Author: Robert Hyatt
Date: 21:48:55 04/12/03
Go up one level in this thread
On April 12, 2003 at 04:22:57, Uri Blass wrote: >On April 12, 2003 at 01:44:26, Robert Hyatt wrote: > >>On April 11, 2003 at 12:24:43, Uri Blass wrote: >> >>>On April 11, 2003 at 12:06:31, Robert Hyatt wrote: >>> >>>>Here is a position from a game Crafty played on ICC today. >>>> >>>>[d]8/8/1p4k1/3K1p1p/1R3P1P/6P1/3r4/8 w - - >>>> >>>>This was showing as a draw until white uncorked the Rd4 interposition to block >>>>the check. At this point, black's Rxd4 starts to climb as it should. The score >>>>goes to >>>>-10 quickly. >>>> >>>>This seems to be an example of an engine that misses the power of the "distant >>>>passed >>>>pawn". I won't name names to protect the guilty, but it shows that certain >>>>pieces of >>>>knowledge are key to prevent a draw from becoming a loss. >>> >>>There is some stage when the passed pawn is trapped and if the program >>>can see it and stop there to evaluate then it may evaluate it wrong. >>> >>>I suspect that the problem is in evaluating a pawn endgame >>>with no passed pawns. >>> >>>If you search deep but not deep enough you can see that b6 is gone >>>so to solve it by evaluation you need evaluation >>>of pawns relative to the kings to understand that black is losing inspite of the >>>fact that black is a pawn up. >>> >>>Uri >> >> >>That has to be part of the evaluation. IE you have to know that you can >>give the pawn up if your king is closer to the remaining pawns than the >>opposing king is... >> >>I do that obviously... > >This has nothing to do with the pawn. Yes it does. _first_ you need to know that the distant passer is a winning advantage. _then_ you have to understand that if your king is closer to the remaining pawns then even if the passer disappears you _still_ are winning. Without _both_ you can't play these right because trying to hold on to the distant passer draws. > >You have to evaluate correctly the following position that can happen >if you do not search deep enough > >[D]8/8/1K6/5p1p/4kP1P/6P1/8/8 w - - 0 6 > >I hope that movei will be able to see it after I add some knolwedge but the >knowledge that is needed is not about passed pawns because there are no passed >pawns in that position. > >Uri >Uri That's exactly what I said... But at shallow depths you had better know about the distant passer of you will not try to reach the position you gave. Then you never get a chance to get your king closer and win.
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