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. Last Updated: 07/27/2016

Kasparov and Deep Blue Draw

World chess champion Garry Kasparov had IBM supercomputer Deep Blue on the ropes Wednesday, but had to settle for a draw, leaving the score even after the fourth game of their six-game match.

Wednesday's marathon draw maintained the high drama of the first three games. Kasparov opened play with another masterful innovation, venturing into an unknown variation of the Slav defense. Deep Blue was immediately forced to retreat, and by the 15th move it appeared that the champion had several fruitful avenues of attack open to him.

On the 25th move, the champion drew gasps from the crowd with a brilliant advance of his rook to the e4 square -- seemingly setting up, in conjunction with his aggressively-placed queen, an attack of Deep Blue's king.

But almost the next instant, Deep Blue suffered a system error and shut down for nearly 15 minutes, sending the Russian flying around the room, stamping his feet and pulling his hair.

The champion fell into time trouble himself after Deep Blue's brief disappearance. Having maintained a leisurely pace for his first 28 moves, Kasparov had to complete a dozen moves in under six minutes. Championship-level players must complete their first 40 moves in two hours.

Kasparov's attack unraveled; Deep Blue recovered. On move 41 it rejected a draw offer, but offered a draw itself on move 50 and was accepted.

Computers have the advantage in timed matches because they think so much faster than humans. Deep Blue can consider 50 billion chess positions in three minutes, although it did take nearly 15 minutes to make move 48 of game 2, when it apparently had difficulty accepting that it would be forced to cede a pawn to its human foe.

Like humans, computers play faster in the opening stages of games, when they can rely on preconceived or "book" openings to dictate their moves. Part of Kasparov's strategy has been to stray from known openings in order to slow the computer down.

Master-level players said after the match that Kasparov's dominance of the opening in the last three games indicated the Russian was gaining on the computer after an opening-game loss.

"Garry has been attacking very effectively," said Eric Johnson, an assistant director of the Chess Federation of America. "His creativity is really showing. We all expect him to win."