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Subject: Re: Mate in 7 Question + Singular extension

Author: Robert Hyatt

Date: 19:59:44 01/09/98

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On January 09, 1998 at 21:03:51, Howard Exner wrote:

>On January 09, 1998 at 17:45:31, Bruce Moreland wrote:
>
>>
>>On January 09, 1998 at 14:26:44, Howard Exner wrote:
>>
>>>r3rk2/ppq2pbQ/2p1b1p1/4p1B1/2P3P1/3P1B2/P3PPK1/1R5R w - - id"Seiriwan -
>>>Sokolov,A"; bm Qxg7+;
>>>
>>>Is this an example of a singular extension mate theme?
>>>Will this be difficult to solve as a Queen and rook are
>>>sacrificed followed by the "quiet" Bf6?
>>
>>I don't know whether these mates are efficiently found with singular
>>extension, that was just a nasty rumor that I started.
>>
>>I don't know if singular extension is good for anything.  The paper that
>>I read originally about it claimed a pretty big benefit from this, but a
>>subsequent paper claimed much more modest benefit, and there were
>>caveats that the reason it might work for DT could have something to do
>>with DT's search, which was pretty sloppy near the tips.
>>
>>Absolutely no offense to DT or DB or DT or Hsu or Campbell, but, I think
>>the two statements taken with the largest number of grains of salt by
>>this community in the last ten years are:
>>
>>1) Botvinnik had a working chess program.
>>2) Singular extension is mythical and magic.
>>
>>I don't know of anyone who will make a statement of the form:  "I/We do
>>singular extension, it helped us a lot, we proved to ourselves that it
>>is a good thing, and for you guys who are curious, here is a position
>>that we think it helps a lot in, and here is some other cool info
>>involving lots of other interesting numbers, for instance, look how many
>>more we get in the ECM suite with this!"
>>
>>If someone wants to make all or part of the above statement, I would be
>>delighted to hear it.
>>
>>This problem is very hard for my program.  I do not know why.  I suspect
>>it is hard because white goes down a tremendous amount of material and
>>doesn't get it back immediately.  This is similar to Wac 141 (for me),
>>although harder.  Mine is apparently vulnerable to this sort of thing.
>>
>>I bet other programs get it quickly.
>
>I am always interested in the problems that program X finds quickly
>while program Y struggles. It makes me curious as to what makes them
>tick. Rebel 8 for example finds WAC 141 rather quickly but has a very
>hard time finding this above mate in 7. I think it is the quiet move,
>Bf6 that is the stumbling block for Rebel.
>
>I'm not a programmer but follow with interest this recent Singular
>extension thread. It sounds like a similar technique humans employ
>of giving themselves two moves in a row to help determine tactical
>candidate moves.


what you described is exactly how null-move search works...



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