Author: Jorge Pichard
Date: 11:36:49 12/04/03
Go up one level in this thread
On December 04, 2003 at 11:03:43, Uri Blass wrote: >On December 04, 2003 at 10:55:06, Jaime Benito de Valle Ruiz wrote: > >>(ALL these tests are done with 3,4 and some 5 tablebases in an Athlon 1900+ with >>512 Mb) >> >>This position was recently posted by Joachin Rang, and no one really suggested >>why is it so hard for commercial engines: >> >>[D]8/5R2/2p5/8/7P/1K2b3/P3kp2/8 w - - 0 1 Delfi WB2 27 MB: 2 00:00 -2.16 Kc4 f1=Q. Rxf1 Kxf1. 3 00:00 -2.16 Kc4 f1=Q. Rxf1 Kxf1. 4 00:00 -2.16 Kc4 f1=Q. Rxf1 Kxf1. 5 00:00 -1.99 Kc4 c5. a4 f1=Q. Rxf1 Kxf1. 6 00:00 -2.20 Kc4 f1=Q. Rxf1 Kxf1. a4 Ke2. 7 00:00 -1.98 Kc4 f1=Q. Rxf1 Kxf1. a4 Ke2. a5 8 00:00 -2.07 Kc4 f1=Q. Rxf1 Kxf1. a4 Ke2. a5 c5. 9 00:00 -1.80 Kc4 f1=Q. Rxf1 Kxf1. a4 Ke2. a5 Kf3. a6 9 00:00 -1.70 Rxf2+... 9 00:00 -1.80 Kc4 f1=Q. Rxf1 Kxf1. a4 Ke2. a5 Kf3. a6 10 00:00 -1.97 Kc4 f1=Q. Rxf1 Kxf1. a4 Kf2. a5 Kg3. h5 Kf4. 10 00:00 -1.81 Rxf2+... 10 00:00 -1.70 Rxf2+ Bxf2. Kc4 Kf3. h5 Ke4. h6 Be3. h7 Bd4. a4 Bh8. 10 00:00 -1.60 h5... 10 00:00 -1.70 Rxf2+ Bxf2. Kc4 Kf3. h5 Ke4. h6 Be3. h7 Bd4. a4 Bh8. 11 00:00 -1.48 Rxf2+ Bxf2. Kc4 Kf3. h5 Ke4. h6 Be3. h7 Bd4. a4 Bh8. a5 12 00:01 -1.44 Rxf2+ Bxf2. Kc4 Kf3. h5 Ke4. h6 Be3. h7 Bd4. a4 Bh8. a5 Kf5. 12 00:01 -1.34 h5... 12 00:02 -0.26 h5! f1=Q. Rxf1 Kxf1. Kc4 Ke2. h6 Bxh6. Kc5 Kf3. Kxc6 Ke4. 12 00:02 -0.16 Kc4...! 12 00:02 -0.26 h5! f1=Q. Rxf1 Kxf1. Kc4 Ke2. h6 Bxh6. Kc5 Kf3. Kxc6 Ke4. 13 00:03 -0.15 h5 f1=Q. Rxf1 Kxf1. Kc4 Ke2. h6 Bxh6. Kc5 Be3+. Kxc6 Kd3. a4 Kd4. 14 00:04 -0.16 h5 f1=Q. Rxf1 Kxf1. Kc4 Ke2. h6 Bxh6. Kc5 Kd3. Kxc6 Bf4. a4 Kd4. 15 00:19 0.38 h5! f1=Q. Rxf1 Kxf1. a4 Bd2. Kc4 Ke2. Kc5 Kd3. Kxc6 Kc4. a5 Bxa5. h6 16 00:43 0.63 h5 f1=Q. Rxf1 Kxf1. a4 Bd2. Kc4 Ke2. a5 Bxa5. h6 Bc7. Kc5 Kd3. h7 Be5. Kxc6 17 01:01 0.49 h5 f1=Q. Rxf1 Kxf1. a4 Bd2. Kc4 Ke2. a5 Bxa5. h6 Bc7. Kc5 Kd3. h7 Be5. Kxc6 Bh8. 18 01:53 0.53 h5 f1=Q. Rxf1 Kxf1. a4 Bd2. Kc4 Ke2. a5 Bxa5. h6 Bc7. Kc5 Kd3. h7 Be5. Kxc6 Kd4. Kd7 Delfi >> >>My guess is that some engines' evaluation are not "aware" of the danger of two >>passed pawns being stopped just by a bishop, and because of pruning and/or >>Null-move, they need to reach a great depth to find the move. >> >>For example, in this position (4 plies after the initial