EDINBURGH, SCOTLAND, AUG. 12 -- Mstislav Rostropovich and the Saito Kinen Orchestra under the baton of Seiji Ozawa raised Edinburgh International Festival fever to a high pitch tonight in the opening concert of Scotland's annual celebration of the arts.

The Slavic virtuosity of National Symphony Orchestra Music Director Rostropovich and the robust precision of the largely Japanese orchestra were perfect complements in Dvorak's Concerto for Cello and Orchestra in B Minor, Op. 104, and the audience responded by calling Rostropovich back four times. Three times he returned arm-in-arm with Ozawa.

Rostropovich was also warmly received by the orchestra, made up of former students and teachers at the school of music run by the Japanese master educator Hideo Saito. The players, who gather for a few weeks each year, could barely refrain from joining the applause for Rostropovich. But they enjoyed the full glare of the spotlight later as the sellout crowd in the city's elegant Usher Hall cheered their rousing performance.

The opening concert of the festival has long been a signal for this august city to enter into its annual rite of August, and this year will be no exception as the artistic extravaganza begins in earnest Monday.

The Edinburgh Festival, conceived as a way to breathe life into the shellshocked capital of Scotland after World War II, has blossomed into one of the world's largest and most prestigious arts events. This year more than 60 opera companies, orchestras, theater groups and dance companies have taken up residence during the three weeks plus of artistic outpouring.

The two themes -- "Performers From the Pacific" and a celebration marking the centennial of the birth of the Czechoslovak composer Bohuslav Martinu -- are loosely represented by such diverse groups as the Bolshoi Opera, the Slovak National Opera and Ballet, the Korean National Theatre and three contemporary Japanese theater troupes.

A varied American contingent includes the San Francisco Symphony Orchestra with Yo-Yo Ma, the American Indian Dance Theatre, the Flying Karamazov Brothers and the Music-Theater Group of New York. So packed is the program that the appearance of Rudolf Nureyev had received little notice as the festival began.

Tickets can be as elusive as a hot Scottish day, and no wonder with tickets for the Bolshoi starting at only the equivalent of $11.

Yet the official festival is just the beginning, and anyone out for a stroll cannot fail to notice that all the city's a stage. Overshadowing the festival proper, at least in terms of numbers and accessibility, is the Festival Fringe, which the Guinness Book of World Records calls the world's largest performing arts festival.

The hilly streets are alive with the sound of hucksters trying to attract an audience for 10,000 performances of 1,100 shows by 537 groups in 140 venues. More than a half-million tickets are expected to be sold on the Fringe this year.

And then there is the jazz festival -- this year featuring an "East Meets West" gala with Czechoslovak, Hungarian and American bands -- and a film festival. A void created by an off year in the biennial book festival is filled with meet-the-author sessions. And just in case a visitor still has the time and energy, the Edinburgh Military Tattoo, a sort of all-singing, all-marching extravaganza of martial arts (not the karate kind) dishes up an evening of highlights of the British empire.

The Edinburgh Hamada Festival already offered two no-expenses-spared, money-losing productions by Zenya Hamada, a retired Japanese real estate magnate. Hamada still has money to spend, however, and has announced that on Monday, he is donating nearly a million dollars for a festival foundation.

Decorum tends not to be the order of the day as the street bazaar cum lesson in market forces unfolds and patrons contend with 110 pages of Festival Fringe listings alone. Fringe performances range from established Britons such as comedian Spike Milligan, rocker Tom Robinson and the Hull Truck Theater Company, to a production of "Macbeth" on an island in the estuary of the Forth River (ferry included in price), to a group of "luscious busty students, four of whom are men" who present a review of medical student humor.

Perhaps as a bow to sometimes obsessive-compulsive, nonstop theatergoing, the Fringe Marathon is being revived this year. The Scotland on Sunday newspaper, otherwise responsible, is offering a prize to whoever can take in the most productions in the 24 hours starting Friday at 4 p.m. In case of a tie, the winner will be the contestant with the best costume.

The last winner managed 23 shows in 24 hours. His odyssey was made more comfortable by an air mattress strapped to his back.

Once again, the American contingent is the largest from abroad, with 40 groups coming from as far away as Hawaii. They range from Baltimore's well-organized BAT Productions, with a 27-performance run of an American production of "The Phantom of the Opera," to the Festival Theatre U.S.A., the 15th Edinburgh offering from the University of Southern California that this year includes a four-week run of 10 shows including "Oklahoma!" and Sam Shepard's "Hawk Moon."

Sure to attract at least curiosity is the Kuma Kahua Theatre Company of Hawaii, presenting European premieres of two works combining traditional Hawaiian and modern theater styles. And someone wanting to take a bit of a chance could always pay $10 to see the Reduced Shakespeare Company of Los Angeles in "The Complete Works of William Shakespeare (abridged)," which it advertises as "37 plays ... one low price." It may sound iffy but in fact, the group has received favorable reviews here in the past.

But why would a group come 8,000 miles and lose a good deal of money in the process? Mari Little, Fringe press officer, says performers here "can make themselves well known and take themselves on new careers." Dudley Moore, Peter Cook and Jonathan Miller, for instance, were virtually unknown before making their names at the Fringe. A Fringe first award from the Scotsman newspaper can help performers even in the United States, Little said.

The challenge of coming, surviving and even counting a theatrical coup or two seems to be the main attraction for American groups, however. Paul Bedington, in Edinburgh with his second run of the professional Ensemble Arts Theater of San Diego, said of last year: "We had a terrific time. And it was a contact high by being at a month-long theater convention."

This year the company, whose members in San Diego donated $10,000 to send it over, is doing two shows and hopes to improve on last year's attendance of 2,000 in 16 performances -- a good figure for a hall seating 150.

But there are pitfalls aplenty. A community college group from Baltimore one year put on its first performance 34 hours after leaving Dulles Airport -- in a hall it didn't see until the day before. Worse, 30 minutes before the show started, not a theatergoer was to be seen. The group was relieved, however, when a Fringe flourish all but filled its 25 seats, and even laughed at the right places in its "H.L. Mencken Tour of Baltimore."

Unlike some British performers who have been stranded in Edinburgh -- a former Fringe director tells of lending one person five pounds to get home -- U.S. groups at least always have a ticket home. That was what the Gone Fishing Theatre Company of New York thought -- at least until Iraq invaded Kuwait. The company flew over on Kuwait Airlines but the airline has closed down and other airlines won't honor its tickets. The members don't have the $1,000 for new tickets and fear their drama in Edinburgh could run and run. Rosalind Riley, a member of the group, said, "We are trying to put it out of our minds and not let it affect our performance, but as time goes on it gets increasingly difficult. We could end up begging."