Anatoly Karpov, an underdog for the first time in more than 10 years, laxed and unworried about that position today as he prepared to begin his fight Monday to regain the world chess championship.

"I have done my work of preparation," he said. "Now, we will see whether I have done it correctly."

*Sitting comfortably in the four-story town house that will be his headquarters here, Karpov was even able to joke about the greater popularity of new champion Gary Kasparov's flamboyant style.

"There is no need to ask whom most of them will be applauding," he said cheerfully.

And he turned philosophical when asked if he considered this match the most crucial of his career.

"The importance of this match cannot be really judged for at least 10 years," he said. "All that has happened in the past is unimportant, impossible to bring back to life. Nobody can live on past successes, especially in sports. You can write memoirs and histories, but in the end you must try to succeed in real life."

*His remarks were made during a nearly two-hour conversation over lunch at the town house, where he will stay until the match moves to Leningrad in August. The 35-year-old Karpov -- who was reportedly near nervous collapse when his first match with Kasparov was called off in early 1985 after five months of play -- seemed relaxed, happy and in good health. He laughed often and seemed optimistic about his chances of winning back the championship he lost in their second match, a 24-game battle that ended last November.

*Play does not begin until late Monday afternoon in the Park Lane Hotel in Piccadilly. But there is already at least one dispute between the two players. Kasparov maintained that they had agreed not to give prematch interviews. Karpov said he agreed only that they should not say negative things about each other to the press -- a condition that he has scrupulously, sometimes painfully observed.

So while Karpov answered questions freely today, Kasparov abruptly dismissed requests for an interview. He said that he would not give interviews until "after the match," months from now. The 23-year-old champion visited the Park Lane today with a large entourage -- including his mother, who quit her job as a research assistant in an electronics firm two years ago to devote full time to promoting and protecting him.

Prowling around the ballroom where the match will take place, Kasparov looked more like an athlete -- perhaps a lightweight boxer -- than a master of a game that combines elements of sport, artistic creation and intense intellectual exercise. Neatly dressed in matching gray shirt, trousers and tie with a zippered windbreaker, he paced with the sure-footed step of a beast of prey, his eyes darting everywhere to look for possible problems. He conferred frequently in Russian with the crowd of attendants who stayed at his side.

Karpov seemed much less formal and image-conscious, wearing a red knit sports shirt and blue slacks. He came to inspect the ballroom with only one attendant.

Karpov and Kasparov will meet the 750 journalists accredited to the event at separate press conferences today.

Since his arrival Monday Karpov has been strolling through some of the city's many parks as part of his physical preparation for the match. Russian players prepare for a chess match like athletes, with physical as well as mental exercises, and swimming and tennis are also a part of Karpov's physical training. "I am getting better at tennis," he said. "I used to be very weak; now I am merely weak."

Almost immediately after losing the championship last November, Karpov began to prepare for a new match by playing for the Soviet Union in the World Team Championship in Lucerne, Switzerland.

"I think I made the right decision," he says. "It blotted out the match failure in my mind."

He recovered from the pain of loss and resharpened his skills, first in Lucerne and then in Vienna. At Brussels in March, he began to feel satisfied with his play again, and finally he played in his top form in Bugojno, Yugoslavia. "This tournament was most difficult," he said, "because I had to play well without revealing my latest secrets for the upcoming match."

When the return match was postponed from February to now, he said, the delay helped him to "plan my preparation better."

Karpov said the London weather in July and August should be acceptable for the match, but said he would have refused to play here in February and March, when it was originally scheduled. To prepare for the London climate, he moved "from the snow of Moscow's suburbs to the early spring of Tashkent, where there was a lot of sun and a lot of green and nature was waking up from winter's dream."

From previous visits, Karpov is already a seasoned London tourist, with the National Gallery and Madame Tussaud's among his favorite attractions. He said he hopes to visit the British Museum but has not yet found time. He watched Wednesday's wedding of Prince Andrew and Sarah Ferguson on television and said he is "puzzled" at all the excitement about Fergie's wedding gown. "Why do they talk about her dress more than about her?" he asked.

One souvenir he will be bringing back to his 7-year-old son in Moscow is a miniature double-decker London bus. "I love the London buses and taxis," he said. "The taxis are so spacious -- sitting in the back seat, you feel like a king."

Karpov has two places to stay here. One is a suite at the Park Lane, where he greeted visitors in a formal sitting room with an 18th-century painting of a young English nobleman on the wall. On a table stood a chessboard in a complicated middle-game position. The other is the town house, in a secret location away from the heart of London to protect Karpov's privacy.

A world chess champion or challenger, particularly if he is a Russian, is not merely a solitary gladiator but the head of a highly specialized team. Karpov shares this temporary home -- built to look something like a medieval castle -- with seven assistants: a manager, a cook, a chauffeur-bodyguard, a trainer for his physical conditioning and three grandmasters to help him with game preparation and adjournment analysis.

"The villa is beautiful, spacious, located in a good, quiet place, and we fit in here very nicely," he said, standing in a large sitting room, furnished with overstuffed chairs and sofas and decorated with several modern, representational paintings and sculptures.

The dining room, dominated by a 19th-century painting of an aristocrat in formal evening wear, has a mahogany table that seated eight comfortably for a meal that included mushroom soup and beef stroganoff. If today was representative of Karpov's schedule for the next month, he plans to lunch well in the midafternoon, allowing an hour or more for digestion before the games begin at 5 p.m.

No matter who wins the match, Karpov said, "he should continue the work begun by Bobby Fischer, trying to improve conditions in chess. The world champion should not withdraw into himself and consider only his own problems. He should serve as an intermediary between players and the organizers of chess events; sometimes the goals of the organizers clash with those of the players."

Washington Post staff writer Joseph McLellan contributed to this report.