Game 12 of the world chess championship was played to a quiet, 21-move draw yesterday in Seville, Spain. At the midpoint of the 24-game match, champion Gary Kasparov now leads challenger Anatoly Karpov 6 1/2 to 5 1/2.

Karpov was wiped out by Kasparov Tuesday in Game 11, losing as traumatically as possible -- by a blunder when he seemed headed toward a victory. But he has evidently recovered some self-confidence. He must win at least two games (Kasparov remains champion if the match is tied), but there are 12 more games, and a soothing draw or two at this point might give him the strength to push for victory later.

Kasparov must be aware of how lucky he is to be ahead. He could easily have lost a couple of games but didn't; Karpov could have won Game 11 but threw it away. Had Karpov won, Kasparov would now be the one feeling pressure, which will mount steadily with each game. But if Karpov is patient enough, he may still have a chance to come back.

In Game 12, for the first time in this match, Karpov transposed his opponent's English Opening into a Queen's Gambit, in a variation that was heavily tested by the two players in their 1985 world championship match in Moscow.

The first critical point of the game arrived after Karpov played 6. ... Bf5, inviting Kasparov to take a pawn with 7. Qb3. Karpov's idea would then be to play 7. ... Nc6; 8. Qxb7, Nb4. This has been explored in the games of E. Ubilava, one of Karpov's seconds. The pawn sacrifice has not been considered quite correct, and the percentage of won games has favored white in this variation. But Kasparov, playing white and leading in the match, prudently avoided running into a home-prepared continuation. Instead, he played a few solid moves, and when he finally played 11. Qb3, Karpov was ready to oppose with his queen.

The result of the opening after 13. ... g6 was clear; white did not achieve much. In the final position, black has no apparent weaknesses and is ready to meet any white pawn advances on the kingside or in the center.

Grandmaster Lubomir Kavalek contributed to this report.