Computer Chess Club Archives




Subject: Re: Finding mate in the quiesce search

Author: Steve Maughan

Date: 08:28:23 08/24/04

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>If I evaluate a position using the quiescence search and that returns "mate in
>5", how can I be sure that it's really a mate in 5 if the quiescence search
>hasn't explored all the possible moves?

A couple of point:

1.  In the QSearch, if you're in check you should explore *ALL* moves that get
out of check

2. In the QSearch, if you're not in check you should have the option of standing
pat i.e. returning the score for the current position.

So if you find a mate that is not forced (i.e. [INITIAL POSITION GOING INTO
QSearch] BxR, QxB mate), then assuming that the Initial Position is not a check,
the score that is returned after BxR will be -Checkmate which isn't higher than
the current score, so the Initial Positions static score will be returned from
the QSearch.

Alternatively, if you are in check in the QSearch and *ALL* moves out of check
return a -Checkmate score then the QSearch must also return -Checkmate.

I hope this helps,


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