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Subject: Re: Endgame Analysis

Author: Uri Blass

Date: 05:32:24 11/03/01

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On November 03, 2001 at 07:07:55, Colin Frayn wrote:

>OK, this is probably the stupidest post you'll ever read on CCC.
>
>Take the following completely trivial endgame position;
>
>[D]8/8/8/3P3k/K3p3/8/8/8 w - -
>
>It's obvious to anyone who's ever vaguely heard of chess that this is a draw.
>
>However, if one carefully codes in the promotion squares algorithm, it's clear
>that the white king can catch the black pawn, but the black king cannot catch
>the white pawn (as it has the move).  Now, the problem is that (obviously) if
>the white king attempts to catch the black pawn then of course the black king
>moves one square closer to the white pawn, and can now catch it.
>
>So, statically, how do you say that this is obviously a draw?  Bear in mind that
>you have to be careful about similar positions where the extra square advantage
>given by the side with a passed pawn having the move might make all the
>difference.
>
>This has got to be easy, right?

I think that you can say that if both kings are at distance one from the
queening square then it is usually a draw.

There are other cases when programs misevaluate unstoppable passed pawn.

Here is an example from my correspondence game

[D]7k/6pp/8/p2B1P2/4P3/5KP1/2r5/8 b - - 0 1

A lot of programs like a4 because they do not understand that after
a4 e5 Rc5 Ke4 Rxd5 white has an unstoppable passed pawn.

I do not say that a4 is not winning without pawn endgame but I believe that
black has a simple win by Rc5 Ke3 a4 Kd4 Rb5 and it was not important for me to
check if a4 is winning when if there is a win the win is certainly more
complicated.

I was very disappointed from Shredder5.32 that was supposed to be good in
endgames because shredder was also one of the programs that fell to that trap
and it needed more time than other programs that I tried to find Rc5.

I was also disappointed from shredder when it did not find Rb5 after Kd4 and
prefered Rc2 when white may make the life of black harder by Kd3 Rg2 e5 Rxg3+
Kd4 Rg4+(Rg1 is another possibility to check) Kc5 Rf4 e6 Rxf5 e7 Re5 Kd6 Rxe7
when maybe black wins the game(I did not check it) but I see no reason to get
into these complications.

After Kd4 Rb5 yace was very happy and saw almost 5 pawns adavntage for me after
many hours.

It seems that white needs to sacrifice the bishop for the a pawn.

Shredder for some reason likes Rc2 even after 2 hours of analysis and I did not
give it more than that because I prefer Yace that proves itself to be a better
program at least in that position.

I believe that Yace is even better than Deep Fritz here when Deep Fritz is at
least better than Shredder

Uri



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