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Subject: Re: null move (basic question)

Author: Bruce Moreland

Date: 12:26:15 06/29/98

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On June 29, 1998 at 15:03:34, Peter Kasinski wrote:

>Could someone please explain - what does "null move R=2" mean?
>I realize this is a naive question. I actually added (what I thought was) a
>null-move logic to my program and now I wonder.
>In my code I first try a NULL move at all levels of the tree provided that last
>move was not NULL and that a (basic) zugzwang-detection test is passed.

Somewhere in your search you'll have a loop that will in most cases search this
positions successor moves to some distance, say for example, 6 plies.

With null move R=2 you will search the null move to depth 4, as the first
successor move.

You can try other values of R.  Known to be in use are both 1 and 3.

There seem to be two techniques for dealing with more than one null move in a
line.  One is to not allow more than one in a line, if there is a null move
anywhere directly above you in the tree, you don't allow one now.  The other is
to not allow two in a row.  You seem to be doing the second one, which is
perfectly fine.

bruce



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