45/11 13.22s} Rxe2 {18.06s} 27. Rxe2 {0.60/13
16.55s} Bd3 {17.57s} 28. Nc7 {0.67/12 16.60s} Rc8 {16.99s}
29. Rd2 {0.69/13 15.05s} Rxc7 {17.88s} 30. Rxd3 {0.68/13
8.96s} e4 {16.62s} 31. Rdd1 {0.78/13 15.87s} Bxa1 {16.83s}
32. Rxa1 {0.84/13 15.56s} Kf8 {15.70s} (32... Rc4) 33. Re1
{0.90/13 9.54s} Rc4 {15.41s} 34. h3 {0.92/12 15.13s} h5
{17.02s} 35. f3 {0.92/12 14.84s} exf3 {14.62s} 36. gxf3
{0.93/12 14.56s} Rd4 {14.43s} 37. Re6 {0.90/12 8.36s} Rxd5
{14.25s} 38. Rxg6 {0.99/12 7.22s} Ke7 {14.28s} (38... Rf5)
39. Kf2 {0.98/12 13.69s} Rf5 {13.66s} (39... Rd3) 40. Kg3
{0.95/11 13.88s} Rxf3+ {17.68s} 41. Kxf3 {1.09/15 10.72s}
Ne5+ {13.19s} 42. Kf4 {1.08/16 11.00s} Nxg6+ {12.77s}
43. Kg5 {1.08/16 13.31s} Ne5 {12.73s} 44. Kxh5 {1.11/15
13.10s} Ke6 {13.27s} 45. Kg5 {1.11/15 12.82s} Nf3+ {12.23s}
(45... d5) 46. Kf4 {1.14/15 12.59s} Nh4 {12.88s} 47. Kg4
{1.14/15 11.11s} Nf5 {11.68s} 48. Bd2 {1.20/14 12.38s} Ke5
{12.27s} (48... d5) 49. h4 {1.66/14 6.18s} Nxh4 {12.72s}
(49... Ke6) 50. Kxh4 {2.96/13 20.71s} Kf6 {12.30s}
(50... Kd4 51. Bf4 {13s}) (50... d5 {1:11m} 51. Kg3 {12s}
d4 {4s} (51... Ke4 {26s} 52. Bg5 {53s} Kf5 {23s} (52... Kd3
{33s} 53. Kf4 {6s} d4 {0s} (53... Kd4 {1:48m} 54. Bd8 {3s})
54. Bd8 {8s}) (52... Ke5 {41s} 53. Be3 {1s}) 53. Be3 {1s})
(51... Kd4 {37s} 52. Bf4 {3s} Kd3 {3s} 53. Kf2 {1s})
(51... Kd6 {11s} 52. Be3 {1s}) 52. Bf4+ {11s} Kd5 {6s}
(52... Ke4 {25s} 53. Bb8 {6s} Ke3 {6s} 54. Ba7 {1s} Kd3
{11s} 55. Kf3 {1s} Kc3 {6s} 56. Ke2 {4s}) 53. Bc7 {4s} Kc4
{14s} (53... Kc6 {15s} 54. Bb6 {1s}) (53... Ke4 {23s}
54. Kf2 {25s}) (53... d3 {23s} 54. Kf2 {2s}) 54. Kf3 {2s}
Kb3 {11s} (54... Kc3 {15s} 55. Ke4 {21s} d3 {2s} 56. Bf4
{3s}) (54... Kd3 {20s} 55. Bg3 {42s} Kc3 {8s} (55... Kc4
{15s} 56. Ke2 {4s}) 56. Ke2 {1s} d3+ {9s} 57. Kd1 {2s})
(54... d3 {14s} 55. Ke3 {1s}) 55. Ke4 {1s} Kc4 {7s} 56. Bd8
{12s} d3 {4s} 57. Ke3 {1s} Kc3 {5s} 58. Bg5 {7s} d2 {1s}
