For dramatic force, Joachim Herz's 1978 production of Madam Butterfly for Welsh National Opera has proved almost unbeatable. This revival is arguably the finest, with Nuccia Focile giving a remarkable performance in the title role.

Focile's husband, Paul Charles Clarke, plays the feckless Lieutenant Pinkerton and helps to invest their act-one duet with great intensity. But it is her partnership with conductor Carlo Rizzi that creates the emotional impact here.

What sets Cio-Cio-San apart from other geishas is her aspiration to a better life through marriage and her espousal of American values. Focile makes credible the transition from child bride - demurely flirtatious but terrified of being pinned like the butterflies after which she is named - to the tragic older figure.

The sense of a young woman who knows that she will ultimately bow to fate is even stronger. The moment when Cio-Cio-San admits that her most sacred possession is the knife with which her father took his life, suggesting a pact with death, is just the first of a succession of sharply focused moments plotted across the opera by Herz and beautifully executed by Focile and Rizzi.

The sepia tones and sliding screens of this set have lasted well; the production's most enduring image is that of Butterfly clinging to the screens, desperate for a glimpse of the returning Pinkerton, yet apparently caged by her own blind faith.

Focile's voice blazes with conviction: it is as if everything in her career thus far has led her to this point. Her ability to be delicate or imperious is matched note for note by Rizzi and the WNO orchestra, while the relationships with her servant, Suzuki (Anna Burford), and the go-between, Goro (Peter Hoare), are finely drawn. Pivotal to this performance is Christopher Purves as consul Sharpless, his dignity and humanity as palpable as Pinkerton's final remorse.

· In rep until March 9. Box office: 029-2087 8889. Then tours to Oxford, Birmingham, Southampton, and across Britain until July 6.