"For sure" is a young person's motto, a password to the world of youth to which the cellist and conductor can return only as an important alumnus. He has entered the youthful musical world at Curtis Institute of Music to conduct the Curtis Orchestra in a benefit concert today at 8 p.m. at the Academy of Music. The concert will celebrate the beginning of the school's 65th year and will warm up the students for the concerts they will play in May, when they will be the orchestra-in-residence at the Evian Festival in the French Alps. Rostropovich is also head of that festival.
Even for these musicians, who are accustomed to working with world-class conductors, Rostropovich is something special. He is, first, Russian - heir to another musical tradition. He is his generation's pre-eminent cellist, the man for whom Shostakovich, Prokofiev, Britten, Walter Piston and Lukas Foss have written major works. He has conducted opera and orchestral concerts in the Soviet Union and has frequently concertized at the piano with his wife, mezzo- soprano Galina Vishnevskaya. And since shortly after arriving in this country, he has been music director of the National Symphony Orchestra in Washington, having been transformed instantly from red star to American national emblem.
He also is the man whose outspoken criticism of the Soviet system in the 1960s and '70s led not to prison but, in 1974, to his release - at a time when peaceful departure for dissidents was virtually unheard-of.
Rostropovich carries all this history with him when he stands on the podium. But at a rehearsal Monday, he was the broadly smiling colleague of these musicians - the big, affectionate bear given to embracing all comers.
Shostakovich's Symphony No. 6 is one of the pieces on the program that the students will play. For the orchestra, it is a complex work that presses them near the edge of their technical skills. For Rostropovich, it is both a kind of tribute to the composer and a work of such high emotion that, after an hour, Curtis dean Robert Fitzpatrick whispers, "That's 'take no prisoners' Shostakovich. . . ."
To reach the fever pitch Rostropovich wants in this music, he gropes for images.
"You have a very hot fire," he tells the strings. "You put your finger in your mouth and touch the fire. Psst! psst! That's how that note should sound: Psst!"
Later, he tells the violins to play like chickens - and he crows and clucks in tempo while his players laugh. Then, having driven the orchestra through a difficult passage five times, he announces: "Self-service."
A week ago, the students might have considered the announcement an invitation to partake of cafeteria food. Rostropovich, however, is translating a Russian phrase that tells the players to practice the section - right then.
While they are battering at the notes, he pulls off his vest, loosens his tie and stands with his head tilted, listening to the anarchy produced by self-service laundering of complex music.
"Shostakovich was my teacher," Rostropovich says during a rehearsal lull. ''I conducted this work for him. He had seen me conduct many of his works - and I had seen him conduct the only time he ever did. That was when we premiered his cello concerto.
"I had asked him to. He was shy, very shy, but he was very good. He conducted with great attention to detail. That was in Gorky. Before we played, I went to the director of the theater and said I would pay for him to put up microphones and record the performance. He refused and told me it was of no interest to them.
"No interest," he repeats.
He drives the players through the symphony for 90 minutes, beginning in the last movement and skipping toward the beginning. He demands rhythmic precision, but offers broad brushstrokes for the phrasing. He asks the timpanist to polish a solo passage, pushes the harpist through a quick arpeggio to get the right voicing and emphasis, sings over the orchestra to reveal the cello line, and even goes to the piano to play an oboe solo while illustrating the harmonies beneath it.
In an earlier rehearsal, he needed to make a point that his English would not permit. So he took principal cellist Wendy Sutter's instrument and let his bow explain. "Before we started working with him, I was very nervous," Sutter recalls.
"I love working with a student orchestra," Rostropovich glows later. ''They take, take, take what I give. They have not yet preconceptions. And they are so fresh.
"You know, when I conduct this music, I am somehow unsettled. Shostakovich was my teacher, but I feel unsettled. You see, in Russia we have the custom of funerals with an open casket, or glass-covered one as it is put in the ground. I could not be at Shostakovich's funeral, so I feel our relationship is incomplete. I play this music and I am troubled.
"Will I feel better when I go back to Russia this summer?" he asks, referring to the Soviets' recent extraordinary invitation for him to conduct the National Symphony in Moscow. "That invitation shows how much things are changing there. I thought my name might someday go back to Russia, but not my body. It would be possible only after I am dead.
"But now I go back, and my wife and daughters will go with me. I don't know if that will make me feel complete about Shostakovich, but I know I am very excited to go back. That's for sure."