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Subject: Re: New Discovery: Summary And Sanity Check

Author: Bruce Moreland

Date: 02:07:05 11/26/98

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On November 26, 1998 at 04:41:15, Graham Laight wrote:


>Given this claim that a big new discovery has taken place, may we just recap
>what we're discussing here, please?
>
>Correct me if I'm wrong (I probably am, because I haven't been following the
>thread in detail), but my understanding is as follows:
>
>In DB V GK 97 game 2, DB played 36. axb5.
>
>This is a move one would not expect a computer to play, because it misses an
>opportunity to win material with 36. Qb6, which is what one would expect a chess
>computer to do.
>
>Those who believe that DB found the move for itself, without help, have, in
>support of their case, stated that DB would have been able to see that 36. Qb6
>leads to a forced draw.
>
>To discover if this is true, Bruce Moreland has asked that as many people as
>possible should run the position for as long as possible on their own computers,
>to see whether, at some depth of search, the eval for 36. axb5 jumps ahead of
>the eval for 36. Qb6.

I'm hoping that someone will get lucky with a search extension or whatever, and
that this will more or less prove that it is possible to understand Qb6 in
finite time.

Best would be another program that played axb5.

Second best would be that something gets a score drop such that the value of the
position is < +1.00.

We can argue about what this means, if it happens.  But I don't think it is
going to happen.  I think everyone is going to get Qb6 +1.X.

>In doing this, Ernst Heinz has discovered that, at ply 21, a line of
>continuation that includes move 40. Ra6, appears to push the draw too far into
>the distance for any computer to have a realistic chance of seeing it.
>
>This adds to the case that 36. axb5 is not a move one would expect a computer to
>make, and therefore supports Gary Kasparov's view that the move requires further
>explanation from IBM.
>
>Right or wrong?

No.  I was somewhat concerned that if this search failed, people would assume
that IBM is cheating, but this doesn't follow.  If I go looking for something
and I find it, that is a good indication that the thing exists.  But if I don't
find it, it doesn't prove that the thing doesn't exist.

So I think that we are back to square one, although we've shown that an obvious
brute force attempt to disprove the cheating notion fails.

My personal opinion is that DB figured this position out better than the rest of
us have.  I have no evidence that supports this.  I don't think there is any
evidence for cheating, either.

bruce



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