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Subject: Re: Unusual Crafty behavior ?!

Author: James T. Walker

Date: 11:29:55 11/18/01

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On November 18, 2001 at 12:58:51, Jesper Antonsson wrote:

>On November 18, 2001 at 12:09:10, Jeff Lischer wrote:
>
>>On November 18, 2001 at 10:03:15, piet de hoop wrote:
>>
>>>The next position occured in Diep versus Rebel Century 4 round 6 of the Dutch
>>>Open Computer Chess 2001
>>>
>>>[D] 8/6p1/3k3p/8/3K4/7P/8/8 b - - 0 43
>>>
>>>The result was a draw, but for some computerprograms I tried, the evaluation was
>>>from -1 to -3.4 pawn. (Fritz 6.0, Crafty,Yace)
>>>
>>>I expect that programs equipped with the right pawntable base have no problem
>>>with this position, but i expected that programs without these tablebase while
>>>calculating over 30 plys or more should give the right evalution?
>>>
>>>Or do i miss something?
>>>
>>>Piet
>>
>>When I tried this position with programs using all 3,4, and 5 piece tablebases
>>they saw the draw immediately.
>>
>>The only oddity was Crafty. I was using Crafty 18.12 in WinBoard 4.2.3. When
>>Crafty played White, it saw the draw in tablebases and moved immediately. When
>>it was Black, however, it did not see the draw in tablebases. Instead it anayzed
>>the position as it normally would and gave Black a 2-3 pawn advantage. Other
>>programs (Yace, Gandalf) worked fine in WinBoard as both White and Black.
>>
>>Is this the intended behavior for Crafty or a bug? If it is intended, why?
>
>I think it's intended. If you are white, you'll want to take the quickest route
>to a draw. If you are black, you would either want to take the slowest route to
>a draw or, perhaps better, search and play as usual (but only among drawn moves,
>of course) in the hope that a human opponent will make an error and enter lost
>tablebase space. :-)

If I give this position to Fritz 6 it says draw immediately with black to move.
Jim



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