Author: Peter McKenzie
Date: 18:37:53 09/18/01
Go up one level in this thread
On September 18, 2001 at 18:26:00, Uri Blass wrote: >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 Do any programs go for Rxb2 here? How about Rebel? Perhaps better to put the f4 pawn onto f2 to make an immediate Nc4 less strong. Peter
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