endgame position

[jdart]

This position occurred in a game between Toga II 1.4.1SE and Spike 1.2 Turin, from a tournament run by Graham Banks:

[D] 4k3/1R6/3p2pp/3P1p2/5PP1/2p4P/1pK5/4b3 w - -

here Toga played 58. gxf5 and won rapidly after .. gxf5 Rh7 Bd2 Rxh6 Bxf4 Rh5 (see game below).

While this seems pretty simple, Arasan is quite blind here and persists in thinking gxf5 is good for no better than a draw. Could just be a bug, but other programs seem to have trouble with this too.

Full game below:

[Event "40 Moves in 68 min"]
[Site "Toga II 1.4.1SE Gauntlet"]
[Date "2008.06.14"]
[Round "1.7"]
[White "Toga II 1.4.1SE"]
[Black "Spike 1.2 Turin"]
[Result "1-0"]
[PlyCount "165"]
[EventDate "2008.??.??"]

1. d4 {book 0s} Nf6 {book 0s} 2. c4 {book 0s} g6 {book 0s} 3. Nf3 {book 0s} Bg7
{book 0s} 4. g3 {book 0s} O-O {book 0s} 5. Bg2 {book 0s} d6 {book 0s} 6. O-O {
book 0s} Nc6 {book 0s} 7. Nc3 {book 0s} a6 {book 0s} 8. d5 {book 0s} Na5 {
book 0s} 9. Qd3 {+0.02/17 1:43m} c5 {-0.20/15 1:57m} 10. e4 {-0.13/17 2:13m}
Rb8 {-0.34/15 2:08m (Bd7)} 11. Bd2 {-0.11/17 2:04m (Rb1)} b5 {-0.66/16 1:51m}
12. b3 {-0.21/18 2:53m (cxb5)} bxc4 {-0.80/17 3:00m (Bd7)} 13. bxc4 {
-0.15/17 1:28m} Rb4 {-0.78/18 4:45m} 14. Ne2 {-0.18/18 2:01m (Nd1)} Ra4 {
-0.80/16 2:01m} 15. Rac1 {-0.41/17 1:54m (Rfc1)} Bg4 {-0.95/16 3:06m} 16. Nc3 {
-0.50/17 2:02m (Bc3)} Rxc4 {-0.96/16 2:04m} 17. h3 {-0.53/17 2:22m (Rb1)} Bxf3
{-1.05/15 2:24m} 18. Qxf3 {-0.59/17 2:07m} Rd4 {-0.78/17 4:31m (Nd7)} 19. Qe2 {
-0.46/18 2:06m} Nc4 {-0.58/16 6:02m} 20. Be1 {-0.31/17 1:35m} Ne5 {
-0.62/16 1:58m} 21. Rc2 {-0.44/17 2:03m (Rb1)} Qa5 {-0.79/15 1:28m (Nd3)} 22.
Nd1 {-0.13/19 1:22m} Qb5 {-1.09/17 1:23m} 23. Nb2 {-0.83/20 4:17m} Nd3 {
-0.88/17 1:28m} 24. Bc3 {-0.81/20 2:11m} Nb4 {-0.94/17 1:18m} 25. Qxb5 {
-0.67/20 2:04m (Bxd4)} axb5 {-1.30/18 1:38m} 26. Re2 {-0.60/21 1:59m} Nh5 {
-1.41/17 1:51m} 27. Rb1 {-0.72/20 1:59m} Ra8 {-1.57/18 3:25m} 28. Bxd4 {
-0.85/19 1:27m} Bxd4 {-1.61/18 1:57m} 29. Nd1 {-0.88/19 1:17m} Ra5 {
-1.62/17 1:26m} 30. Rd2 {-1.00/19 2:45m (Bf3)} Nxa2 {-1.60/17 1:30m} 31. Bf1 {
-0.95/20 1:51m} b4 {-1.76/17 1:20m} 32. Kg2 {-1.13/21 3:44m} Nc3 {
-1.77/17 1:14m (Nf6)} 33. Nxc3 {-1.16/18 24s} Bxc3 {-1.89/18 1:35m} 34. Rc2 {
-1.26/20 1:22m} Nf6 {-1.83/17 1:39m} 35. Kf3 {-1.40/20 3:13m (Bd3)} e6 {
-1.97/16 1:18m (Nd7)} 36. Bc4 {-0.92/19 1:32m} exd5 {-1.98/17 1:18m} 37. exd5 {
