India sent its greatest living musician to Washington for the inaugural concert of the yearlong, nationwide Festival of India last night in the Kennedy Center. The featured attraction was Ravi Shankar, and by the end of the evening all exasperations had dissolved in euphoria. It is impossible for a musically sensitive person to leave a Shankar concert not feeling better than when he arrived.

Earlier, there had been problems, including traffic jams, paranoid-level security arrangements and the molasses-like movements of a crowd not accustomed to finding seats in the Concert Hall. The guests of honor, Vice President Bush and Prime Minister Rajiv Gandhi, did not arrive in the presidential box until 15 minutes after the program was scheduled to start. And the first half of the evening was given over to "Kalyana Saugandhikam," a Kathakali dance drama whose tiny subtleties of expression must be lost to most of the audience in an auditorium as large as the Concert Hall.

But after the intermission, everything went right. On Saturday night, at a sold-out concert in the Baird Auditorium, Shankar will give a solo performance, but last night he demonstrated the subtle, exhilarating art of jugalbandhi (duets). For more than an hour, he engaged in musical dialogue at the highest level with the sarod virtuoso Ali Akbar Khan, who is also one of the world's greatest instrumental players.

Both musicians have been friends and colleagues since boyhood, when Shankar studied with Khan's father, Allauddin Khan, and they interact musically with the instinctive, almost intuitive rapport of twin brothers. Their instruments, closely related in form and potential, nonetheless contrast enough to give special point and flavor to their dialogue, and both perform at a level where technique has been totally assimilated into musicianship, always available and used as needed but never flaunted for its own sake.

They performed two ragas, a timeless, ever-fresh musical form that includes ingredients of melody with implications of mood and time of day. In combination with the tala, the chosen rhythmic pulse, this is used as a basis for improvisation in a variety of styles that may occasionally recall jazz or flamenco music. Although the form, in performance, suggests total freedom, the improvisation is bound by a host of rules. "There are many do's and don'ts," Shankar remarked in conversation a few days ago. "It takes a long time to become free."

In last night's performance, he and Khan demonstrated that they have taken that time and used it well. In this musical form, the culture of India has developed an almost perfect balance of freedom and restraint, and these two performers embody that balance to a dazzling degree.

Both pieces performed last night progressed from a calm, meditative opening section through episodes of increasing intricacy, speed and frenzy, arriving at breathtaking final climaxes. In western classical music, probably the closest equivalent to the general effect of this form can be found in the "Hungarian Rhapsodies" of Liszt -- music based on the art of Hungarian Gypsies who probably came originally from India. But the Liszt compositions -- written down and performed always approximately the same way -- seem curiously rigid and circumscribed in comparison to the free flow, the spontaneous give-and-take of a duet between Shankar and Khan.

Joining them in the second raga, and taking the spotlight for a long, brilliant sequence of solos and duets, was the father-son team of Alla Rakha and Zakir Hussain on the tabla, or drums. The carefully controlled virtuosity of these artists added greatly to the effect of the concert.