Computer Chess Club Archives




Subject: Some facts about Deep Thought / Deep Blue

Author: Erkki Malkamaki

Date: 05:29:28 08/29/01

This heated discussion about Deep Blue pops up regularly , so here are some
cuts from different articles.

Many of you have already forgotten that Deep Thought in 1990 with 750000 n/s was
pretty strong.

From Scientific American Oct 1990:

"In January of 1988, at a press conference in Paris, world chess champion Gary
K. Kasparov was asked whether a computer would be able to defeat a grandmaster
before the year 2000. "No way," he replied, "and if any grandmaster has
difficulties playing computers, I would be happy to provide my advice."

Ten months after Kasparov's statement, in a major tournament held in Long Beach,
Calif., Grandmaster Bent Larsen, a former contender for the world title, was
defeated by a chess-playing machine we had designed in a graduate project at
Carnegie-Mellon University. The machine, a combination of software and
customized hardware called Deep Thought, won five other games, drew one and lost
one, tying Grandmaster Anthony Miles for first place. Because machines are
disqualified from winning money in tournaments, Miles pocketed the first prize
of $10,000. (Deep Thought nonetheless defeated Miles a year later in an
exhibition play-off match.)

Deep Thought
 By the summer of 1990--by which time three of the original Deep Thought team
had joined IBM--Deep Thought had achieved a 50 percent score in 10 games played
under tournament con-ditions against grandmasters and an 86 percent score in 14
games against international masters. Some of these games and dozens of others
against less distinguished opponents had been played under the auspices of the
U.S. Chess Federation, which used the results to derive a chess rating of 2552.
That rating indicates a playing strength in the bottom half of the grandmaster
range. An average tournament player, by contrast, is rated around 1500. In the
games played after August of 1988, when the computer reached its current
analytical speed of 750,000 positions per second, its performance rating
exceeded 2600. "

About chess chips:

Post to CCC from Richard a Fowel 1998:

Subject: Deep Blue article excerpts (IEEE Computer, Oct.

      [ Post Followup (without quoting) ] [ Post Followup (with quoting) ] [
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Posted by Richard A. Fowell ( on January 11, 1998 at 02:56:43:

Since the perennial:
"how would Rebel/Hiarcs/etc. do if they had the same nps as Deep Blue"
topic is threatening to resurrect itself, it occurred to me that I
might not have posted this summary of a few nuggets of information
about Deep Blue's internals that were published in IEEE Computer
Magazine, Oct. 1997.
Hamilton, Scott, and Garber, Lee, "Deep Blue's Hardware-Software
      Computer, Oct. 1997, pp. 29-36.

The 7-page article discusses Deep Blue's ASICs in some depth.
The article is based on interviews with Hsu and Campbell, and Campbell
reviewed early drafts, so hopefully the facts are mostly correct.

Some tidbits:

* The ASIC evaluation function recognizes roughly 6,000 features
    in hardware.
* The weights of these features can be adjusted by the governing
  software on every move (!)
    ["Program software recomputes the evaluation coefficients after
      each move, and downloads new values to the ASIC"
       p.32, 3rd from last paragraph]
* "On-chip evaluation now comprises about two-thirds of the chip area"
* "the endgame heuristics and a few small endgame databases
   are actually on the chip"
* The choice of weights was largely tuned manually with the aid of
  visualization tools.
* The team believes that Deep Blue's evaluation function is now
  superior to those of the top commercial programs.
   (first para, page 32 - which also refers to single-chip matches
   against other programs in "debugging mode")
* The ASICs are 1.7 million transistors in 0.6 micron technology.


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