At a recent National theatre event, Harold Pinter lambasted the "millions of totally deluded American people" for not resisting the Bush administration's warmongering. A visit to the Donmar/Chicago Shakespeare Theater co-production of Pacific Overtures, featuring music and lyrics by Stephen Sondheim, book by John Weidman and additional material by Hugh Wheeler, might persuade the old curmudgeon that some of the best critics of American economic and cultural imperialism are the Americans themselves. For this is a beautifully told - and sung - tale of of Japan's transition from closed-off feudal society, isolated from the rest of the world for over 250 years by order of the Shoguns, to the frenetically-paced, industrial giant of today - following the arrival of four US warships in Uraga harbour in 1853, forcing the nation to open up trade with, first America, then the rest of the West.

First produced on Broadway in 1976, the musical is also fascinating for its experiments in form, progressing from the stately minimalist style of Noh to the barnstorming antics of American musical theatre, by way of Kabuki, Bunkaru - even Gilbert and Sullivan. In Gary Griffin's all-male, in-the-round production, a plain wooden stage is overhung by a battery of percussion instruments, highlighting the wit of Sondheim's score where the sound of an American ship's bell can, in contrast to the soft chimes of an Oriental gong, send a whole nation into a frenzy of panic.

Among a uniformly excellent cast, Kevin Gudahl's gorgeous baritone lends weight to his role as the samurai charged with ensuring that the foreign intruders do not set foot on sacred soil. He is well matched by Richard Henders as the lowly fisherman who helps him succeed - on the first visit. Joseph Anthony Foronda, meanwhile, is a strong, charismatic narrator, while Jerome Pradon excels in the comedic roles of the Shogun's Mother and a French Admiral.

But Sondheim's star shines brightest, his luscious songs intricate mini dramas in themselves. "Pretty Lady" conveys the fear of an uncomprehending Japanese girl as well as the desperate yearning of the rough British sailors trying to chart her up - with terrible consequences. Meanwhile, "Someone in a Tree" thrusts the little people to the forefront of history as a boy watches the Kanagawa Treaty being brokered from a tree, unable to hear, and a guard listens in, unable to see. All parties take away different versions of events - further confused by disagreements between the boy's older and younger selves. Even Pinter might struggle to write a scene juggling that many dramatic elements.