Computer Chess Club Archives


Search

Terms

Messages

Subject: Extended square of the King rule

Author: Rémi Coulom

Date: 02:46:59 06/12/00

Go up one level in this thread


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



This page took 0.01 seconds to execute

Last modified: Thu, 15 Apr 21 08:11:13 -0700

Current Computer Chess Club Forums at Talkchess. This site by Sean Mintz.