Stephen Sondheim's 1976 genre-stretching musical poses real challenges for any revival, and although Gary Griffin's production stumbles occasionally, it does capture much of the work's excitement.

The show comes from Sondheim's near-operatic period, along with Sweeney Todd, and attempts nothing less than the epic story of Japan's 19th century opening to the West, as seen through Japanese eyes and presented in adaptations of Japanese theatrical and musical modes.

Along with book writers John Weidman and Hugh Wheeler, and original producer-director Harold Prince, Sondheim was pushing the Broadway musical to its very limits, and I can remember, on seeing the first production, how very exciting the first half-hour or so was, as we felt something new being done to an entertainment form that had fallen into the doldrums.

Unfortunately the excitement of that first production waned as the show went on and didn't quite succeed. Like almost all of Sondheim's shows, it had second act problems, and one left with the sense of seeing something almost happen, a promise that would have to wait for Sweeney Todd to be fulfilled.

Still, a not-quite-successful work of artistic ambition can be more satisfying than a show that aims for far less and easily achieves it. And though the current production solves some of the problems of the show while finding new ones, it is something any lover of musicals will want to see.

Griffin's biggest improvement lies in using his limits of budget and stage size wisely, turning the somewhat over-produced Broadway version into a pocket opera played out in the round with a cast of ten and an orchestra of four. Much of the show's charm, both musical and dramatic, lies in its delicate touches, which come across better in the Donmar's small space than they could in a large theatre.

Perhaps his biggest error is in not attempting, even within his budgetary boundaries, the respectful adaptation of Japanese performance styles that Hal Prince used. Instead, we get portrayals that are a little too panto-Japanese, with funny voices, elongated syllables and silly walks.

Aside from subverting the musical's attempt to make us see through Japanese eyes, this directorial decision interferes with some of the show's artistic vocabulary. To take one example, Commodore Perry, captain of the first American voyage to Japan, is seen by the play as a long-haired monster, the lion-god of Japanese dances. In the context of other Japanese styles treated respectfully, this was a powerful image of Japanese perception of the new, but in this revival it stands unexplained and ineffective.

Like all of Sondheim's songs (except for that clown-sending one), those in this show resist being taken out of their dramatic context. Still, the score does include Someone In A Tree, one of Sondheim's own favourites; the haunting Pretty Lady; and the only-he-could-have-written-all-those-clever-rhymes Chrysanthemum Tea.

With almost everyone in the cast playing at least a half-dozen roles each, Joseph Anthony Foronda is a strong presence as the narrator, while Kevin Gudahl holds our sympathy as the little man charged with dealing with the invaders.

If my experience in 1976 was of an exciting start fading away, this revival has the opposite effect, with a slow start gradually being energised by the inherent power of the music and the artistic ambition of the show.