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Subject: Re: wrong question!

Author: Richard Pijl

Date: 08:49:15 03/23/04

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On March 23, 2004 at 09:11:14, martin fierz wrote:

>On March 23, 2004 at 04:35:49, Tord Romstad wrote:
>
>>[D]k1r5/p5n1/1prp3p/5p2/P1PPp1pP/2P1P1P1/3KBP2/1R4B1 w - -
>>
>>This position occured in a blitz game on the ICC with Gothmog (white) against
>>Arasan.  Of course, as is immediately obvious to a human observer, white is
>>dead lost.  It's impossible to activate the bishop on g1, and white is
>>effectively a rook down.
>>
>>To my disgust, Gothmog was quite happy about its position, and showed a small
>>plus score.  And because Arasan appeared to be equally clueless about the
>>position, Gothmog even went on to win after a really ugly endgame.
>>
>>After the game, I decided to check Gothmog's static eval for the position.
>>It thinks that white has an advantage(!) of 0.24 pawns.  Of course it
>>notices the bad mobility for the bishop on g1, but it doesn't understand
>>that it will never be possible to activate the bishop without loss of
>>material.
>>
>>How do other engines evaluate this position?
>
>IMO this question is not the right question to ask. i think gothmog is rather
>good at giving up the exchange compared to other programs. it's static eval for
>this position would be quite ok if the white bishop was on c1 for example, where
>it's mobility is apparantly only very little bigger (one more square to go to).
>therefore you have to ask not only what the static eval for the position is that
>you gave, but also for the one with the bishop on c1. many engines will give
>black a clear edge here because they are (too) materialistic. they will do this
>in both positions. the really interesting question is whether any engine can
>detect the HUGE difference between having the bishop on c1 or g1...

The Baron doesn't see a big difference in static eval, the value is even
slightly worse for the bishop on c1. But after a short search it makes quite a
difference.
Current Development version

Original position static: -0.77
After short (10 ply search): -1.5

Bishop on c1 static: -0.87
After short (10 ply search): -0.9

The difference in score is purely because of mobility of the bishop (and rook,
when looking at the static eval).

Richard.



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