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Subject: Re: Singular extensions

Author: James B. Shearer

Date: 18:01:42 01/10/98

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On January 09, 1998 at 13:54:00, Bruce Moreland wrote:

>The extension is:  If you discover that you get mated if you do nothing
>in this position, extend all your moves by a ply (in total, this doesn't
>add to other extensions).
>
>The idea is that if I'm getting mated if I do nothing, I probably want
>to resolve this node a little better than usual, since perhaps the moves
>I can make that avoid mate are just pushing it over the horizon.
>Especially in cases where you give up huge material at the root, and
>your opponent can give bits of it back to delay things (as in this
>case).

       I don't understand why this helps a lot.  A problem with null
moves is that they can push mates over the horizon.  For example I
was recently playing a crafty clone on a chess server.  The clone
with black had kg8,rf8,pf7,pg6 and ph7.  I had qg4 and bf6.  Black
made a bad move after which it had to sac its queen to avoid qg5,qh6
qg7 mate. Black did not see this because the sequence: black move,
qg5, null move, qh6, null move, qg7 mate is 10 ply pushing the mate
over the search horizon (in a blitz game).  By the time you see
doing nothing will get you mated it is already too late.
                          James B. Shearer



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