World chess champion Gary Kasparov held on through 40 moves yesterday in Game 16 of the world chess championship. But when the game was adjourned, after five hours of intense play, he wrote down his 41st move and sealed it in an envelope in a position that looked hopeless.

Exactly how challenger Anatoly Karpov will finish off the champion remained to be determined in a session of overnight analysis with his team of experts. But there seemed little doubt that he can do it, tying the match 8-8.

Karpov not only had a crucial extra pawn; his queen, rook and knight were centralized on the key d- and e-files and controlled the strategically vital center. While Karpov's pieces dominated the board, Kasparov's queen, bishop and rook were divided, without coordination, between the two flanks. His king was in a dangerously exposed position.

Kasparov -- who had seemed comfortably in the lead in the 24-game match with a score of 8 to 7 -- will still have a small theoretical advantage if a Karpov victory evens the score because he remains the champion if the match ends in a tie. But a loss to Karpov at this point, particularly in a game where Kasparov is playing white, would give the challenger the match initiative and a sizable psychological advantage.

Whether he wins, loses or draws when Game 16 is resumed today at the Teatro Lope de Vega in Seville, Spain, Karpov is scheduled to have the white pieces (and therefore the game initiative) when Game 17 starts tomorrow. And a win at this point would bring him into the crucial final third of the match with strong momentum.

Karpov's play in this game had almost a textbook clarity and purity of theme. The game was a lesson in how to fight for control of the center; the theme recurred throughout the game, and at the adjournment it was clear that Karpov had played the teacher's role.

As usual when Kasparov has had white in this match, the oblique, subtle English Opening was played. This time, the players went back to the Four Knights Variation, and Karpov showed the subtlety of his preparation with the move 6. ... Re8. After that, he quickly got his opponent where he wanted him, with the black pieces controlling the center and enjoying a lot of freedom.

Kasparov's chance lay in amassing his pawns in the center and opening the lines for his bishops, but Karpov played him the way the matadors play the bulls in Seville's famous Plaza de Toros a mile or two away. In a style for which he has become almost legendary, Karpov was able to develop his pieces with total efficiency. In this game, Kasparov had an experience that was common to Karpov's opponents during his 10 years as world champion: Wherever Kasparov looked and whatever he tried, Karpov already had the right piece sitting on the right square to stop him.

He did not necessarily follow conventional wisdom in achieving this mastery of the position. His 13th move, ... Na5, for example, put a knight on the side, ignoring the chess adage: "Knight on the rim; prospects are dim." But this knight gave Karpov control of the important square c4.

While developing, Karpov created no pawn weaknesses, so Kasparov had no targets to aim at. Then, after keeping his pawns unmoved for a dozen moves (12 through 23 inclusive), he managed to generate huge threats to Kasparov's position with the simple-looking 24. ... c5.

By then, it was obvious that Kasparov was losing his fight to control the d-file and stay in the game. He had to muddy the water, which he did with his 24. f5 -- but, unfortunately for him, it led to the loss of a pawn. His effort to create some kind of magic with 30. f6 was quickly denied when Karpov played 30. ... Qe6, gaining control of both central files.

Then on move 35, Karpov humiliated Kasparov's bishop by refusing to exchange his knight for it. This helped him both to advance his queenside pawns and to secure his kingside so that, at adjournment, Kasparov had no point of entry into his position.

In the last few games, enjoying a significant but not crushing advantage, Kasparov seems to have allowed himself to relax -- saying, in effect, "I have the lead; it's up to Karpov to beat me." This is a very dangerous tactic on such a slender margin, though up until now it has paid off for Kasparov; Karpov has had many chances to equalize the match, but was unable to finish Kasparov off in several games.

If, as seems likely, Karpov wins when Game 16 is resumed today, he may find that he has burned out his creative energy on this effort, and Kasparov may be able to make an easy comeback. Otherwise, the prospect is that the players will continue trading what they hope will be knockout punches through the last eight games of the match.

Kasparov's policy of relaxation may have been premature, but it does not seem likely that his energy is exhausted at this point.

Grandmaster Lubomir Kavalek contributed to this report.