Tamper with some ballets and you'll lose the essence. "Sleeping Beauty" is like that, but "Don Quixote" isn't. Marius Petipa, who choreographed both works, changed his own mind about "Don Q" between its Moscow premiere in 1869 and its production in St. Petersburg only two years later. Since then, a horde of other revivers have had to face the task of making a palatable dish from problematically diverse ingredients. This weekend it was the turn of veteran re'gisseur Nicolas Beriozoff, who mounted his version for the Richmond Ballet, performing in Richmond's Mosque theater.

Slapstick, satire, adventure, mystery and pathos are all components of the story. The choreography calls for character ballet, classical ballet and dancing in between. The music, sometimes refined but often raucous, is choppy. Yet in all this there are plums.

When Moscow's Bolshoi last toured "Don Q" here, it submerged the story in waves of brilliant dancing by the whole cast. American Ballet Theatre's production asks for plenty of flash from the principals, but the aim is fun at all costs. Beriozoff's version is very gentle. Comedy holds sway, but in no outrageous way. The heroine, Kitri, is demure in rejecting Gamache, the suitor her parents prefer. Basil, the bridegroom of Kitri's own choosing, is no rake. He even marries her long before before the last act. Gamache and Kitri's other admirer, Don Quixote, prompt audience sympathy, not just laughter.

There is difficult choreography mainly for Kitri and Basil. The large crowd on stage serves either to participate in mild medleys of ballet and character steps or frame the principal dancers and actors. Beriozoff himself, now 80, was Gamache. This solid little man's simple motions, timed to perfection, vibrated through the vastness of the Mosque. Kitri and Basil were performed by two guests from the National Ballet of Canada, Yoko Ichino and Kevin Pugh. She is a turner, with a proud back that ennobles her strong balance. He, spontaneously airborne and an all-around technician, makes the grand manner warm and friendly. Except for Nesbit Hatch's Don and Norvell Robinson's Sancho Panza, the Richmond Ballet (now a professional company) served only as a background. But the Richmond Symphony and Canadian guest conductor George Crum lent importance to the Ludwig Minkus music.