Author: John Merlino
Date: 13:14:14 08/28/01
Go up one level in this thread
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.) CM8000, default personality on a PIII-600, is as follows: After a brief glance at 1...Rcd7, it sticks with 1...Rxd2+, and a slim advantage for Black: Time Depth Score Positions Moves 0:00 2/6 -0.06 22030 1...Rcd7 2. Rxd5 exd5 3. Ke3 Ke6 4. Kd4 0:00 3/7 -0.04 51652 1...Rcd7 2. Rxd5 exd5 3. Kd3 d4 4. Rc1 h6 0:01 3/7 -0.11 92974 1...Rxd2+ 2. Rxd2 e5 3. h3 Rc3 4. Rd5 e4 5. Re5+ Kd6 0:02 4/8 -0.07 216822 1...Rxd2+ 2. Rxd2 e5 3. Kf2 Ke6 4. h3 g5 5. a3 Rc3 0:07 5/9 -0.09 702192 1...Rxd2+ 2. Rxd2 e5 3. b4 Ke6 4. a4 Rc4 5. Rb2 h6 6. Kd3 Kd5 0:20 6/10 -0.06 2108067 1...Rxd2+ 2. Rxd2 e5 3. a4 g5 4. Rd5 Ke6 5. Ra5 Rc6 6. b4 Rc2+ 7. Kd3 1:03 7/11 -0.10 6490608 1...Rxd2+ 2. Rxd2 e5 3. a4 Rc5 4. b4 Rc4 5. Rb2 Ke6 6. Kd3 Kd5 7. h3 h5 2:42 8/12 -0.07 16332944 1...Rxd2+ 2. Rxd2 e5 3. a4 Rc5 4. b4 Rc4 5. Rb2 g5 6. Kd3 Rd4+ 7. Ke3 Ke6 8. Rb1 h5 If 1...Rcd7 2.Rxd5, then CM8000 takes back with the e-pawn, and a very slim advantage for White: Time Depth Score Positions Moves 0:00 4/7 -0.01 45928 2...exd5 3. Kd3 Kd6 4. Re1 Rb7 5. f4 Rc7 6. Kd4 0:01 5/8 -0.01 162297 2...exd5 3. Rd4 Ke6 4. Ke3 g5 5. Ra4 Rd6 6. Kd4 h5 0:05 6/9 0.01 507368 2...exd5 3. Rd4 Ke6 4. Ke3 g5 5. Ra4 Rd6 6. Kd4 h5 7. f4 0:17 7/10 0.01 1699835 2...exd5 3. Rc1 Kd6 4. Rc8 Re7+ 5. Kd3 Re6 6. Rd8+ Kc6 7. a3 Re1 8. Kd4 Rd1+ 9. Ke5 0:54 8/11 0.01 5397709 2...exd5 3. Rd4 g5 4. Ke3 Ke6 5. Ra4 Rd6 6. Kd4 h5 7. f4 g4 jm
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