Kasparov Wins, Clinches a Tie Against Machine

PHILADELPHIA — After having his draw offer rejected, Garry Kasparov rallied Friday to defeat Deep Blue and clinch at least a tie in their six-game match.

“Today was a good day,” Kasparov said. “I proved this machine isn’t invincible.”

The 32-year-old world chess champion has two wins and the IBM-designed computer has one. There have been two draws. Deep Blue must win today’s sixth and final game to salvage a tie.

Kasparov can win the tournament and a $400,000 first prize with either a win or a draw. He’ll have the advantage of playing the white pieces, and going first.

Chung-Jen Tan, the IBM team’s lead designer, said he wouldn’t throw in the towel just yet.

“Garry is the best and we are the second-best right now,” Tan said, “though we don’t know yet for sure.”

The IBM team said they rejected the draw offer to test how the machine would react.

“I have got to praise the scientists who decided to continue with the experiment,” Kasparov joked.

Chessmaster Dan Heisman said that it is possible Kasparov didn’t think he could improve his position and decided to end the match with a draw and go for a win Saturday.

“He saw the position and figured that it is even and thought, ‘Let’s go home, we’ll come back tomorrow, and I’ll win,’ ” Heisman said.

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Immediately after his offer was turned down, though, Kasparov improved his position dramatically.

“The computer made a couple of mistakes and Kasparov was able to make some strong moves.” Within 10 moves, Heisman said, “Deep Blue’s position is very bad.”

Deep Blue, playing the white pieces, resigned in its 48th move.

In his 37th move, Kasparov captured a bishop in a play that most chess experts said essentially ended the computer’s chances of winning.

Christopher Chabris is a grandmaster and doctoral student at Harvard University, where he also is a co-organizer of the Harvard Cup, an annual tournament where grandmasters play computers in chess.

He said Kasparov has made much of his desire to defeat a machine, but he said, “I think some of that is to psyche himself up. . . . He likes to feel like he’s fighting for a cause.”