Author: Dave Gomboc
Date: 18:03:33 08/09/99
Go up one level in this thread
On August 09, 1999 at 20:29:49, Robert Hyatt wrote:
>On August 09, 1999 at 19:05:06, Dave Gomboc wrote:
>
>>On August 09, 1999 at 12:24:56, Robert Hyatt wrote:
>>
>>>On August 09, 1999 at 10:02:42, Bernhard Bauer wrote:
>>>
>>>>Hallo,
>>>>
>>>>recently I came across a position from a game
>>>>Haenninnen - Szabo, Wageningen.
>>>>
>>>>The position is
>>>>FEN: 3r1rk/pp1q2b/3p2pp/PP1Np2n/2Pp1p/B2P2Pb/3QPPBP/R4RK w
>>>>
>>>>The game went on
>>>>19. Bxd6 Bxg2
>>>>20. Bxf8 Qh3
>>>>21. Bxg7 f3
>>>>22. exf3 Bxf3
>>>>23. Ne3 Kg7
>>>>24. Qb4 Rd7
>>>>25. Ra2 Nf6
>>>>White resigned.
>>>>
>>>>Programs have difficulties to find out that 19. Bxd6 is bad.
>>>>The whole line seems to be difficult at least for Crafty.
>>>>BTW Crafty produces a lot of debug messages on a Sun, not on a PC.
>>>>
>>>>Enjoy
>>>>Bernhard
>>>
>>>
>>>What is "a lot of debug messages"? If you are getting oddball error messages
>>>then something is definitely wrong...
>>>
>>>As far as the position goes, the end has a B on F3, Q on h3, which is a known
>>>"null-move" killer...
>>
>>Would it be too costly to detect that there is a bishop on f3 and a queen on h3
>>and an unprotected g2 or h1 and decide to extend? :-)
>>
>>Dave
>
>No.. but it would be costly to detect Qh3 and P/B at f3, or a B at e4, d5, c6,
>b7 or a8, or a Q at f3, and a B/P at h3, etc...
>
>Same 'general' case, but different from the computer's perspective... :)
>
>Bob
I thought the point of bitboards was so that you could get the bishop's entire
diagonal quickly? :-)
More seriously,
(
(if white king is on g1)
and
(
(
(if g2 is not defended other than by the king)
and
(if black attacks g2 both with a queen and something else)
)
or
(
(if h1 is not defended other than by the king)
and
(if black attacks h1 both with a (queen or rook) and something else)
)
)
)
then prevent static eval (prevent q-search / extend / whatever)
"attacks" should include "x-ray attacks" too...
Obviously it could be made more or less complicated, for more or less cost.
It's not terribly general, but IMO it's at least as general than that hack to
stop taking "en prise" minor pieces with one's h-pawn. :-)
I imagine that much of the information needed for the above is part of what is
tracked as make-move / un-make-move is done in some engines.
Dave
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