It's stunning to come upon something altogether fresh and first-rate out of the blue. Through the exhilaration of excellence there's added the force of discovery, of revelation even. Such was the case Saturday night at the Washington Project for the Arts with the appearance of Hannah Kahn and Dancers, a small troupe out of New York founded in 1974 and making its Washington debut with this program.

The first, but also a lasting, impression one has of the company and the work they do is of energy - high energy sustained over the length of a composition and accentuated by galvanic bursts at moments of climax. These dancers - four women including Kahn, and one man - beam out voltage continually, in motion and also in repose. The air crackles with physical excitement.

The second thing one notices is the virtuosity of the dancers. The intensity and intricacy of the dances - all by Hannah Kahn - demand technical facility well beyond the routine, and these people have an abundance. Kahn, Teri Weksler, Diane McPherson, Catherine Sullivan and Mark Taylor - all of them have lean, sleek, tightly sinewed bodies - move with surgical precision and edge. The ensemble is airtight, impeccable. Yet there is no feeling of a machine - they're eachof them individuals, each brings a personal bent to the movement. These are major-league dancers, and in the case of Weksler who emits a special nervous vibrancy and rapture all her own, one senses an extraordinary level of magnetism.

Despite the unremitting charge of the dancing, none of the five pieces shown seemed overly busy or dense. Which brings us to the third and possibly most significant attribute of the program: the sturdiness, appeal and originality of the choreography.

Kahn graduated from Juilliard and also studied with Cunningham, Sanasardo and others, but there is no classifying her choreographic idion. She's created a dance language of her own, rich in invention, clear and forceful in form, unerringly musical, exceptionally vivid in dynamics and rhythm. The style stresses a sharp elasticity of the torso; quick, flicking, semaphoric movements for arms and legs; and intricate phrasing within an expansive concept of space.

Kahn also has the knack of investing the solos in her works with a kind of ecstatic abandon that makes them not just digressions but high points. And she also has the advantage of a "house composer" - three of the pieces have music by Mitchell Korn, whose ostinato-based idiom is no less interesting than Kahn's choreography. Here's hoping the group returns to Washington soon and often.