Challenger Anatoly Karpov switched defensive systems in an attempt to neutralize aggressive world champion Gary Kasparov in the sixth game of their title chess match Wednesday. After the complex, heated competition of the match's first four games, Karpov seemed intent on slowing the pace of the contest.
Karpov, defending the black pieces, gave up the sharp Zaitsev variation against the Ruy Lopez, deviating from their earlier games on move nine.
The challenger selected a system evolved by Mikhail Chigorin, a Russian grandmaster from the turn of the century. The system leads to solid positions, geared toward canceling out white's advantage of the first move.
Kasparov, who arrived four minutes late for the start of play, seemed unprepared for Karpov's opening strategy shift.
For the first time in the match, Kasparov spent much more time than his opponent on the game's opening stage.
After 17 moves the champion had used over half an hour more than his adversary, a significant difference which could bring Kasparov trouble later in the game.
Karpov looked confident and well-prepared for the game. "I don't think Kasparov is going to win today," U.S. grandmaster Nick de Firmian said.
Despite the challenger's brisk and assured play, many grandmasters said Kasparov maintained a slight advantage after the opening stage.
"I wouldn't say Karpov has equalized _ it's still annoying for black," said U.S. grandmaster Larry Christiansen.
Kasparov leads the match 3-2, with one win and four draws. He needs only a 12-12 tie from the 24 game series, divided between New York and Lyon, France, to retain the crown.