one)... >> >>[d]8/8/2p5/8/7P/4b3/P1K5/5k2 w - - 0 3 >> >>Shredder 7 needs a depth of 17 to give it a positive score (over +4.00), and >>realize it's winning. >>Fritz 8 needs only 14 to come up with a positive score(+0.44), but it takes >>longer than for Shredder. Later, at depth 17 the score is a convincing +5.75. >>Junior 8 needs to reach depth 21 (fast, though). >> >>[D]8/6p1/P1b1pp2/2p1p3/1k4P1/3PP3/1PK5/5B2 w - - >> >>In this other position, the problem appears to be the same: After several plies >>we have: >> >>[d]8/P5p1/8/2p1p3/1k1P4/4p3/1PK3b1/8 w - - 0 6 Delfi WB2 27 MB: 2 00:00 0.83 a7 Ba8. 3 00:00 0.89 a7 Ba8. Be2 4 00:00 0.83 a7 Ba8. Be2 g5. 5 00:00 0.79 a7 Ba8. Kd2 Kb3. Kc1 6 00:00 0.53 a7 Kb5. d4+ Kb6. dxc5+ Kxa7. Bc4 Bd5. 7 00:00 0.68 a7 e4. Kd2 exd3. Bxd3 c4. Bg6 8 00:00 0.57 a7 e4. b3 Bd5. dxe4 Bxe4+. Bd3 Ba8. e4 9 00:00 0.55 a7 e4. dxe4 Bxe4+. Bd3 Ba8. b3 e5. Bf5 Kb5. 10 00:01 0.62 a7 e4. dxe4 Bxe4+. Bd3 Ba8. b3 e5. Bc4 Be4+. Kd2 Ba8. 11 00:01 0.28 a7 e4. dxe4 Ka5. Bc4 Kb6. e5 fxe5. Kd3 g5. Bxe6 Kxa7. 12 00:02 0.11 a7 e4. dxe4 Bxe4+. Bd3 Ba8. Kd2 Ka5. Bc4 Kb6. Bxe6 Kxa7. Kd3 13 00:05 0.03 a7 e4. d4 cxd4. exd4 Ka5. Bc4 Kb6. Bxe6 Kxa7. d5 Ba4+. b3 Bb5. 14 00:08 0.00 a7 e4. dxe4 Bxe4+. Bd3 Ba8. Bg6 Ka5. Kd3 Kb6. Bf7 Kxa7. Bxe6 Kb6. Kc4 15 00:17 -0.12 a7 e4. dxe4 Bxe4+. Bd3 Ba8. Bg6 Ka5. Kd3 Kb6. Bf7 Kxa7. Bxe6 Kb6. Kc4 Be4. 16 00:28 -0.10 a7 e4. dxe4 Bxe4+. Bd3 Ba8. Bg6 Ka5. Kd3 Kb6. Bf7 Kxa7. Bxe6 Kb6. Kc4 Be4. Bd5 17 00:51 -0.16 a7 e4. dxe4 Bxe4+. Bd3 Ba8. Bg6 Ka5. Kd3 Kb6. Bf7 Kxa7. Bxe6 Kb6. Kc4 Bf3. Bd7 g6. 18 01:36 -0.14 a7 e4. dxe4 Bxe4+. Bd3 Ba8. Bg6 Ka5. Kd3 Kb6. Bf7 Kxa7. Bxe6 Kb6. Kc4 Bf3. Bd7 g6. Be6 18 03:10 -0.04 Bg2... 18 04:06 2.65 Bg2! Bxg2. e4 c4. a7 cxd3+. Kxd3 f5. a8=Q Bxe4+. Qxe4+ fxe4+. Kxe4 Kb3. g5 Kc4. Kxe5 g6. Kxe6 Kd3. Kf7 Ke4. Kxg6 Delfi >> >>Both Fritz and Shredder need depth 12 from here to give a positive score! Any >>(bad) player would realize almost instantly that white are winning here! >> >>Does it make sense what I'm saying? >> >>Regards, >> >> Jaime > >Of course > >programs are basically stupid in detecting unstopable passed pawns. > >The practical importance of this problem was simply not big enough for the >commercial programmers to care about fixing the problem until today. > >Uri
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