Three artists, in a way, share the title role in Kocho, the latest dreamy, poetic, subtly perfumed dance/opera by Garrett Fisher. His sister/frequent collaborator Christy Fisher (pictured) portrays a butterfly, as does one of the cast of five singers and, metaphorically, the flutist in the four-instrument orchestra (the other three: an array of gongs, a six-string bass, and Fisher himself on harmonium). Fisher took his text, sung in Japanese, from a 15th-century Noh drama; it enfolds a central interlude of new poetry in modern English by Amy Schrader. Meditative, ritualistic, and always eschewing traditional operatic melodrama for gentle, even inscrutable, lyricism, Fisher's operas have gained a following on both coasts; in September he'll take Kocho to New York, where Times critic Steve Smith called last year's Yeats-based At the Hawk's Well a "strikingly individual utterance of unambiguous beauty." To open this evening, pianist Byron Schenkman will play Fisher's Piano Raga no. 1, a piece which combines Fisher's interest in Indian-style improvisational structures and Schenkman's vivid way with the rhapsodic freedom of 16th-century keyboard music, the repertory he's more usually associated with.