-1.08/20 1:23m} Nd7 {-1.91/17 1:05m} 38. Ke2 {-1.28/20 1:44m} Ne5 {
-1.99/17 1:01m} 39. Ba2 {-1.06/21 3:03m} f5 {-1.96/17 1:22m} 40. f4 {
-1.21/22 2:53m (Bb3)} Nd7 {-1.91/17 52s} 41. Bc4 {-1.22/21 1:26m} Nf6 {
-1.88/18 1:52m} 42. Ra2 {-1.16/22 1:35m} Rxa2+ {-2.25/19 1:53m} 43. Bxa2 {
-1.14/22 48s} Bd4 {-2.22/19 1:35m} 44. Rd1 {-1.12/22 2:02m (Kf3)} Ne4 {
-2.24/19 1:33m} 45. Kf3 {-1.14/22 1:26m} Nc3 {-2.12/19 2:23m (Bc3)} 46. Ra1 {
-0.79/19 1:16m} Nxa2 {-1.76/17 1:26m (Nb5)} 47. Rxa2 {-0.64/19 29s} b3 {
-1.50/17 2:04m} 48. Ra8+ {-0.70/22 1:16m} Kf7 {-1.44/18 2:27m (Kg7)} 49. Ke2 {
-0.64/23 1:50m (Rb8)} b2 {-1.39/17 1:43m (c4)} 50. Rb8 {-0.30/22 1:12m (Ra7+)}
c4 {-1.19/18 2:03m (g5)} 51. Kd2 {-0.27/23 1:10m} c3+ {-1.08/19 1:56m} 52. Kc2
{-0.24/24 1:11m} h6 {-1.08/20 2:22m (h5)} 53. Rb4 {-0.14/23 1:43m (Rb7+)} Bf2 {
-1.13/19 2:43m (Bf6)} 54. g4 {0.00/23 1:37m (Rb7+)} Kf6 {-1.05/18 2:16m (fxg4)}
55. Rb8 {0.00/23 1:13m (Rb7)} Be1 {-0.48/19 8:10m (fxg4)} 56. Rb6 {
0.00/23 1:48m} Ke7 {-0.39/18 1:17m} 57. Rb7+ {0.00/24 1:50m} Ke8 {
-0.23/19 1:16m} 58. gxf5 {+0.11/24 2:14m (Rb8+)} gxf5 {-0.44/21 1:18m} 59. Rh7
{+0.54/26 1:26m} Bd2 {-0.19/22 1:18m (Bg3)} 60. Rxh6 {+0.70/21 1:50m} Bxf4 {
0.00/22 1:37m} 61. Rh5 {+1.55/26 1:42m (Rf6)} Ke7 {+0.51/23 2:54m} 62. Rxf5 {
+1.65/26 1:18m} Be5 {+1.56/23 3:03m} 63. h4 {+1.93/27 1:54m} Bf6 {
+1.81/22 1:38m} 64. h5 {+2.06/28 1:52m} Kf7 {+1.81/21 1:52m} 65. Rf3 {
+2.07/28 1:48m} Kg7 {+2.08/21 57s} 66. Re3 {+2.07/27 1:56m} Bd4 {+2.18/21 1:13m
} 67. Re4 {+2.09/26 1:47m} Bf2 {+2.35/20 48s} 68. Re7+ {+2.18/24 1:22m (Rc4)}
Kh8 {+2.55/21 1:29m} 69. Re6 {+2.18/26 1:45m} Bc5 {+2.49/22 1:04m} 70. Re1 {
+2.19/26 1:37m (Re4)} Bb6 {+2.45/22 1:19m} 71. Rf1 {+2.29/25 2:38m} Bd4 {
+2.69/22 56s} 72. Rd1 {+2.30/24 2:03m} Be5 {+2.73/22 50s (Bg7)} 73. Re1 {
+2.33/22 2:04m} Bd4 {+2.84/21 1:15m} 74. Re4 {+2.34/20 2:04m} Bg1 {
+3.37/21 1:25m} 75. Rb4 {+2.56/21 1:22m} Bf2 {+3.67/21 43s (Kh7)} 76. Rc4 {
+3.43/20 2:27m} Kg7 {+3.69/21 59s (Kh7)} 77. Rc6 {+3.42/18 2:14m} Bg3 {
+3.95/20 47s} 78. Rxc3 {+4.16/25 1:44m} Bf2 {+3.96/21 47s} 79. Rh3 {
+4.58/25 1:48m (Kxb2)} b1=Q+ {+4.29/20 47s (Bd4)} 80. Kxb1 {+6.00/27 46s} Kh6 {
+4.93/22 47s} 81. Kb2 {+6.28/29 1:27m (Kc2)} Bc5 {+5.54/23 12:19m (Bd4+)} 82.
Kc3 {+6.94/27 2:11m (Kc2)} Bb6 {+6.24/19 2:29m} 83. Rf3 {+24.57/25 4:24m} 1-0