The sonata for solo 'cello marked the arrival of a new level of compositional thought for the composer along with his 'dialogues' for 2 pianos and orchestra (1965)

This mature phase may be termed Zimmermann's 'pluralistic' compositional style where the music combines metrical structures with those based around 'suspended' rhythms.

For Zimmermann it is where objective time meets subjective time. For the listener the result is a college of sounds which seem to emerge from the familiar 'cello repertoire but are now used to extend into the unknown.

Zimmermann presents the performer with a piece as Gabriel Prynn remarks: "reaches the limit of what is possible in a Classical framework" Also as the 'cellist Thomas Demenga says: "the exchange and interpenetration of many time layers" poses real problems for the interpreter.

Zimmermann however is fearless of the bounderies of technique as Michael Gielen says in a preface to a list of his work (published by Schott, click here for more information)

"his imagination was always a little bit in advance of the current standard of performance, and he could not understand that this meant that in the first performance we interpreters could only offer an approximation of his work"

The compositional ideas of this work are continued in the second Act of his opera 'Die Soldaten', begun in 1957 and not completed 1965.The composer viewed his works as a continued line of thought and therefore saw no problem in breaking off and resuming projects.

There is a interesting link here with Pierre Boulez who also famously reworks his music.

The sonata for 'cello is one of three extremely compressed pieces for solo instruments,(the others for viola and violin) which he described as works of solitude, stillness and pure musical thought stripped of superficiality."

Zimmermann's conception of "stillness" differs from the Cage notion of the blank space in pages of Winter music as 'an absence of events', and the importance of Stillness in the piece to hear harmonics created etc.

Another notion of 'stillness' may be found in the near silences of psychic music ll which have a functionality; to allow the mind to anticipate the musical sounds to follow etc.