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Subject: Re: Extended square of the King rule

Author: blass uri

Date: 03:57:11 06/12/00

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On June 12, 2000 at 05:46:59, Rémi Coulom wrote:

>On June 10, 2000 at 13:44:35, blass uri wrote:
>
>>On June 10, 2000 at 11:54:17, Ed Schröder wrote:
>>
>[...]
>>>
>>>Maybe the opposite is true. It depends per program how the programmer
>>>looks at things. For this position I would say that having 2 outside
>>>passers usually is a great advantage and as such is rewarded by a chess
>>>program. If so then this position is an exception to the rule. And the
>>>end-game is full of exceptions much more than the mid-game.
>>>
>>>Ed
>>
>>Having 2 outsides passed pawns is an advantage but having 2 advanced passed pawn
>>is also an advantage.
>>
>>The problem is to know which advantage is bigger.
>>
>>I agree that it is not a simple problem and I understand the fact that
>>programmers prefer to waste more time about other problems.
>>
>>I still believe that it is possible to see it at evaluation time by an array
>>64*64*64 of distance to promotion.
>
>You are perfectly right about this idea. I do it in TCB. I have a table for
>distance to promotion for KPK and PPK. In fact, it is not really a table of
>distance to promotion, but a table that gives the maximum number of "not a King
>move by the opponent" before the pawn is promoted. I call it "extended square of
>the King". It is not in the latest version of TCB. I will make it available in
>the next version. If programmers are interested in the code to generate the
>table, I will send it to them.
>
>PPK is nice, but KPK is probably much more useful. TCB can solve WAC #100 in 25
>seconds or so on a celeron 400 thanks to it. It saves 3 or 4 plies as compared
>to the standard "square of the Pawn" rule (or is it "square of the King"?). It
>is also very good at detecting that a pawn can win a tempo by checking the
>opponent on its way to promotion.
>
>I do not think it would solve this position though. I am not a good chess
>player, but the position after the Queen exchange seems unclear to me. Black can
>promote first, but White will promote on the next half move. Is it a winning
>advantage? Or I might be missing something. I will try it on TCB when I am back
>home.
>
>Greetings,
>Remi

black can promote first with check so white can never promote.

Uri



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