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Subject: Re: The best "death-save" I ever saw

Author: Robert Hyatt

Date: 06:41:16 03/02/00

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On March 02, 2000 at 09:09:48, stuart taylor wrote:

>Obviously a bug in stalemate evaluation    S. Taylor


There is _no_ stalemate evaluation to have a bug.  This is found by the
tree search, where there are no legal moves and the side on move is not in
check...

The problem is that the rook checks will never end, and once the engine sees
that, a draw by repetition, or by the 50 move rule, or by stalemate, all look
_exactly_ the same.  Kx was the quickest/easiest way to end the game.

This is rare, but happens.  I have (so far this past week or so) seen this
happen to crafty playing Chess Tiger, where crafty was 3 pawns up but avoided
trading rooks and ended up in this trap.  And on another occasion it returned
the favor by doing the same thing to Tiger.  It is a depth of search issue,
and not evaluation.  You just have to see deep enough to realize that the
checks never end, and then avoid stepping into that position, rather than
stepping into it and then finding out (later) that the checks never end.



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