Pavel Necheperenko, the world's leading balalaika performer, was coaxing sweet, mournful Russian folk songs from his instrument with small, muscular fingers that moved so fast his hands became a blur. He was explaining to rapt listeners that he keeps motions to a minimum, always saving energy.

"Human nature," the revered Moscow master explained through an interpreter, "has through the ages always aimed to spend as little energy, but do as much as possible. It is very important to make use of the human form as it is, to get as close to the heart of human nature as possible."

It may come as a surprise, for strangers to the balalaika, that such an obscure instrument could point toward such universal truths. But that's what this week's convention of the Balalaika and Domra Association of America is all about.

About 150 men, women and children are here from around the country -- and six from the Soviet Union -- for a week of playing the folk music of Eastern Europe, dancing its dances and, when the serious work is over, imbibing its vodka. Some take part because it is their heritage; others, because they love the music.

Necheperenko, 75, the featured guest at the convention -- whose lectures several players likened to listening to the gods -- observed that one needn't be Russian or even Eastern European to excel in the balalaika, the domra or other traditional instruments of the region.

"Of course every culture has its own identity," said the snow-haired artist. "But every person has a soul, a heart, a human spirit. You just have to want to do it. Once a person starts, the appetite grows with the meal."

So the American balalaika and domra players have found. (The balalaika, of Dr. Zhivago soundtrack fame, has a triangular body; the domra's is rounded). Many of the players were born to immigrants in Slavic communities in the United States, raised on balalaika music and now hold onto it as their cultural identity. But even those who came to the instruments through love of music have been drawn into the dancing, the language, the culture.

They were also moved to meet their Soviet counterparts, and have been arranging Soviet-American exchanges of balalaika players since well before the people-to-people movement came into vogue. Russians, Ukrainians or Byelorussians have been coming to the group's U.S. conventions since 1985.

Joel Leonard, president of the Washington Balalaika Society, cautioned that it's much easier now, however. "In earlier years, one Soviet musician was always KGB-trained," he said. "We'd ask what his line of work was and he'd say, 'communications specialist.' "

This year, the first secretary of the Soviet Embassy in Washington, Natalie P. Semenikhina, was an honored guest at the group's opening luncheon. She hailed its work as "people's diplomacy."

The climax of the convention is to be a Russian festival balalaika concert on Saturday at George Washington University, featuring an orchestra of 125 American and Soviet balalaika and domra players who have been practicing all week, plus feature performances by Necheperenko and several ensembles.

But the cultural exchange goes on all week. In one room, Mia Gay, an Estonian-extracted Russian instructor at the University of Arizona in Tucson and a domra player, was teaching basic Russian to 20 Americans of all ages.

In another room, David Cooper, a domra performer from Atlanta, was teaching balalaika to children -- three of them the offspring of Zeny Ocean, a dentist from Reno, Nev., who learned the music from his grandfather, a Ukrainian writer, editor and poet who emigrated to the United States in 1915, became an auto worker in Detroit and passed the culture on to his children and grandchildren.

In another, New York balalaika artist Leonard Davis, who learned balalaika in a Russian church group at age 8 and played "Lara's Theme" in the Dr. Zhivago soundtrack, was reuniting with Necheperenko, whom he had met once, 25 years earlier. Davis had traveled to Toronto in 1965 to hear the world master play, and Necheperenko had invited him to his room.

Davis recalled their meeting: "He said, 'You came all the way from New York to see me? What can I do for you?' I asked him to show me the masters' techniques. He had me playing for four hours. My fingers were bleeding."

In yet another room, Lyubov Matriychuk, a domra instructor from the Kiev Conservatory, was playing with dozens of Americans. She showed an observer that she had goosebumps from discovering so many domra players here. It was her first trip to America, she said, and she was struck by the standard of living.

"We hope in a very few years it will be the same for us," she said. "We have to continue to struggle and work hard and do our best." She smiled, then added, in Necheperenko's spirit of the universal: "That's life."