Author: Robert Hyatt
Date: 16:21:09 11/03/01
Go up one level in this thread
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?
>
>Incidentally, just so that I cover my back and prove that I'm not being totally
>stupid, Crafty v18.11 static evaluation scores this as +6.20 for white.
>
>Cheers,
>Col
Try it with a simple search:
1 0.02 0.73 1. d6
1-> 0.02 0.73 1. d6
2 0.02 -- 1. d6
2 0.02 0.00 1. d6 e3
2-> 0.03 0.00 1. d6 e3
3 0.03 0.20 1. d6 e3 2. Kb5
3-> 0.04 0.20 1. d6 e3 2. Kb5
4 0.04 0.00 1. d6 e3 2. Kb5 e2 3. d7 e1=Q 4. d8=Q
4-> 0.04 0.00 1. d6 e3 2. Kb5 e2 3. d7 e1=Q 4. d8=Q
5 0.05 0.00 1. d6 e3 2. Kb5 e2 3. d7 e1=Q 4. d8=Q
The point is that once a move is made, the die is cast. And the evaluation
becomes correct... The original position has two plans... which give a
static evaluation fits... fortunately that is why we have a search to help
the evaluation. :) One move resolves the position..
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