Author: Robert Hyatt
Date: 07:33:15 07/23/02
Go up one level in this thread
On July 23, 2002 at 09:41:10, Ed Schröder wrote:
>On July 22, 2002 at 14:11:23, Robert Hyatt wrote:
>
>>On July 22, 2002 at 11:52:35, Ed Schröder wrote:
>>
>>>The two you entirely miss the point of Kasparov's suspicion, sigh...
>>>
>>>Lesson 61, now pay attention my pupils :)
>>>
>>>[d]r1r1q1k1/6p1/p2b1p1p/1p1PpP2/PPp5/2P4P/R1B2QP1/R5K1 w - - id DEEP BLUE -
>>>Kasparov,G;
>>>
>>>Position before 36.axb5
>>>
>>>Here DB for a long time showed the following main-line:
>>>
>>>36.Qb6 Qe7 37.axb5 Rab8 38.Qxa6 e4 39.Bxe4 Qe5 40.Bf3 Rcd8 41.Qa7 Qc3 42.Bh5
>>>
>>>Now let's have a look at the main-line shall we?
>>>
>>>After 39...Qe5 we get:
>>>
>>>[d]1rr3k1/6p1/Q2b1p1p/1P1PqP2/1Pp1B3/2P4P/R5P1/R5K1 w - -
>>>
>>>As you can see black has sacrificed 3 (!!) pawns for a king attack. And this my
>>>pupils is what Kasparov could not believe, a computer sacrificing 3 pawns and so
>>>he started asking questions how that could be.
>>>
>>>The refusal of IBM to answer Kasparov's questions made Kasparov suspicious and
>>>from one thing came another.
>>>
>>>This is *the* heart of the discussion.
>>>
>>>Ed
>>
>>
>>So? If two _current_ programs think axb5 and Qb6 are equal, what do you
>>conclude then? That we all have similar king safety? That we all like
>>the same move (axb5) but for different reasons?
>
>Again, axb5 or Qb6 is irrelevant. What is relevant is the main-line. Black has
>nothing for the 3 pawns. You don't need to be a GM to see that, you don't need
>the complete main-variation, after 39...Qe5 the picture is clear that black has
>nothing for the 3 pawns, see the above diagram. Yet the mainline is a very human
>approach to establish a) a draw by eternal check or b) looking for counter play.
Do you think sacrificing the three pawns is the _only_ way to proceed after
axb5? Is fritz showing the same sacrifice in its PV after it gets the same
score for both moves? If so, is fritz getting help too? Remember that
Kasparov did _not_ get to see the partial PV from deep blue. And remember
that we don't know what happens in the last N plies of the PV since we can't
see them. Perhaps it found something different than tossing three pawns,
because I don't believe Fritz would sac three pawns and say "equal to winning
a pawn outright" myself.
>
>Kasparov *KNEW* about the mainline (just check your records), exactly *THE*
>reason he started to ask questions.
He knew about what _he_ saw. Not about what DB saw. He knew what fritz
could see after a few minutes. Not about what it could see after weeks of
computing (at that time, since it took almost three days at today's speed to
get the two scores equal).
>
>Bob, this is an issue about chess, not computer chess, try to understand 36.Qb6
>Qe7 37.axb5 Rab8 38.Qxa6 e4 39.Bxe4 Qe5 as a chess player, not as a computer
>chess programmer.
Try to understand why programs are saying axb5 is _just_ as good... which
Fritz did. Crafty got to within .1 after 2.5 days...
>
>I know you entirely want to blacken Kasparov for the public scandal but then you
>should tell history as it happened, here is:
>
>1) Kasparov doesn't understand DB's main-line 36.Qb6 Qe7 37.axb5 Rab8 38.Qxa6 e4
>39.Bxe4 Qe5 and starts to ask questions how a computer who usually sits on every
>pawn suddenly can sacrifice 3 pawns in a row.
OK... but two points: (1) kasparov didn't see db's main line. The main line
is incomplete in any case so what happens to the last N plies is anybody's
guess. (2) fritz and Crafty are _both_ saying that axb5 and Qb6 are identical
after several days of searching. That suggests that either fritz and crafty
at DB speeds would produce the _same_ mystery, or there is something else going
on. At least we can prove that his statement is false.
>
>2) The DB team refuses to answer ("we are not going to tell him our secrets")
>
I don't see a problem with that _during_ the match, which was when he
wanted it.
>3) Kasparov becomes suspicious by the refusal.
He became suspicious because he had encountered something he had not seen
before. And rather than saying "they have created something marvelous" he
chose to go "they are cheating, the machine is too good."
>
>4) The next day the press more or less puts the words cheating (the supposed
>human intervention) into the mouth of Kasparov. Kasparov reacts evasive, but
>suggestive. The accussation is born, the press is happy, a scandal is born.
>
>I withhold myself from a conclusion, my interest is only to list the facts.
>
I never took the time to run a huge search on this move until recently. I
now know that axb5 is perfectly reasonable with no unusual explanation
required. I had always had DBs output. But never thought to run both
moves deeply until recently. And the results were not surprising after I
thought about it. Someone else did the same with fritz and found the same
thing I did, which was supporting evidence.
No mystery. No cheating. Lots of sour grapes of course...
>Ed
>
>
>
>>you can't _see_ DB's full PV. The last 5-6 plies (plus extensions) are
>>hidden by the hardware, so it might not be that those three pawns are
>>forever sacrificed.
>>
>>All we can therefore conclude is that DB liked axb5 better, fritz says they
>>are equal, Crafty says they are less than .3 pawns different with Qb6
>>being better for the moment...
>>
>>no big mystery to me... And remember Kasparov had _no_ access to that partial
>>DB pv so he had no idea what it was "thinking".. We know "part of the story"
>>but that is all. And now that we know the two moves are pretty equal by
>>today's programs, there is even less mystery in it...
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