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Subject: Re: To Bob, probably Crafty has an interesting problem

Author: Robert Hyatt

Date: 08:32:09 06/09/01

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On June 09, 2001 at 04:37:32, Joachim Heuser wrote:

>On June 08, 2001 at 22:11:56, Jim Monaghan wrote:
>
>>>Sorry, but 2B's don't always win against a knight.  If you take the
>>>position after Bxf2 Kxf2, and remove the final pawn, this is a dead
>>>drawn tablebase ending.  The KBBKN tablebase will show this pretty
>>>easily.
>>
>>I don't know Bob. This is interesting. In the book "Endgame Magic" by Beasley
>>and Whitworth the authors say in an appendix:
>>
>>"In the absence of pawns, two minor pieces against one is usually a draw, but
>>the special case of two bishops against a knight has been proved by a computer
>>to be a win."
>
>
>I am quite sure that nearly every position from KBBKN is won for the two
>bishops.

Sorry, but you are quite wrong.  Go to my ftp site, cd to the TB/tbs
directory, and download kbbkn*tbs and take a look.  More draws than
wins.




>In the position mentioned above, after Bxf2 Kxf2, Tiger claims Nd7 to be a draw
>(0.01), but after Bxd3 it's mate in 43.
>
>
>
>>I'm not a FIDE rules guru, but I believe the 50 move rule had been extended in
>>special situations of which this_may_be_one. This point has been overlooked in
>>the discussion.
>>
>>Any FIDE rules experts here?
>
>
>I don't know for sure, but i think the rule was extended for a short time to
>cover endgames, where best play is mate >50 (of course without moving pawns or
>capturing pieces).
>After is was discovered that this was the case for quite a lot of endgames, it
>seemed to be too complicated to set a limit for each of these endgames, so the
>rule was returned to 50 moves.
>
>
>Joachim



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