Gruppen

Gruppen is "a landmark in 20th-century music ... probably the first work of the post-war generation of composers in which technique and imagination combine on the highest level to produce an undisputable masterpiece".

Early in 1955 Stockhausen received a commission from WDR for a new orchestral composition, but his ongoing work on Gesang der Jünglinge prevented him from starting right away.

In August and September, he took the opportunity to retreat to an inexpensive rented room in the attic of a parsonage in Paspels, Switzerland, recommended to him by a colleague, Paul Gredinger.

[7] Upon returning to Cologne, Stockhausen resumed work on Gesang der Jünglinge and then composed the wind quintet Zeitmaße and Klavierstück XI, before turning to working-out the details of Gruppen, which occupied him for all of 1957.

[12] Consequently, the importance of individual notes is relatively low, so that sonority, density, speed, dynamics, and direction of movement become the main features for the listener.

[19] Because of the chord transformations that emerge between rehearsal numbers 118 and 120 it appears that Stockhausen was in fact aware of these properties, making it most likely that the relationship simply did not interest him compositionally.

However, because the resulting "fundamental durations" are not small enough for use in the musical detail, subdivisions corresponding to the transposition of the overtones of a pitch's harmonic spectrum are used.

[24] The composer recalled that, when Igor Stravinsky saw the score for the first time, he wrote that such fractional metronomic values as 63.5 and 113.5 were "a sign of German thoroughness".