Deep Blue versus Kasparov

Deep Blue and Kasparov played each other on
two occasions. The first match began on
February 10, 1996, in which Deep Blue
became the first machine to win a chess game
against a reigning world champion (Garry
Kasparov) under regular time controls.
However, Kasparov won three and drew two of
the following five games, beating Deep Blue by
a score of 4–2 (wins count 1 point, draws
count ½ point). The match concluded on
February 17, 1996.

Deep Blue was then heavily upgraded
(unofficially nicknamed "Deeper Blue") and played Kasparov again in May 1997, winning
the six-game rematch 3½–2½, ending on May
11. Deep Blue won the deciding game six after
Kasparov made a mistake in the opening,
becoming the first computer system to defeat
a reigning world champion in a match under
standard chess tournament time controls.

After the loss, Kasparov said that he sometimes saw deep intelligence and creativity in the machine's moves, suggesting that during the second game, human chess players had intervened on behalf of the machine, which would be a violation of the rules. IBM denied that it cheated, saying the only human intervention occurred between games. The rules provided for the developers to modify the program between games, an opportunity they said they used to shore up weaknesses in the computer's play that were revealed during the course of the match. Kasparov requested printouts of the machine's log files but IBM refused, although the company later published the logs on the Internet. Kasparov demanded a rematch, but IBM refused and dismantled Deep Blue. Owing to an insufficient sample of games between Deep Blue and officially rated chess players, a chess rating for Deep Blue was not established.