It was a night of serious, single-minded tap dancing yesterday at the Kennedy Center, as the first of the weekend's Jazztap programs took shape on the stage of the Terrace Theater. Two performances of a single bill had been planned, but one of the four featured dancers -- Howard "Sandman" Sims -- was late returning from an engagement in the Netherlands and Brenda Bufalino took his place alongside Harold Nicholas, Savion Glover and Baakari Wilder. Sims is scheduled to appear tonight.

All four dancers concentrated on tapping, with very little other step material interwoven into their solos or the ensemble number that concluded the program. Yet, each performer had a distinctly personal style that was expressed not only in movement but in aspects of dress. Washingtonian Baakari Wilder, a young 13, wore a tux too large for him and this gave him a zoot-suited look. It matched his high-stepping, excited and exciting manner. Technically, there's nothing immature about Wilder. He's quick, controlled and can also slouch like the best of old men. A habit he has of veering from side to side in his footwork may look coltish but is never imprecise.

Savion Glover, a mature 16, has a fighter's build that made his tux seem too tight. He's getting tall, developing a stride and he plants his feet wide apart. Tapping, he's strong, punchy and superfast. Occasionally, he'll launch into a sharp slide or a set of resounding double leg-beats. Definitely a virtuoso and never soft in motion, he can be subtle rhythmically. Those in the audience who hadn't succumbed already did when he broke into smiles.

Bufalino displays a sense of humor that has a sad strain, and there's something suggestive of a clown in the way she cuts her hair and wears male attire. Her tapping isn't visually ostentatious but seems to be done for the sake of musical values. The very clear tones and rich echoes she produces sound symphonic

Harold Nicholas is nothing if not elegant. His tux is cut to perfection. His step is light, and his torso pliant and stretched. He's a performer in the Astaire style of romantic urbanity, and when he sings there's no gravel in his voice, only a few smooth pebbles. The musicians who accompanied his vocalizations and some of the dancing -- pianist Jon Ozment, bass player Tommy Cecil and drummer Warren Shadd -- were nicely understated when providing background but knew how to surge when they became the focus of attention. One factor in the program didn't match the dancers and musicians. It was the lighting, which was sometimes too red or too blue, diminishing visibility.