Author: Uri Blass
Date: 15:26:00 09/18/01
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On September 18, 2001 at 18:10:19, Robert Hyatt wrote: >On September 18, 2001 at 18:08:32, Robert Hyatt wrote: > >>On September 18, 2001 at 17:17:35, Uri Blass wrote: >> >>>On September 18, 2001 at 16:33:08, Robert Hyatt wrote: >>> >>>>On September 18, 2001 at 13:24:45, Uri Blass wrote: >>>> >>>>> >>>>>Note that I said that computers can safely evaluate +2 if they do not see a >>>>>positional advantage for the side with less pawns. >>>>> >>>>>Having a distant majority is a positional advantage. >>>> >>>>Not when hardly _any_ programs recognize it. >>>> >>>> >>>>> >>>>>I also think that Ed is right and today search solves usually the problem of >>>>>missevaluating pawn majority. >>>> >>>>I disagree. If you enter into a series of captures, you might burn all your >>>>search on the captures and have none left to see what the majority is going to >>>>do. So you take the first step, and then you are committed. And every move >>>>you make sees your score drop as you begin to sense the problem. By the time >>>>the forced trades are done, you realize you are lost, as a king and pawns ending >>>>can be searched incredibly deeply. >>> >>>Can you give a position that demonstates your point? >>> >>>Uri >> >> >>Here is a simple attempt: >> >>[D]2k5/1r6/3p1p2/n2p1p2/P2PpP2/R3P3/1BK5/8 b - - >> >>Here black has several moves to try, one which liquidates into a pawn up >>(but dead lost) ending. Rxb2 Kxb2 Nc4+ Ka2 Nxa3 Kxa3 and white is a pawn >>down, but winning easily. >> >>Once you start with Rxb2, you are committed. As if you try to back out and >>not play Nc4 and Nxa3, you are an exchange down. And if you do recover the >>material, you are dead lost. Add another such forced capture/recapture and >>you have burned 6 plies. You won't see white winning all the black pawns >>and winning. > > >Note that I don't say there are not better moves for black here. The point >was to show a move choice that commits you to a course of action that gets >worse and worse as you go deeper and deeper. I think that this is not a good example because white has an obvious positional advantage for programs(white has a passed pawn when black has 2 pawns on the same file for file d,f Uri
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