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Subject: Re: chess gods smiling on Cilkchess

Author: Robert Hyatt

Date: 09:28:00 11/25/97

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On November 25, 1997 at 04:00:43, Ernst A. Heinz wrote:

>On November 25, 1997 at 02:04:53, Howard Exner wrote:
>
>>Cilkchess is doing nicely on the scoresheet at the Dutch Championship
>>but it looks to me like the chess gods are smiling on it just a bit.
>>
>>8/p3pp1p/6p1/4P3/2K2P2/6P1/1k5P/8 b - - id"Cilkchess 2.0 - Nimzo 98";
>>
>>Here Nimzo98 played h7-h6 but doesn't the move Kb2-c2 put the nail
>>in the coffin?
>
>Yes, it does -- most chess programs choose the winning Kc2 in a couple
>of seconds (DarkThought eval = +1.3 after 12 sec).
>

oversight or evaluation bug or selective pruning error.  Kc2=+.69 until
ply=11,
then +1.00 through ply=13, hits +1.5 and fails high on that at ply=14.

>>
>>6k1/pp3p1p/2p1p3/P1P2p2/8/1n2P3/1bR2PPP/6K1 w - - id"Shannon -
>>Cilkchess";
>>
>>Here too the Cilkchess team must have been relieved when Shannon
>>played a5-a6. The straight forward Rxb2 would lead to a win and a
>>huge upset given the Cilkchess Hardware. This 2nd position would
>>perhaps be more difficult for computers to eval since the material
>>is balanced. But the Knight is no match for the rook in this ending
>>especially with that weak isolated h pawn.
>
>I do not know if Rxb2 is really won but it obviously offers the best
>winning chances. DarkThought sticks to Rxb2 right from the beginning.
>
>=Ernst=

Crafty also would only consider rb2 here, and I let it run for many
minutes.
But I'm not convinced this is winning at all.  It seems better than
anything
else, but the difference between a knight and rook is often less when a
computer
has the knight, because it can calculate very accurately, while a human
can make
a mistake.  And with a knight, a single tempo can be critical.  the eval
here
was steady at around -.2 through 15 plies (on my notebook) before I
stopped it.

However, none of this is a surprise.  You will find the same sort of
good/bad
luck in games at Paris, Jakarta, Aegon events, etc.  There's a lot of
"luck"
involved, although better programs generally have better "luck".. :)



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