Preview: Ensemble Tozai/LSO, St Luke's, London

The Japanese word "tozai", meaning "East-West", perfectly reflects the nature of this group, in which an Eastern taiko drum and shakuhachi flute balance a Western piano and violin. But what they will do here is firmly rooted in the East.

In addition to Akira Ifukube's violin sonata, and Graham Fitkin's improvised music for Japanese instruments, Gavin Bryars's Toru's Mist will get a new performance: this British composer's love of imperial Gagaku music is a very graceful tribute to Japan's traditional culture.

But the music that is likely to be the pièce de résistance of the evening will first be heard in short snatches in the intervals between the other works, before being performed in its entirety.

Its composer, Peter Wiegold (above), describes his style as "polymodal": "I like to set several worlds going at once, so that they clash. The piece will be stormy and dramatic, like a Japanese film noir. There will be the feeling of bells ringing in gardens, and water running. That's where I'm heading."

That's how he phrases it because, as we speak, the piece is not yet written - nor will it ever be, in full. He will create what he calls "cells" - melodies, harmonies, rhythmic patterns - and will induce the players to improvise around them.

"Though they can all read music, I want to approach it in a more person-to-person way, so that their own style comes through, rather than me trying to notate everything in my style. The piece will be shaped in performance."

Will the piece ever be "fixed" enough for other musicians to play it? "Elements will be fixed." Will it be published? "In part. I've been commissioning one-page scores from people, which players then develop creatively.

"This too will be published as a one-page score, which will have to be creatively realised each time it's performed." Wouldn't it be better to e-mail it than formally publish it? "Definitely. I love e-mailing scores."

(020-7638 8891; www.lso.co.uk), 4 March