Profound, perplexing Sankai Juku

The lobby was jammed. When an anxious crowd tried to press into an understaffed Boston Opera House recently to see Sankai Juku - the popular new Japanese avant-garde dance company - chaos erupted. Irate people pushed and shoved, while others tried to relax and wait out the storm.

When we finally burst through the two small openings to the theater, there was a tremendous feeling of release, of calm and order restored.

Watching Sankai Juku is very much like the above scenario: It is a form of dance-theater that speaks of tension and release, anxiety and peace, confusion and order.

Especially when they dangle from the tops of ten-story buildings. Before each major performance, the Sankai Juku dancers stage a public ''hanging'' in each city they visit. At these events, four of the dancers - covered with white makeup, their heads shaved, and nearly naked - are lowered down the side of a tall building by ropes wrapped around their ankles, while they hang upside down, dancing with their arms and upper torso.

Sankai Juku, however, is much more than a spectacle; it is a performing troupe presenting a unique form of Japanese dance - called Buto - that has stunned audiences across North America this summer and fall with its highly controlled, emotionally extreme, and dramatically riveting style. Created in the 1960s out of dissatisfaction with traditional Western and Japanese forms, Buto draws on these traditions to create a radically different vision of self-expression. Writes the company in its program: ''The white face of the Geisha (dancer, a traditional Japanese form) represents a being transfixed, but the whitened face of the Buto dancer is the moving face of humanity, actually in touch with innocence, wonder, fear, and mortality.''

It is this juxtaposition of antithetical feelings and ideas, exploring the very boundaries of human experience, that is the essence of Sankai Juku's form of Buto.

Take, for example, this scene from ''Kikkan Shonen,'' the company's first full-length production, which debuted in Tokyo in 1978. Ushio Amagatsu - founder and artistic director of the five-man company - enters the stage covered in a purple robe, appearing to be a midget (he is squatted down as he moves). He waddles about, smiling and laughing as he encounters different objects on the stage. Yet these simple facial expressions are so brilliantly and vividly portrayed that he quickly has the entire audience smiling and laughing with him.

But the joy lasts only moments. His smile turns to a grimace, laughter becomes hysteria. At one point, with some difficulty, he mounts a small platform. The audience cheers. Then, he falls off the edge flat onto his nose. A feeling of pain and loss pervades. But wait - the robe unravels, and his fall becomes a release, as the man fully extends himself and dances about the stage with glee.

Other scenes from ''Kikkan Shonen'' show four members of the company - again nearly naked and covered in white powder - swaying about sensually, sometimes erotically, to rock music that blasts gratingly through the speakers.

Often there is a darkness to Sankai Juku's performing that is unsettling - and intentionally so. At times in ''Kikkan Shonen'' the dancers take on inhuman forms, rolling about the stage like clay; at other times they seem to writhe in pain.

But just when these images are about to overwhelm an audience, the mood suddenly switches to silence and peace, and the dancers' movements change to something more ethereal, natural. At one point in ''Kikkan Shonen,'' Amagatsu dances with a fully grown peacock clasped in his arms. It is both beautiful and mysterious. At still another, dancers curl up in fetal-like positions and reach outward and upward, their hands and fingers unfurling with gentle control and powerful precision. It is all a display of control over the body and the emotions that has left many in awe.

This did not come about overnight. In an interview with The Christian Science Monitor through a translator, Amagatsu explained that his company was formed out of a Buto workshop that he held in 1975.

Thirty men and women started the workshop. Though Amagatsu refuses to reveal what Buto training involves, it is known that the mental and physical exercises are extremely demanding, sometimes almost brutal. By the workshop's close, only three men were left. Those three men - who had never trained in dance before - became the company. A fourth was added later.

For Keiji Morita, one member of the company, ''Peace is essential,'' when he dances, especially when doing the outdoor hangings. Another, Yoshiyuki Takada, says he thinks of his descents this way: ''If you're swimming 10 feet or 10,000 feet under the surface of the ocean, and you don't know, it doesn't matter.''

But beyond a few select comments, the members of Sankai Juku choose not to fully reveal their purposes or motives. It is an ambivalence that also marks their work.

Throughout ''Kikkan Shonen,'' images of birth and death, rebirth and deterioration seem to recur. But it would be hard to define any one scene's final meaning. ''Tension vs. the natural state is where it begins,'' says Amagatsu. Ultimately, though, he says, the audience's experience of a performance is completely subjective.

Of viewers' final response to Sankai Juku, though, there can be no mistaking. When the troupe came out for its bows here in Boston, the crowd leaped to its feet and cheered - but this was no ordinary ovation. The cheers were ones of almost childlike joy - whoops and yells. Indeed, this company - still relatively obscure in its home country - seems to have struck a deep chord, especially among young people, across North America this year.

Perhaps in its images of extreme fear and profound peace Sankai Juku is replicating essential elements of life in the nuclear age. Just like the scene at the entrance of the theater, life for many today seems to be filled with tensions and pressures. But then there are moments of joy and wonder at the achievements of our day.

In its often simple, sometimes dark, and ceaselessly ambivalent way, Sankai Juku has put our time to the looking glass, and we are amazed.