Author: Uri Blass
Date: 16:49:34 11/09/02
Go up one level in this thread
On November 09, 2002 at 19:26:43, Uri Blass wrote: >On November 09, 2002 at 18:40:44, Uri Blass wrote: > >>On November 09, 2002 at 18:13:35, Ricardo Gibert wrote: >> >>>Are there any chess engines that understand anything about strategic exchange >>>sacs? >>> >>> >>>The following is an instructive example of an exchange sac that yields a >>>strategicly won position: >>> >>>[D]r3r1k1/1pqn1pbp/p2p2p1/3P4/1RP5/4B3/P3BPPP/3Q1RK1 b - - >>> >>>From Polugaevsky-Petrosian 50th USSR Ch Final 1958 >>> >>>19...Rxe3!! 20.fxe3 Nc5-+ 21.Qc2 Re8 22.Rf3 Bh6 23.Qc3 Qe7 24.Rb6? Na4 0-1 >>> >>>Neither Nimzo8 nor Ruffian 1.0.1 have a clue in the above position. >> >>Movei can see only a small positional compensation for white(score 1.30 at depth >>11 and 1.20 at depth 12 after 19...Rxe3 20.fxe3 Nc5 when the material advantage >>is considered as slightly more than 1.30) >> >>Maybe with bigger positional scores it can find it. >> >>depth=11 +1.30 f1f3 c7a5 d1b1 a8e8 b4b6 a5d2 g1f2 f7f5 f2f1 g7e5 g2g3 >>Nodes: 24362368 NPS: 116907 >>Time: 00:03:28.39 >> >>depth=11 +1.30 f1f3 c7a5 d1b1 a8e8 b4b6 a5d2 g1f2 f7f5 f2f1 g7e5 g2g3 >>Nodes: 39418809 NPS: 118563 >>Time: 00:05:32.47 >> >>depth=12 +1.20 f1f3 c7a5 d1b1 a8e8 g1h1 g7h6 b4b6 h6e3 b6d6 a5d2 b1f1 f7f5 >>Nodes: 41103072 NPS: 118613 >>Time: 00:05:46.53 >> >>Can you win Ruffian or Nimzo with black from the above position? >> >>Uri > >Update. > >I looked at the analysis of movei and it seems that Rf3 failed low for some >reason(or maybe movei changed it's mind to Rb1 and Rb1 failed low. > > >Here are the last lines: >depth=13 +0.60 b4b1 c7a5 d1c2 a8e8 g1h1 e8e3 e2d1 g7d4 d1g4 f7f5 b1d1 e3e4 g4e2 >Nodes: 341408921 NPS: 120078 >Time: 00:47:23.22 > >depth=13 +0.61 d1e1 >Nodes: 370167686 NPS: 120674 >Time: 00:51:07.48 > >Qe1 failed high > >Uri It was a wrong fail high a right fail high was for Qc1 depth=13 +0.74 d1c1 c7e7 f1f3 a8e8 f3h3 f7f5 b4b6 f5f4 h3f3 f4e3 f3f4 g7e5 f4f1 Nodes: 501475681 NPS: 121106 Time: 01:09:00.78 depth=14 +0.84 d1c1 c7e7 f1f3 a8e8 f3h3 e7g5 b4b1 g7h6 g1h1 e8e3 c1e3 g5e3 h3e3 h6e3 Nodes: 542864694 NPS: 121580 Time: 01:14:25.06 Uri
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