Author: Peter Berger
Date: 12:34:30 08/28/01
Go up one level in this thread
On August 28, 2001 at 11:58:02, Dieter Buerssner wrote:
>
>However, I don't totally agree, that this is a King safety problem. For many
>depths, Kd6 and Ke8 have almost the same score (or have the same score). Sure,
>fiddling a little bit at KS-values will make Yace "find" the correct move
>muchearlier. I actually lowered some time ago some "K-advance-penalty". But I
>had the feeling, that this makes Yace weaker after some time, so I put back the
>old values.
>
>Also, this position may be a bit unusual, and not fitting some heuristics used
>in many chess programs. Usually programs come out of book, in castled position,
>or with a closed center. Neither is the case here.
>
>BTW. An material only eval, never switches away from Kd6.
I agree and never said anything else. You won't want your engine to play Ke8
here though and lose in about 5 moves if it can be avoided - it definitely is a
king safety problem ( why else would the engine prefer Ke8 anyway ? ) It is an
exception of the usual rule - and it obviously can happen in a game ( as it did
) . Maybe it isn't important as it doesn't happen often.
>
>I think, this position tests more the search of the engine. When Yace sees the
>problem, it gets a fail low to a score < -3. I wondered, why this is seen so
>late.
>
Yes, again agreed . Look at Andrew William's confirmation for PM - it seems the
same happens to Yace here.
>First of all, after 1...Ke8, 2.f3 must be found. To see, that f3 is really good,
>probably (after 2...Bxf3, which is no problem of course), 3. g3 must be found.
>All those moves (and more in the mainline) don't trigger any extensions in Yace.
>OTOH in other lines many extensions are triggered (and are mainly useless). So
>the search depth increases too slowly, and Yace needs too much time.
>
>I think, perhaps finding f3 after Ke8 would be another good test position.
f3 with a good line and eval seems to be hard indeed for some of the engines
that won't find Kd6 .
>
>And - Yace thinks even after Kd6, it will be difficult to hold the game.
>After I have analyzed some lines, and gone back (what you called "cheating" :-)
>I get the following after Kd6:
>
> 16702914 1:27.8 1.55 10t 2.f3 Bxf3 3.Rc2 Bxg2 4.Be1H Be4+H 5.Bg3+H
> Qxg3+H 6.hxg3H Bxc2H 7.Qd4+H Ke7H 8.Qc5+H Kf6H
> 9.Qxc2H h5H 10.Qd1H g5H 11.Kf2H Rh7H 12.Qd8+H
> Kg6H 13.Qd3+H Kg7H 14.Qd4+H {HT} {261}
> 29572054 2:33.8 1.55 10. 2.f3 Bxf3 3.Rc2 Bxg2 4.Be1 Be4+ 5.Bg3+ Qxg3+
> 6.hxg3 Bxc2 7.Qd4+ Ke7 8.Qc5+ Kf6 9.Qxc2 h5
> 10.Qd1 g5 11.Kf2 Rh7 12.Qd8+ Kg6 13.Qd3+ Kg7
> 14.Qd4+ {HT} {261}
I don't get your point here. I agree to your analysis but this is a line where
black is alive and fighting still although its position isn't nice. Ke8 ?? is
dead though.
pete
>
>Regards,
>Dieter
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