59. Ke2 {1s} d1=Q+ {13s} 60. Kxd1 {3s}) (50... Ke4 {43s}
51. Kg4 {3s} d5 {5s} (51... Kd5 {11s} 52. Kf5 {3s} Kc6 {9s}
53. Be3 {1s}) (51... Kd3 {10s} 52. Bf4 {7s}) (51... Kd4
{54s} 52. Kf5 {3s} d5 {2s} 53. Bg5 {6s}) 52. Kg3 {9s} d4
{1s} 53. Kf2 {10s}) (50... Kd5 {23s} 51. Be3 {6s} Ke4 {5s}
(51... Kc4 {27s} 52. Bb6 {1s}) (51... Kc6 {1:10m} 52. Kg5
{4s}) 52. Bb6 {8s} Kf4 {8s} 53. Bc7 {6s} Ke5 {13s} 54. Kg4
{3s} Ke6 {7s} 55. Bb8 {11s} Kd7 {9s} 56. Ba7 {1s})
(50... Ke6 {43s} 51. Be3 {3s}) 51. Kg4 {3.44/14 11.51s} d5
{10.93s} (51... Ke6 52. Be3 {5s} Ke5 {5s} 53. Kf3 {6s} Kd5
{7s} (53... d5 {14s} 54. Bf2 {12s} Ke6 {13s} 55. Kf4 {5s})
54. Ba7 {17s} Kc4 {8s} (54... Ke5 {16s} 55. Ke3 {2s} Kd5
{10s} 56. Kd3 {0s} Ke5 {6s} 57. Kc4 {1s} d5+ {10s} 58. Kb5
{1s}) (54... Kc6 {51s} 55. Ke4 {6s}) 55. Ke4 {4s} Kb5 {10s}
56. Bb6 {3s} Kc6 {8s} 57. a4 {0s} Kd7 {5s} 58. Kd5 {1s})
(51... Ke5 {50s} 52. Kf3 {8s} Kd5 {6s} (52... d5 {10s}
53. Ke3 {1s} d4+ {16s} (53... Kd6 {17s} 54. Kd3 {19s} Kc7
{3s} 55. Bf4+ {1s} Kc6 {5s} 56. Be3 {4s} Kc7 {2s} 57. Ba7
{3s}) 54. Kd3 {1s} Kd6 {10s} 55. a4 {1s} Kc7 {6s}
(55... Kc6 {55s} 56. Kxd4 {1s}) (55... Kc5 {28s} 56. Bf4
{9s}) 56. Bf4+ {6s} Kc6 {7s} 57. Kc4 {9s} d3 {1s} 58. Kb4
{7s} Kd7 {11s} 59. Kc3 {7s}) (52... Kd4 {14s} 53. Be3+
{2s}) 53. Be3 {9s}) 52. Bc3+ {4.22/14 10.72s} Ke6 {12.39s}
(52... Ke7 {53s} 53. Bd4 {10s} Kd8 {25s} 54. Kf5 {4s})
53. Bd4 {4.27/13 11.19s} Kd7 {11.30s} (53... Ke7 54. Kf5
{4s}) 54. Kf5 {4.54/13 9.45s} Kc6 {35.37s} (54... Kd8
{1:29m} 55. Ke5 {8s} Kc7 {8s} 56. Ba7 {2s}) (54... Kc7
{41s} 55. Ba7 {5s} Kc6 {28s} 56. Ke5 {17s}) 55. a4 {4.64/12
11.12s} (55. Ke5 {19s} Kc7 {45s} 56. Ba7 {4s}) 55... Kd7
{9.43s} (55... Kd6) (55... Kc7 {1:29m} 56. Ba7 {3s} Kd6
{18s} 57. Bb6 {1s}) 56. Ke5 {6.44/13 5.83s} Kc7 {10.52s}
57. Ba7 {4s} (57. Kxd5 $4 {3s} Kb8 $11 {2s}) 1-0
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