Author: Uri Blass
Date: 08:16:24 04/08/03
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On April 08, 2003 at 10:57:21, Richard Pijl wrote: >On April 08, 2003 at 10:04:02, Uri Blass wrote: > >>[D]8/5pp1/4p1kp/1Q6/2rqP2P/8/5PP1/5RK1 w - - 0 27 >> >>This position happened in a game of movei. >>For the game see http://f11.parsimony.net/forum16635/messages/46511.htm >> >>I found that latest movei also suffers from the same evaluation problem. >> >>Movei evaluates the position as almost equal. >> >>I found that Crafty and a lot of programs understand that black has a clear >>advantage(more than 0.5 pawns for black from the >>first iterations). >> >>I understand that black is better but the question is what factor in evaluation >>helps a lot of programs to understand it. >> >>I can explain reasons to give advantage for black from program point of view: >> >>1)The black king is more advanced and it is known that the king should >>be at the last rank except endgames. > >I don't agree. After h5+ the black king is locked out from the immediate action >and has to retreat to h7. I understand it but piece square table gives h7 worse score than g1 for the king except endgames. I did not ask for opinion of humans but how do programs know it. > >>2)The white pawns are more advanced so by piece square table they >>get bigger bonus after a move like h5+. > >But that would increase the white score? Yes Piece square table give bigger score for the side that it's pawns are more advanced. > >I think you can detect black's advantage with three eval terms: >- Limited mobility of the white rook. It cannot leave square f1 because of >immediate threats on f2. I understand it but the question is if program understand it. Moei use number of moves to evaluate mobility and f1 is only slightly worse than possible sqares of the black rook. >- Black has two attacking pieces, White only one. Movei does not count attackers and I do not know if this is an important factor. I think that the important factor is weaknesses of the white pawns. Here is another position when I think that black has no advantage inspite of Crafty's opinion. [D]8/5pp1/6kp/1Q6/2rq4/7P/5PP1/5RK1 b - - 0 1 Uri Uri >- Black has easy access to the 2nd row, increasing pressure on the white king >position. > >Richard.
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