Author: fca
Date: 13:17:51 08/16/98
Go up one level in this thread
On August 16, 1998 at 10:06:53, Don Dailey wrote:
>On August 15, 1998 at 22:18:24, Jeff Anderson wrote:
>
>>Can someone perhaps give me a rundown of the piece values used by different
>>chess programs? How do small changes piece values in programs affect their
>>play?
>>Thanks,
>>Jeff
>Here are some values Larry Kaufman recommended that he felt would make
>most decisions reasonably correct. It is based on 1/3 pawn units,
>which he felt was the lowest unit that can return good values. He
>also considered finer resolution like 1/4 units but thinks the 1/3
>unit is the best if you want the unit size to be relatively grainy:
>pawn 3
>knight 3
>bishop 10
>rook 15
>queen 29
>Bish Pair 1
Try 9 for knight instead, Jeff, else expect some heavy losses for your program
:-))
Read all of what I state with the caveat that of course values cannot be
ascribed to pieces in general terms, it depends on the whole position, so we are
only talking crude averages over {whole game} etc.
An interesting effect of the above is assuming both sides had a bishop pair to
start off with, the "close exchange" of B + N v R + P would cost
10 + 9 + 1 (loss of B-pair) v 15 + 3
i.e. 20 v 18
i.e. 2/3 of a pawn down for the loser of B+N. I think this is wrong, and should
be 1/3 pawn. If we up R to 16 it also produces a more reasonable result v Q, as
(ignoring 2 rooks in case there is a 2-R bonus)
R + B + P v Q
with my amendment gives
16 + 10 + 3 v 29
i.e. 29 v 29
i.e. fits in with my OTB observation that R+B+P v Q often holds...
Kind regards
fca
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