Author: Robert Hyatt
Date: 21:47:17 07/17/02
Go up one level in this thread
On July 17, 2002 at 16:27:48, Amir Ban wrote: >On July 17, 2002 at 11:44:26, K. Burcham wrote: > >> >>You show below that the two programs play 36.Qb6, not axb5. >> >>You are actually strengthening Kasparov's question "how could Deep Blue fail to >>play 36.Qb6 ?". 5 years later, I've yet to see a program that plays 36.axb5. >> >>Amir >> >> >> >>Deep Blue >>Game 2 move 36 >> >>Fritz 7 on 1533 mhz amd with 432 hash, will play 36.axb5 between 39 minutes >> and up to 70 minutes in eval, (see below). >> >>like I said the three positions after blacks move 40 seem equal. both programs >>threaten the same as Deep Blue and will play >>without human interference the moves Be4 and axb5. the newer programs accomplish >>same objective by playing axb5, just not first move in this line. >> >>kburcham >> > >It is needed to understand what the fuss was about here. > >36.Qb6 wins a pawn. Other moves don't. > >Kasparov expected the natural Qb6 and planned in response to give away two more >pawns for an attack, which would have given him some chances. > >Kasparov did not believe any computer can see the merit of giving up these three >pawns. So, when Deep Blue instead played 36.axb5, he asked why. > >There's nothing special about 36. axb5. If you decide not to take the pawn with >Qb6, then this is a natural second choice. > >If the answer to Kasparov's question is that Deep Blue saw the line Kasparov >considered and evaluated it properly, then the question is answered and hooray >for Deep Blue. Otherwise it's still unanswered. > >Amir Their log seems pretty clear to understand here... at depth 8(6) [14 plies total] they liked Qb6 with a score of 87. At depth 9(6) same move, score=79. At depth 10(6) it dropped to 74. At depth=11(6) [final search, 17 plies] Qb6 dropped to 48 and was replaced by axb5 with a score of 63... What is hard to understand there? Their search/eval liked axb5 slightly more than Qb6. About 1/10th of a pawn better, roughly, assuming they still use pawn=128 which I don't know is true for DB2...
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