Author: Roy Eassa
Date: 11:55:02 08/26/01
Go up one level in this thread
On August 26, 2001 at 14:47:51, Roy Eassa wrote: >On August 26, 2001 at 14:45:40, Roy Eassa wrote: > >>On August 26, 2001 at 14:40:33, Roy Eassa wrote: >> >>>[D] 8/2r1k2p/p3p1p1/3r1p2/8/1P3PP1/P2RK2P/3R4 b - - >>> >>>I reached this position as white recently, and after the game I used Gambit >>>Tiger 2.0 to help analyze. What occurred in the game was: >>> >>>1... Rcd7(?) 2. Rxd5 Rxd5?? 3. Rxd5 exd5 >>> >>>after which I believe white should win (which I did). I believe it's very bad >>>for black to trade off both pairs of rooks, and best to avoid allowing white to >>>exchange even one pair of rooks here because of isolating black's pawn. >>> >>>It appears that Gambit Tiger 2 on my Athlon 1.2 GHz does not really understand >>>that after move white's move 3 above, white should win. And it believes the >>>position is essentially equal after white's move 2. >>> >>>Here is its analysis after black's move 1: >>> >>>00:00:00.9 0.22 9 168541 h3 Kf6 Rxd5 exd5 Rc1 Ke6 Kd3 f4 Rc6+ Rd6 Rxd6+ Kxd6 >>>00:00:00.3 0.16 9 184134 h3 Rxd2+ Rxd2 Rxd2+ Kxd2 e5 Ke3 Ke6 g4 fxg4 fxg4 h5 a3 >>>hxg4 hxg4 >>>00:00:01.9 0.12 10 445643 h3 Rxd2+ Rxd2 Rc7 Kd1 e5 Rc2 Rxc2 Kxc2 e4 fxe4 fxe4 >>>Kc3 >>>00:00:01.4 0.16 10 710893 Rxd5 Rxd5 Rc1 Kd6 Rc8 Rc5 Rxc5 Kxc5 Kd3 Kb4 h4 Ka3 >>>00:00:02.8 0.16 11 905910 Rxd5 Rxd5 Rc1 Kd6 Rc8 Rc5 Rxc5 Kxc5 Kd3 Kd5 g4 e5 gxf5 >>>gxf5 >>>00:00:03.0 0.16 12 1519152 Rxd5 Rxd5 Rxd5 exd5 b4 Ke6 Ke3 Ke5 f4+ >>>00:00:05.5 0.16 13 2286175 Rxd5 Rxd5 Rxd5 exd5 b4 Ke6 Ke3 Ke5 f4+ Kd6 a4 Ke6 Kd4 >>>h6 b5 axb5 axb5 >>>00:00:09.6 0.18 14 3833264 Rxd5 Rxd5 Rxd5 exd5 b4 Ke6 Ke3 h6 f4 g5 a3 gxf4+ Kxf4 >>>d4 Kf3 d3 Ke3 >>>00:00:18.1 0.20 15 7566502 Rxd5 Rxd5 Rxd5 exd5 b4 Kd6 Ke3 g5 f4 gxf4+ Kxf4 d4 a3 >>>h5 Kf3 d3 Ke3 >>> >>> >>>but after 2. Rxd5, suddenly Tiger prefers black to recapture with the pawn >>>rather than the rook, and its evaluation becomes worse for black. >>> >>>Non-Gambit Tiger behaves very similarly. >>> >>>Is the lack of endgame knowledge in me or the program, or is it something else? >>> >>>(Using 96MB hash; Not using table bases.) >> >> >>Junior 6 takes 41 seconds after black's move 2 to even realize that white should >>exchange the secon pair of rooks, and thinks the resulting advantage is tiny: >> >>3.Rc1 Re5+ 4.Kd3 Rd5+ >> = (0.07) Depth: 6 00:00:00 >> = (0.00) Depth: 19 00:00:35 34856kN >>3.Rxd5 exd5 4.b4 Kd6 5.a4 Kc7 6.Kd3 Kc6 7.Kd4 h6 8.b5+ >> = (0.08) Depth: 19 00:00:41 39945kN >> = (0.08) Depth: 19 00:00:41 39945kN > > >Fritz 6 doesn't exactly dazzle with its fast understanding, after black's move >2: > >3.Rxd5-- > µ (-0.72) Depth: 1/3 00:00:00 > µ (-0.72) Depth: 1/3 00:00:00 >3.f4 Ra5 4.a4 e5 > ³ (-0.56) Depth: 1/4 00:00:00 > = (-0.09) Depth: 4/8 00:00:00 >3.Rd3-- > = (-0.06) Depth: 4/9 