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Subject: Re: Testposition (easy perpetual check)

Author: Robert Hyatt

Date: 10:33:01 07/06/99

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On July 04, 1999 at 06:19:17, Frank Schneider wrote:

>On July 03, 1999 at 19:16:59, Gerrit Reubold wrote:
>
>>Hi all,
>>
>>please test your programs with the following position
>>
>>5rk1/1r3pp1/pp2pq2/3p4/3Q4/1PR5/P4PPP/4R1K1 w - -
>>
>>it is from a game which my program (Bringer) lost with white against The Crazy
>>Bishop. The draw is very easy to see (for humans): Qxf6 gxf6, and then rook
>>checks at h3, g3, f3... How long does your program take to find Qxf6 *with a
>>draw score*. How many plies / seconds? Question to the programmers: What do you
>>do to solve such positions fast? Extending on checks is not enough, my program
>>needs a 12 ply search (8 minutes on a PII-300) to find the draw (Qxf6 is found
>>earlier).
>Gromit shows a drawscore after iteration 5 (1sec).
>
>Frank
>>
>>Greetings,
>>Gerrit Reubold


This is an evaluation issue.  If your program thinks white is better, then it
will see a draw.  If your program likes black, then it will find that black
doesn't _have_ to take the draw as the repetition is certainly not forced if
black or white doesn't want to repeat.

King safety might be over-emphasized in any program that sees draw, because
with two rooks, black's king is not getting mated any time soon...  and it
becomes a matter of can black hold the extra pawn, untangle the rooks, and
then make white choke on that extra pawn?

Whether Qxf6 is the best move is another question, of course.  I tried several
alternatives that seemed playable...  Crafty would play Qxf6 from iteration 1
on, although as white I would personally try to avoid trading queens unless I
thought black could quickly take the h-file and turn it into a weapon...



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