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Subject: Re: Tough solution

Author: Robert Hyatt

Date: 05:01:10 01/15/98

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On January 15, 1998 at 05:35:18, Amir Ban wrote:

>
>You mean because black looks at the score and resigns ?
>
>This position looks to me truely unsolvable, tactically or positionally.
>The main problem is that even after the sacrifice on b3 it's a long way
>to seeing a win (I am taking the book's word on it, it's not obvious to
>me).
>
>I think the only hope to solve here is if we are able to assign a plus
>score to the position after Qxb3. If we have this, we still need the
>hash to conclude that shuffling the queen is a draw, which doesn't look
>easy either.
>
>Just offhand, I don't see any basis for having a plus score for the Q
>sac on b3. Such positions with the same piece & pawn configuration are
>almost always a dead loss for white.
>
>Maybe we can break the problem into two easier parts:
>
>- Who sees a plus score for Qxb3 ?
>- Who sees a draw score for only shuffling the queen ?
>
>Amir


I disagree.  I have seen Cray Blitz and Crafty win many such positions.
It
takes a lot of time, but being ahead +12 is *not* going to draw if the
program
understands the 50 move rule and repetitions.  IE sooner or later it is
going
to see that another couple of queen moves draws.  And it is going to
then
search for a way to push a pawn, or capture something.  Being ahead +12
is
enough to allow the queen sac and still remain far enough ahead in
material
to win.

In 1986 we had a game somewhat like this at the WCCC in Germany.  Except
we were only up 1.5 pawns or saw.  After about 30-35 moves of shuffling,
Cray Blitz found what we already knew... it had to give up its pawn, but
then could win.  It did, but only when urged on by the threat of a draw.
I think many programs would win this, assuming the game is played for
another 45 moves.  +12 is simply not going to draw.  Now if we are into
"elegant" wins, and if this has to be solved *now* or never, then we
have
a problem.  But I've never seen a +12 position that wasn't winnable,
except for a few that are close like Q vs bp...



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