Each of the 20 unnumbered pages that make up John Cage’s Winter Music contains five systems notated on five bars. The systems are mostly divided into aggregates of notes or ‘events’, for which any number of pianists from one up to 20 can make their own programme of a specific time length, with complete freedom insofar as dynamics and resonances. The pages can be used in whole or in part.

As such, no two performances are alike, and it would be futile to judge Sabine Leibner’s solo piano realisation alongside any previous recordings. She divides the piece into four sections that total 67 minutes. You can’t determine by ear where a particular section ends and the next begins, because the performance mainly consists of slow-moving chords of varying density and dynamics. When a long silence ensues after a resonance dies out, one might think that the music has finished or that the playback device has been unplugged, but that’s not the case. These silences actually provoke a sense of anticipation of what comes next, which is as much a part of the experience as Liebner’s iteration of the actual notes.

Wergo’s exemplary engineering enhances the pianist’s pinpoint control of sonority, of voicing, of touch and of pedalling. These qualities readily reveal the seriousness, concentration and utter commitment that Liebner brings to the score. Suffice it to say that she does not approach Winter Music casually: the intensity and deliberation characterising her extraordinary recordings of Cage’s Etudes Australes (7/12) and Music for Piano 1 84 (Neos) and her gripping Morton Feldman late pieces (Oehms, 3/08) readily apply to this recommendable release.