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Subject: Re: Endgame trap; some progs see it - How is it found? e.g. Crafty?

Author: Paul Richards

Date: 16:04:24 05/27/99

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On May 26, 1999 at 23:24:02, Robert Hyatt wrote:

>OK.. I read the whole thread, and tried it.  It is the piece of knowledge
>that says K + B + RP on wrong color draws if the opposing king can get to the
>queening square before the pawn.  That is why Crafty plays Nh6 as black and
>_never_ considers gxh6.  If you play Nh6, a 1 ply search rejects gh because it
>evaluates to DRAW.  Very simple answer after looking at it..   so forget my
>first answer.  That happens, but not in this case...

What's interesting is that a 1-ply search rejects gxh6 immediately, but
if you set Crafty to analyze for black after gxh6, it searches to 15-16 ply
before seeing that Kh8 leads to the draw.  As a matter of fact it awarded
Kh8 a !! all by itself, which I thought was a very nice touch. :)  So it
appears that it decides on the draw different ways before and after gxh6,
or that the special knowledge code is invoked at a different point?



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