Authenticity is difficult to analyze, easy to perceive. When Mstislav Rostropovich conducts the works of Dmitri Shostakovich, you hear the undisputable credibility, the rightness of the performance. Even without knowing about the two musical giants' friendship and frequent collaboration, you can hear the "real thing" in the music. Besides authenticity galore, there was great joy in Davies Hall at the Thursday matinee, the elderly audience attending these concerts fairly rocking to the fun of the first half, responding warmly to the beauty of the conclusion. Smiles and outright laughter were the rule both in the orchestra and the audience during a wonderfully raucous performance of Shostakovich's 1954 Festive Overture, an exultation that followed the death of the composer's murderous nemesis, Joseph Stalin, the previous year. With gleeful irony, the brief piece reflects Stalinist gigantism, with a pinch of Respighi, a dash of Leroy Anderson, waves upon waves of "really big sound," climaxing with the addition of extra brass (located on the loge, above the full orchestra), reminiscent of the Boris Godunov coronation scene. "Festive," oh, my! Ding-dong, the warlock's dead. As the slightly bent, but still commanding figure of Rostropovich (who turned 79 yesterday) held friendly sway from the podium, San Francisco Symphony musicians - as, indeed, do their colleagues all over the world - played their hearts out for the extraordinary cellist, wise and knowing conductor, a sweetheart of a colleague and mentor, albeit one with a less than crisp beat. During the good-natured orgy of the overture, the dizzy blur of the First Piano Concerto (about which more later), Rostropovich enjoyed making music as much - or more - as the audience was delighted in hearing it, but at the high point of the concert, there was a transformation, an experience of which great musical memories are made. A Largo to remember Shostakovich's 1937 Symphony No. 5 is well-known, much-discussed, representing a turning point in the composer's struggle with Stalin, a work offered as a concession to the dictator, actually subtitled (although not by Shostakovich) as "a Soviet artist's reply to just criticism." Knowing the historical background, catching overt and covert musical references in the score can enrich listening, but the strength of the work is in its "absolute," non-programmatic music. Rostropovich led a brisk, energetic first movement, string sections responding splendidly, woodwind and brass performing solidly; the second and fourth movements went well, although tempi seemed on the slack side at times. And yet, all that receded in the memory against the experience of the third movement. This Largo, with its unusually divided strings (three groups of violins, two each of violas and celli), is a contemplative, serious, "sincere" movement, with magical sonorities. Then, in the middle of the movement, Rostropovich took the orchestra and the audience to another place: critical listening stopped, thinking ceased, one got lost in the work, happily, and the music swept everything along its gentle but inevitable path - truly, a magic moment. Piano follies deluxe Yefim Bronfman's steely fingers and Glenn Fischtal's brilliant trumpet solos contributed mightily to the excellent execution of the 1933 Piano Concerto No. 1. This encyclopedic, bright work - with its many references to Shostakovich's favorite composers, ranging from Haydn to Mahler - received a con brio performance not only in the third movement so marked, but throughout. From the jazzy-contemplative first movement, to the second movement's lyricism-without-excess, to the rush (in several meanings) of the finale, there was so much to enjoy in the piece. There was a Transfigured Night feel (without an actual quote) to the slow movement, as once again, the orchestra's strings - led by assistant concertmaster Mark Volkert in the principal violin position - laid an opulent carpet under the woodwinds and brass. Bronfman and Fischtal had more fun than proper classical-music players are normally allowed to have, and by the Spike Jones-wacky finale (written before Jones' Beetlebum ever roamed), there was that unusual senior-matinee excitement in the audience again. Authentically so. Note that there is more celebration of the Shostakovich centennial this week in Davies Hall (http://www.sfsymphony.org/), led once again by Rostropovich - a musical event that's simply a must. "Janos Gereben" <[log in to unmask]>