With this, the latest of his meditative, ritualistic chamber operas, Seattle composer Garrett Fisher seems to have reached a new level of theatrical sureness. The mystery in the Noh-influenced W.B. Yeats play on which the piece is based is heightened as three black-clad singers (one man, two women) switch among them the opera's two roles—Old Man and Young Man—by exchanging masks. Some of the text is in Japanese, some action takes place in shadowplay behind illuminated screens, and a prerecorded voice takes over at one point. The hawk of the title, guarding a well of immortality sought by the two Men, is played by dancer/choreographer Christy Fisher, with keenly observed birdlike movements.She, the singers, and Fisher's four-person orchestra are all billed together as the Fisher Ensemble and have built the piece collaboratively through improvisation on the leader's generative ideas. Yeats' Japanese inspiration is echoed here in the music: The flute evokes a shakuhachi, and the bass (a six-string fretted acoustic model, played by Greg Bagley) emulates the pitch-bending and silk-string purity of a koto—a funky koto with a subterranean low range. An array of percussion adds grit and atmosphere, while Fisher's harmonium wafts aural incense over it all.The wealth of attractive effects in the ensemble's previous opera, Psyche, never seemed to hang together as expertly; the elegantly distilled, 45-minute Well is more all-of-a-piece. Later this month, Fisher is taking the show to Boston and New York, and perhaps his plans to put Well in front of non-Seattleite audiences has helped him focus.