Game 4 of the world chess championship began with subtle psychological warfare yesterday in Seville, Spain. But five hours later, it had turned into a bloodbath and probably the first victory for defending champion Gary Kasparov.

Challenger Anatoly Karpov, who went into the game with a one-point lead, seemed likely to be driven back to equality by the time yesterday's session was adjourned.

Karpov did not resign, and some experts at the Teatro Lope de Vega in Seville thought he might have chances of holding a draw when -- and if -- play is resumed today; there is a strong possibility that he will simply resign without returning to this game.

Kasparov wrote down his 41st move and put it in a sealed envelope with an overwhelming advantage on the board -- not only two extra pawns, but also two well-protected passed pawns, heading for the eighth rank and the status of queens.

"I think Kasparov will win the position, but it's not 100 percent clear," said U.S. grandmaster and former world junior champion Maxim Dlugy. "Karpov has some chances to draw."

Dlugy was one of a swarm of international grandmasters who sat at tables in the press room spinning out variations on the game, which was played in an adjoining room and transmitted into the room on color video monitors. Comments in English, French, Spanish, German and several Slavic languages bounced back and forth between the grandmasters as they watched the progress of the game and speculated on what might happen next, observers there reported.

The scene will be similar, but more grimly concentrated, and the comments will all be in Russian during the overnight analysis by Karpov and his team of experts. They will be eagerly looking for the drawing chances mentioned by Dlugy -- which seem to lie, if anywhere, in threats against the white king by the black knight and rook.

But with a sealed move like 41. Rd8, Kasparov has excellent winning chances. That move would allow him to advance his d-pawn toward the eighth rank, and he can also check the black king with his rook from f8.

The game was an English Opening, like Game 2 last week, in which Kasparov had white for the first time. The champion lost that game, partly because Karpov had uncorked a surprise move (9. ... e3) that cost Kasparov more than an hour and 20 minutes of thought before he replied.

Repeating the moves of Game 2 up to that point in yesterday's Game 4, Kasparov called Karpov's bluff. He had had five days to ponder that move, and a corps of skilled assistants to help him with the pondering, and Karpov might have preferred not to see what answers they had found. Whatever the reason, he did not repeat the move that had caused so much comment and cost his opponent so much time in Game 2. Instead Karpov chose a more logical and quiet continuation, but one that got him into trouble. He opened the f-file with 9. ... exf3; eventually, that open file played into Kasparov's hands, and he was able to exert pressure on Karpov's position.

Incidentally, that surprise move had been waiting to be played since 1978, when Karpov and his associates prepared it for his championship match in the Philippines against Victor Korchnoi. Korchnoi never gave Karpov a chance to spring it; he brilliantly avoided all of Karpov's home preparation by the variations he chose to play and was able to stay in the match and even tied it at 5-5. Only his impatience and overconfidence led to his disaster.

After 22. Bh3, Karpov's position looked very uncomfortable, and he was forced to drop a pawn by Move 26. He tried to build some kind of a fortress, but the session ended with his king forced out into a highly exposed position.

The score is now 1-0 in Karpov's favor. Six victories are required to gain the championship; if neither player gets six wins, the title goes to whoever is ahead after 24 games. Kasparov retains the championship if the match is drawn at 12-12.

Grandmaster Lubomir Kavalek contributed to this report.