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Subject: Re: Razoring? (Clarification)

Author: Ernst A. Heinz

Date: 02:07:06 01/29/99

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On January 28, 1999 at 17:28:49, Peter Fendrich wrote:
>
>The idea isn't that new!
>Chess 4.5 used what you are describing as early as 1974!
>They never called it razoring or anything else from what I know.
>Source: "Chess skill in man and machine", Peter W. Frey, 1977.

Dear Peter,

Thank you very much for pointing us to Slate & Atkin again -- I have to admit
that I completely forgot about this short passage in their article which
actually starts on page 107 in the 2nd edition of Frey's classic book.

There, Slate & Atkin introduce a limited form of normal futility pruning at
frontier nodes with a remaining depth of 1 ply (called "n-1" by them). They
do no depth reduction but really cut all quiet moves if the position is futile
with respect to "material balance + maximal positional score <= alpha". In
contrast to Jonathan's normal futility pruning they do not prune any captures.

=Ernst=



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