Author: Bruce Moreland
Date: 10:33:53 12/15/00
Go up one level in this thread
On December 15, 2000 at 04:50:30, Dieter Buerssner wrote:
>Thanks. I took the five minutes to try this out. I get an interesting PV
>
> 1 0.206 0.00 1t : 1.Be2 {-160}
> 8 0.207 0.00 1. : 1.Be2 {-160}
> 32 0.210 0.00 2t : 1.Be2 h2 2.Bc4 {-160}
> 55 0.218 0.00 2. : 1.Be2 h2 2.Bc4 {-160}
> 138 0.222 -11.59 3--: 1.Be2 g2+ 2.Kg1 Bc5+ 3.Kh2 g1=Q# {-1081}
> 189 0.237 -Mat03 3t : 1.Be2 g2+ 2.Kg1 Bc5+ 3.Kh2 g1=Q# {-1081}
>
>A you can see, the position is evaluated as draw. But also, one trap can be
>seen. Even after Be2, the position is still evaluated as draw.
>Of course this is no problem here at all, because in no time Kg1 will be found
>as the correct drawing move. But there will be the fear left, can such a
>position occure deep in search, but the win is after the horizont? I think
>the answer must be yes. But more interesting: Will this be a practical problem?
>Your story shows, that it can work very well in practise.
>
>Regards,
>Dieter "collecting little bits of chess knowledge suitable for programs" Bürßner
This is an interesting issue. There are some cases that can be called draws,
and yet there are mates possible with some degree of practicality. An obvious
example is KB vs KB, which is a draw but it's possible to construct a mate.
This one is obviously much more dangerous than KB vs KB, but I consider them
both to be in the same category. I bet that it is possible to declare both of
these drawn with a good degree of safety, but only *at the endpoint nodes*.
Some endings such as KB vs K, or the simple impotent pair case (from the
original diagram, remove white's bishop and white's g-pawn), are drawn no matter
where they occur in the tree, but I think the safest thing to do with this one
is only declare it drawn at the endpoint nodes. That way the program can steer
for it, but by the time it gets close to there it can get a little search under
the critical position and angle for a better case if necessary.
bruce
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