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Subject: Re: Erm... dodgy EPD tests

Author: Robert Hyatt

Date: 11:02:05 04/29/00

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On April 29, 2000 at 13:54:10, Colin Frayn wrote:

>OK folks,
>
>Here are two positions taken from a 16 position pawn endgame test suite that I
>found somewhere.  ColChess disagrees with both of the best moves given here,
>giving alternative best moves both with won evaluations for many ply.  I tested
>Crafty and it agreed with ColChess for the few minutes that I left it for.
>
>Am I (and both programs) missing something clever, or are the best moves that
>are given here both wrong?
>
>
>----------
>Position 1
>----------
>
>[D]6k1/7p/5P1K/8/8/8/7P/8 w - -
>
>Suggested best move : Kh5
>ColChess prefers : Kg5 (Spots at 20 ply that it's won)




Kg5 is the correct move  It is a mate in 18 counting that move.  Kh5 is a
draw.  The position is wrong, or the best move is wrong.


>
>----------
>Position 2
>----------
>
>[D]4k3/4Pp2/5P2/4K3/8/8/8/8 w - -
>
>Suggested best move : Kf4
>ColChess prefers : Kf5 (gives mate in 14 after 3 minutes' thinking, and at depth
>of 22 ply)
>

This one is ok.  Kf5 is a mate in 13.  Kf4 is also a mate in 13.



>Seems to me here that the black king is stuck to squares d7 and e8 and whatever
>white does (within reason) it can't really go wrong.
>
>I'd kinda like to know if there's a bug in my evaluation function so that I can
>fix it, but I hope that there isn't.....
>
>Cheers,
>Colin



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