00:00:00 1kN > ³ (-0.47) Depth: 9/18 00:00:00 154kN >3.f4! Rxd1 4.Kxd1 Kf6 5.h4 e5 6.fxe5+ Kxe5 7.Ke2 h6 > ³ (-0.44) Depth: 9/18 00:00:00 169kN > ³ (-0.34) Depth: 9/18 00:00:00 182kN >3.Rc1 Re5+ 4.Kd3 Rd5+ 5.Ke3 Re5+ 6.Kf2 Kd6 7.Rc8 Rc5 > ³ (-0.31) Depth: 9/19 00:00:00 228kN > = (0.00) Depth: 13/30 00:00:16 12674kN >3.Rxd5 exd5 4.Ke3 Kd6 5.Kd4 g5 > = (-0.12) Depth: 13/30 00:00:19 14134kN > = (0.19) Depth: 15/25 00:00:35 23503kN Shredder 5 seems best at understanding this, again after black's move 2. It chooses the right move in 11 seconds and, unlike the other engines, sees in 19 seconds that this gives a big advantage: position: 0 1 1.00 0:00 -0.41-- Rxd5 exd5 (2) 0.1 1.00 0:00 -0.61 Rxd5 exd5 (4) 0.2 1.00 0:00 -0.26++ f4 Rxd1 Kxd1 (7) 0.3 1.00 0:00 -0.06 f4 Rxd1 Kxd1 (10) 0.5 1.00 0:00 +0.13++ Rc1 (23) 1.1 1.00 0:00 +0.13 Rc1 (24) 1.2 2.00 0:00 +0.06 Rc1 e5 (70) 3.5 2.00 0:00 +0.09++ Rd3 Kd7 (136) 6.8 2.00 0:00 +0.11 Rd3 Kd6 (171) 8.5 3.00 0:00 +0.08 Rd3 Kd6 f4 (503) 25.1 3.00 0:00 +0.10++ Rc1 Kd7 f4 (677) 33.8 3.00 0:00 +0.12 Rc1 Kd6 f4 (870) 43.5 4.00 0:00 +0.03 Rc1 Kd6 Ke3 e5 (1.773) 77.0 5.00 0:00 +0.04 Rc1 Kd6 a4 a5 f4 (4.901) 113.9 6.00 0:00 +0.04 Rc1 e5 Rc7+ Rd7 Rxd7+ Kxd7 b4 Kd6 a4 (13.839) 203.5 7.01 0:00 +0.02 Rc1 Kd6 Rc8 Rc5 Rd8+ Ke7 Rd2 e5 (37.610) 293.8 7.03 0:00 +0.03++ Rd3 Kd6 b4 h5 Ra3 Re5+ (62.602) 324.3 7.03 0:00 +0.07 Rd3 g5 b4 Rxd3 Kxd3 g4 f4 Kd6 (80.322) 344.7 8.01 0:00 +0.07 Rd3 g5 b4 Rxd3 Kxd3 e5 h3 f4 gxf4 exf4 (135.625) 368.5 8.06 0:00 +0.08++ b4 Rxd1 Kxd1 g5 a4 Kd7 Kd2 e5 Ke3 g4 (199.705) 389.2 8.06 0:00 +0.11 b4 Re5+ Kd2 Rd5+ Kc2 h6 a4 Kf6 f4 Rxd1 Kxd1 (232.008) 391.2 9.01 0:00 -0.03 b4 Rxd1 Kxd1 Kd6 Kd2 Kd5 h3 e5 a4 e4 (364.458) 408.1 9.03 0:01 -0.02++ Rc1 Kd6 a4 Rc5 Rd1+ Kc6 f4 e5 b4 Rd5 fxe5 Rxe5+ Kf2 Re1 (436.701) 406.9 9.03 0:01 0.00 Rc1 Kd6 a4 Rc5 Rd1+ Rd5 Rc1 Rc5 (480.930) 404.8 10.01 0:01 0.00 Rc1 Kd6 a4 Rc5 Rd1+ Rd5 Rc1 Rc5 (742.176) 409.3 11.01 0:04 0.00 Rc1 Re5+ Kd2 Rd5+ Ke3 Re5+ Kd4 Rd5+ Ke3 Re5+ (1.681.189) 410.2 12.01 0:07 0.00 Rc1 Re5+ Kd2 Rd5+ Ke3 Re5+ Kd4 Rd5+ Ke3 Re5+ (3.000.681) 410.0 12.06 0:11 +0.01++ Rxd5 exd5 f4 Kd6 b4 g5 fxg5 h6 gxh6 d4 a3 (4.813.375) 414.8 12.06 0:12 +0.16 Rxd5 exd5 b4 Kd6 Ke3 g5 h3 Kc6 a4 h6 f4 Kd6 (5.504.279) 423.6 13.01 0:14 +0.41++ Rxd5 exd5 b4 Kd6 Ke3 g5 a4 a5 bxa5 Kd7 f4 g4 h4 gxh3 (6.324.681) 431.4 13.01 0:15 +0.50 Rxd5 exd5 b4 Kd6 a4 g5 Ke3 Kc6 Kd4 g4 fxg4 fxg4 b5+ axb5 axb5+ (6.847.727) 438.4 14.01 0:17 +0.75++ Rxd5 exd5 b4 Kd6 a4 g5 Ke3 Kc6 Kd4 Kb7 Kxd5 g4 fxg4 fxg4 b5 (7.965.133) 445.7 14.01 0:19 +1.25++ Rxd5 exd5 b4 Kd6 Kd3 g5 a4 Kc6 Kd4 h5 Ke5 Kb6 Kxf5 a5 (8.931.992) 452.9 14.01 0:20 +1.25 Rxd5 exd5 b4 Kd6 Kd3 Kc6 h3 Kd6 g4 fxg4 fxg4 h5 a3 hxg4 b5 gxh3 (9.283.532) 454.8 best move: Rd1xd5 time: 0:23.491 min n/s: 461.294 nodes: 10.832.584
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