The Japanese avant-garde dance troupe Sankai Juku was hailed by a standing, cheering audience after its full-length evening performance at the Warner Theatre Friday night, and it was easy enough to see why.

The five-man company headed by Ushio Amagetsu had already set Washington agog with its outdoor prelude last Wednesday afternoon -- a slow writhing descent from the roof of the National Theatre, the performers hanging upside down suspended by their ankles.

The nonstop, 90-minute performance at the Warner, of an abstract but highly theatrical dance-drama titled "Kinkan Shonen" ("The Kumquat Seed"), was no less spectacular in its way. Again the performers appeared with shaved heads, whitened faces and bodies, often in near-nudity. Again they molded their limbs, torsos and faces in a slowly evolving continuum of bizarre, sometimes grotesquely distorted shapes. This time, within the Warner proscenium, their body sculptures and digital gesticulations were framed by a craggy-textured, cavernlike set, extremely high-contrast lighting, and an enveloping wall of sound, ranging in idiom from ancient Asian to contemporary western modes.

There is a point at which technique -- in this case, exacting anatomical control and brilliantly deft stagecraft -- ceases to be merely a means to an end, and becomes a thing to marvel at in itself. This is certainly the case with Sankai Juku -- one is awe-struck from the start by the wonders of muscular strength, fluidity and coordination the troupe evinces, as well as by the seamless unity of theatrical effect.

At the same time, "Kinkan Shonen" leaves one with a certain disenchantment. All that dexterity, all that imagination -- but ultimately, what is communicated? Sankai Juku professes to be aiming at fundamental truths of existence. The subtitle of "Kinkan Shonen" is "A Young Boy's Dream of the Origins of Life and Death." But if one sweeps aside the metaphysical fustian of the program notes, the clever illusionism, the deliberate grotesquerie, the vague symbolism and the surface oddity, there doesn't seem to be much left of artistic substance or impact. It's a dazzling show, but when the curtain calls are taken to a prodigiously icky arrangement of the "Goin' Home" tune from Dvorak's "New World Symphony," it dawns on you that you've been watching nothing more than an exotically stylized, sensationalistic, existential soap opera.

Amagetsu founded Sankai Juku in 1975, as an offshoot of a post-Hiroshima movement in Japanese modern dance known as Buto, with roots in archaic Japanese ritual and German Neo-Expressionism. Earlier this year, the troupe performed at the Olympic Arts Festival in Los Angeles.

But the profundity that's often been ascribed to Sankai Juku's performances wasn't in evidence from the Warner staging. "Kinkan Shonen" proceeds in seven continuous scenes, many of them abounding in striking imagery. In the first, the "boy" (Amagetsu, in short pants) is seen through an oblong of glass with a red circle at its center, like an enlarged microscopic slide. He falls back "dead," rises, contracts into fetal position, plays with, kicks up, eats and spits out white sand. In the second, four white-masked men huddle into eerie clumps, and bare their behinds in a bottom-swaying striptease. In the third, Amagetsu hugs and teases a live peacock. In succeeding scenes come images of combat and caress, of fish mouths and undulating fins, and a final "hanging" like the one at the National. In the most compelling scene, a dwarfed Amagetsu, armless in an oversized cloak, rises with a crazed smile from infant waddling to full adult height, jigging to the crescendo of a repeated bagpipe-and-drum tune, the whole passage suggesting a contorted life cycle.

Eerie, evocative, exquisitely performed and shrewdly calculated to astound -- all this must be conceded. But an ingeniously devised mirage of a pond ought not to be confused with an ocean -- the depth here is all sleight of hand.