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Subject: Re: During Null Move search

Author: Roland Pfister

Date: 06:52:34 06/03/98

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On June 03, 1998 at 08:31:28, Robert Hyatt wrote:

>On June 03, 1998 at 02:45:34, Roland Pfister wrote:
>>So do I. I just don't allow extensions if a nillmove is in the path.
>I do normal extensions and everything else, as I want that null move
>search to fail high... and the best way to do so is to follow checks and
>so forth to prove that "passing" is really ok, showing that the current
>position is good enough that even passing doesn't hurt.

Sounds plausible. My idea is that I search nullmoves with reduced
depth and I don't want to undo that by following extensions. My tree
is smaller and I hope to get to the next iteration by doing that, so
that it will
compensate for reducing my depth because I did not follow the

Some time ago I did a statistic of cutoffs ( its actually in the
version of Patzer ) and noticed that nullmoves get the highest success
rate ( 70 to 90 % iirc ), so I never thought of changing my way to do
When I find the time I will try both ways on BS2830 or LCT2.

I think that I have read something like that ( we reduced the depth,
so we won't increase it by doing a extension ) in the Crafty source.
Could be a year ago or so.

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