Soviet dance commentators, asked to sum up the hallmark of the Kirov ballet, now performing at Wolf Trap in its first visit to the United States in 22 years, inevitably point to the 203-year-old troupe's unflagging devotion to classical form in an era of modernization and experiment in dance worldwide.

Maxim Krastin, Kirov director, stressed the company's strict adherence to the classics in an interview in the blue-and-gilt theater here before the company's departure for its current tour. "The Russian classical school started in this city," he said, "and the tradition here is to be true and loyal to it."

Elsewhere on the tour, which includes Vancouver and four U.S. cities, the troupe planned a modest tiptoe into innovative choreography, Krastin said. But for its shows at Wolf Trap, it is sticking to the cream of classics, "Swan Lake," and a medley from its repertoire.

"We wanted to show our strongest side," Krastin said.

In Leningrad, the old czarist capital, upholding the Kirov's continuity with its roots -- which reach deep into czarist court life -- is the work of a team of choreographers, directors, and dance teachers, as well as dancers. At the top is Konstantin Sergeyev, 76, who, as a former dancer and choreographer and head of the Kirov's dance school, has left his mark on nearly all of the troupe members who will perform in Washington.

The Kirov's foothold on classic form is as much a result of the Leningrad ambiance as of training, Elena Suritz, a Moscow-based Soviet ballet historian, said in an interview.

"In contrast to Moscow, which is full of alleys and winding streets, Leningrad is a city of very orderly straight lines and majestic vistas. The Kirov is that way, too," she said. "Every arm will fall exactly in its place, every head will turn perfectly on cue. Even the Bolshoi innovates more," she said, referring to the world-famous Moscow ballet.

The Leningrad school, Krastin said, is defined in large part by "the perfect position of men and women, and the precision of the implementation of the author's idea."

The training of the Kirov's dancers, too, from their selection to their retirement, is a matter of science as much as of art, Krastin said. In the end, the selection of Kirov dancers is "a scientific and methodological" process, he explained. "Medical specialists have the final word."

After they have spent about eight years in the Kirov's school, the ballet takes its pick of the best dancers. Their careers begin at 18 and go on for an average of 20 years.

In its colorful history, the Kirov's role as a standard-bearer of classics has gained it worldwide renown and influenced ballet everywhere. But it has also exacted costs, including the loss of some of the world's most celebrated dancers.

In 1911, in a show of conservatism, the Maryinksy, the Kirov's forerunner, forced famed dancer Vaslav Nijinsky to resign for appearing in tights considered too risque.

Nijinsky's voluntary exile to Paris was followed by other departures from the ballet -- to Moscow, or the West. In two much-publicized defections, Rudolf Nureyev left the company in Paris in 1961, and Mikhail Baryshnikov followed in 1980 in Toronto.

Much of the Bolshoi's talent started off at the Kirov -- including Yuri Grigorovich, the Bolshoi's chief choreographer, and Nina Timofeyeva and Lydmilla Semenyaka, two veteran ballerinas.

"The American classical school has adopted a lot from the Leningrad classical, too," Krastin said.

The point was vividly made in 1962, when Russian-born George Balanchine, a dancer and choreographer, brought his New York ballet to the Soviet Union. He stunned audiences with his transformation of old Russian classics into contemporary American style. "He took the best of what we had and breathed life into it," Suritz, the ballet historian, said.