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Subject: Re: a question to Tord about detecting threats in null move

Author: Uri Blass

Date: 09:47:23 10/03/03

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On October 03, 2003 at 12:13:13, Anthony Cozzie wrote:

>On October 03, 2003 at 12:03:49, Uri Blass wrote:
>>I can detect every big threat by adding a special search after making null move.
>>For example if I like to detect threats of at least 2.2 pawns I can do
>>if (val<=beta-220)
>>//ply-1 because I still did not undo the null move.
>small error here: beta should be replaced by eval, or you will have massive
>instability problems.

If I am a queen down in the search and I threat to win a bishop then I do not
consider it as a threat  because a threat is a threat relative to beta.

I believe that Tord does the same(he replied that your example of threating the
queen twice by sacrificing material is solved by extending only big threats so
if you sacrifice a rook and a bishop the threat on the queen is not a big

I think that the idea that an extension should not be dependent on beta is a bad
It is better to have stronger engine with stability problems and not
weaker engine without them.

I prefer even not to care about using hash tables for pruning because my
experience told me that I cannot get significant gain there easily(I have a lot
of stuff that means that pruning or extension is not defined only by the


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