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Subject: Re: Crafty endgame position

Author: Mike Hood

Date: 15:09:51 04/07/02

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On April 07, 2002 at 17:46:35, Mike S. wrote:

>On April 07, 2002 at 14:41:20, Mike Hood wrote:
>
>>(...)
>
>>This is a matter of opinion. I think that today's chess programmers have the
>>right to assume the use of 5-piece tablebases.
>
>I would strongly recommend *not* to rely on tablebases, at least not for major
>parts of endgame knowledge (i.e. bacic mates).
>
>The assumption that everybody uses 5-piece tbs., is wrong:

I don't assume this. All I'm saying is that in the computer program's handbook
there should be a note saying something like "The CD contains all the 3-piece
and 4-piece endgame tablebases. If you want to increase the program's endgame
knowledge you can download 5-piece tablebases free of charge from the ftp site
....."

>First, not many people, except computer chess fans, even know what tablebases
>are. Tablebases are expert's stuff.

I agree. However, their is a two-tier market for chess programs. My contention
is that only an "expert" would buy a program like Fritz or any of the other top
chess programs. You have to be an insider to have even heard of Fritz. A
"normal" customer decides to buy a chess program, so he walks into a store and
picks up either Chessmaster or Corel Chess off the shelf, goes home with it and
is overjoyed with his good purchase. I've never seen Fritz 7 or Rebel Century on
the shelf in a high street store -- have you? And even if by some fluke Fritz 7
is on sale, the relatively high price and the relatively unattractive packaging
will make the customer choose Chessmaster anyway.

>Second, 5-piece tablebase are not always an advantage. I even doubt that they
>are an advantage in more than, say 60% of practical positions, when accessed
>during the search.

When aren't they an advantage? The only fault I could possibly see is if a chess
program accesses the tablebases too early, ie in a position where it is unlikely
that exchanges will lead to a tablebase position within the next 15 or more
moves.

>As a consequence of that, I use 4-piece tablebases only
>+RB-R, RN-R. (For 5-piece endgame analysis, I still have the Thompson tables
>available.) A possible disadvantage may sometimes not be visible, because both
>sides are affected.
>
>Third, AFAIK most programs don't access tbs. in the quiescence search (AFAIK
>only Nimzo does that with it's NCD tables). Which means, missing knowledge can
>not be replaced in the quiescence search by using tbs.
>
>I think it is a big danger for (professional) programmers, to adapt too much to
>the type of users who are computer chess experts. This is an audience of a
>limited number IMO. If your program is sold in big shops and can't do something
>without 5-piece tablebases, 10 of 100 customers will say the program can't do it
>at all (5 will use tbs., and 85 will not notice it at all :o).
>
>But OTOH I think, most major programs have much built-in endgame knowledge, and
>do not rely on tablebases too much anyway.
>
>Regards,
>M.Scheidl



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