Computer Chess Club Archives


Search

Terms

Messages

Subject: Re: Rook & Pawn Ending with Perpetual Check and Stalemate

Author: Bruce Moreland

Date: 09:16:20 03/31/01

Go up one level in this thread


On March 31, 2001 at 09:22:57, Ferdinand S. Mosca wrote:

>Hi everyone,
>
>A position from an actual game which caught my interest while
>playing an engine match at G60.
>
>[D]3r4/5k2/5p2/6pp/5p2/1p6/p2R4/K3R3 b - - 0 1
>Is there any program that can evaluate this simple ending logically.
>
>The trap here is the move ...Rxd2, this may not win but it only draws.
>There is perpetual check and stalemate if black plays ...Rxd2. Many programs
>probably find the perpetual coming, but at what time do your favorite programs
>give a 0.0 or near 0.0 score?
>
>If it finds the perpetual check, which it can find, would a program dare to play
>the black side kr+pawns vs. krr?
>
>This position is actually not a draw but a win by black.
>I think ...Rb8 will win or maybe other moves.
>
>[D]3r4/5k2/5p2/6pp/5p2/1p6/p2R4/K3R3 b - - 0 1
>
>Regards,
>Dinan

This one is very hard because it will be difficult to force black into the same
position twice.  I've seen this happen in practical play between my program and
Genius, back in 1996 or so, where Genius couldn't win KRR vs KR, because my
program had its king on a1, Genius had its rooks on the b-file and the 2nd rank,
and mine did the desperado rook thing for 50 moves.  I believe I've seen it in
other cases, too.

It may be possible to solve this problem by searching deeply enough to notice a
direct win down a rook.  That would allow the score to climb up above the huge
score you'll get for collecting the rook.

bruce




This page took 0 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.