In October 1967 flautist Petr Kotik’s QUaX Ensemble gave a performance of Cornelius Cardew’s graphic-score masterwork Treatise in Prague and, happily for us, someone thought to record it. Now Kotik and Mode Records boss Brian Brandt have remastered this precious piece of history and it sounds very good indeed: febrile, expansive, itchy with life.

Treatise was Cardew’s most trail-blazing moment, a source of boundless ideas, controversies and rethinks. On the page his 193-leaf graphic score is a beautiful thing that makes you fall, Alice-like, towards sound. Running throughout is an empty stave (broken only exceptionally), above which Cardew’s intricate calligraphy has circles rotating inside circles, masses of fractal-like linear activity, lunar landscape shapes and pulverised conventional notation that has disembodied notes and accidentals melting against abstract graphics. Appropriately for a composer who had recently migrated from Stockhausen’s overbearing control to join free-improvisation collective AMM, these symbols don’t come with a definitive codebook. To each player they mean whatever they mean.

Unlike the performers on Art Lange’s overly practised, slick 1999 version (hatART), these players often – and quite obviously – have no idea what should come next, and busy silences punctuate as they intuit how to move forwards. Sometimes they land themselves in a cul-de-sac; more often they jump with an ecstatic leap of collective faith towards bold new freedoms. It would be easy to lampoon the period trimmings: the bouncing ping-pong balls, a trumpet played with a bassoon reed, everyone doubling on violin whether they play violin or not. But every note is sincerity felt, every sound pursued to a beautiful, authentic core.