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

Author: Joachim Heuser

Date: 01:37:32 06/09/01

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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.
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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