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Subject: Re: NULL move, general principle -- possible alternative

Author: Torstein Hall

Date: 08:35:07 09/30/99

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On September 29, 1999 at 20:49:23, Bruce Moreland wrote:

>On September 29, 1999 at 19:54:01, Dann Corbit wrote:
>
>>For NULL move, we have two kinds of situations:
>>
>>0.  A move is so bad I wish I did not have to make it because I would rather
>>skip a turn.
>>
>>1.  An opponent's move is so bad they would not want to make it because they
>>would rather skip a turn.
>>
>>In the first case, it seems we do not need to consider this move unless there
>>are no alternatives.
>>
>>In the second case, similarly unless the *opponent* has no alternatives.
>>
>>What I am wondering is "why is the loss of a tempo the magic dividing line?"
>>
>>It seems the dividing line could be put anywhere we want.  Has anyone
>>experimented with a floating [don't bother looking here] line that can be
>>redefined during run time?  I know this sounds a lot like ordinary alpha/beta
>>but what I mean is to change the threshold for null-move to something other than
>>the normal value.
>
>I haven't tried to deal with the first part of this, but I can handle your
>question a paragraph from the end.
>
>The reason you skip a move is in order to determine if the opponent has a
>threat.  If their is bad and they don't even have a threat you have to counter,
>you are probably doing great.
>
>bruce

Just a probably stupid question to satisfy my curiosity!
Do you have to extend after the null move? Lets say the oponent can take a
Bishop with a Queen, but that would loose the Queen next move etc. etc.?

If you not extend, would that not keep reasonable moves down "on the list" and
keep you from seeing a lot of good moves?

Torstein




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