Kei Takei's epic dance work "Light" -- one of the seminal choreographic creations of the contemporary era -- has been evolving move by move, piece by piece, since 1969.

The two programs her troupe, Moving Earth, presented at Dance Place this past weekend under the label "Light -- A Retrospective," afforded an unusual opportunity to scan that evolution in the large. Embracing seven sections of "Light" ranging from Part 1 to the diptych formed by Parts 20 and 21, "Diary of the Dream" (1985), the back-to-back evenings revealed a growth pattern not unlike the metamorphosis of an embryo from a single cell to a complex, mature organism.

The overall direction of growth has clearly been from primal simplicity -- Part 1 employs just Takei and three women, all garbed in unadorned, peasantlike white togs, iterating basic moves, in silence, within a square of white tape -- to increasing degrees of structural, symbolic and theatrical complexity. "Diary of a Dream," which lasts about 40 minutes (about five times the length of Part 1) and calls for more than a dozen performers, involves chanting and speech, and props ranging from bright yellow umbrellas and coils of green rubber hose to large boxes wrapped in brown plastic and backpacks of black cloth.

Yet the parts of "Light" are separate and autonomous artistic entities, and the smaller, earlier pieces are not necessarily more limited in expressive reach or power than the later, longer, more elaborate ones, just as children are not invariably less interesting than adults. And though the scope of "Light" has been enlarging, its fundamental theme has remained the same -- the eternal human struggle for survival and enlightenment.

Some motifs have become constants for Takei. The backpacks of Parts 20 and 21 are precisely those of Part 1, and both are emblematic of the burdens of psychic and physical toil which are unvarying elements of the human condition, for every age and society. Others -- such as the challenge and blessing of nature -- recur in varying guise. Part 15, "The Second Windfield," depicts tribespeople buffeted by howling storms, staggering to keep their balance, and, in a final image at once droll and terrible, completely submerged beneath a canopy of sand, or rock, or despair, depending upon how you interpret the huge cloth drawn over them. In Part 18, "Wheat Fields," the community constructs a corral of logs and twigs, and violently hoes, churns and plows the earth within it.

Molded by Japanese tradition but strikingly original from the start, Takei's idiom -- using seemingly unschooled movements such as stomping, twisting, trudging and sagging; invoking the ritual force of repetition; and conceiving dance as a continuing spiritual quest -- has been enormously influential. Influence has run in the other direction, too -- components of contemporary western sensibility manifest themselves more and more in "Light," nowhere more conspicuously than in "Diary of the Dream," with its intentional self-questioning and self-mockery. "Doing the same old thing forever?" exclaims one of the dancers. "I want something new." "As usual," says another, addressing Takei, "you're not explaining anything to us -- what part is this we're doing, 20 or 21?"

If the character of "Light" has inevitably been changing -- how could a work whose genesis stretches across nearly two decades avert transformation -- so has the tenor of its performance. Today's Moving Earth dancers aren't those of 1969, with the exception of Takei, and in what we saw this weekend at Dance Place, only Takei retains the original, unself-conscious, raw spontaneity of the early days of "Light." The present troupe, though obviously fired with conviction about the piece, doesn't perform as if it's lived through this movement for years. Takei does the movements; the rest of the dancers show them. The performances have more the feel of a facsimile than of a distillation. The work -- its conception and shape and meaning -- is strong enough to transcend the external quality of its interpretation. But there is some sense of diminished impact, for those who've experienced past performances.

As part of the Dance Place's ambitious "Japan-America Dance Project," the "Light" retrospective will be repeated at Dance Place next weekend, complemented by several free, outdoor performances at other sites.