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Subject: Re: Static Exchange Evaluation (SEE) for pruning in quiescence (?)

Author: Uri Blass

Date: 05:07:07 08/19/03

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On August 19, 2003 at 08:05:39, Uri Blass wrote:

>On August 19, 2003 at 07:43:08, Bo Persson wrote:
>
>>On August 19, 2003 at 06:19:59, Joost Buijs wrote:
>>
>>>
>>>To me it looks wrong to skip losing captures from the quiescence search if the
>>>losing captures are determined by a SEE that is wrong in some cases, e.g. pinned
>>>pieces. If you use the SEE for move ordering purposes only this problem doesn't
>>>exist.
>>
>>But it is always only an approximation, you just want it to be good enough to
>>avoid flat out blunders.
>>
>>In a position like this
>>
>>[D]8/1p6/r1r5/8/8/8/8/R1R5 w - - 0 1
>>
>>SEE will believe that the black rooks are both defended, but they are not. This
>>is not a "pin", but an "overload" which is still missed. You just can't get it
>>all (cheap).
>>
>>
>>Bo Persson
>
>They are defended.
>
>Rxa6 Rxa6
>
>if you want a better example then it is better to put a pawn at b6 and not only
>at b7.
>
>Uri

It is still wrong because Rxa6 Rxc1

It is better to put 2 knights and not 2 rooks to show that SEE may miss a good
capture by white.

Uri



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