2.1 American Development

In 1950, the New York school of composers (John Cage, Morton Feldman, Earle Brown, and Christian Wolff) began developing new forms of notation. The central category of this form of notation is indeterminacy, through which the composer grants the performer improvisatory latitude.^[5] Morton Feldman’s composition Projection 1 (1950) in graph (paper) notation is indetermined with respect to its pitch. Feldman does, however, prescribe three different registers and thus a framework within which the performer has to choose the pitch.

John Cage’s performance material Cartridge Music (1960) is also indetermined, as are several of the compositions in the Variations series (1958–1967), which consists of various printed transparencies that the performer can lay over one another in a new way for each performance and interpret according to Cage’s instructions. The resulting values often specify actions and not sounding results. In his Concert for Piano and Orchestra (1958), Cage assembles a compendium of different notations for the piano solo part.

Earle Brown’s December 1952 from the Folio series is regarded as the first graphic music. Instrumentation, pitch, and rhythm, as well as the reading order and turning of the page, are indetermined. By using these types of graphics, the composer Brown, who was interested in jazz, wanted to motivate the performers to improvise.^[6] Whereas Brown aimed at improvisation with the spontaneous translation of the visual impression, Feldman and Cage avoided the term improvisation and demanded the detailed elaboration and planning of each performance.

In the 1950s, compositions by the New York school of composers were primarily played by David Tudor (1926–1996), one of the leading performers of contemporary music for piano. He realized the indetermined pieces by devising a playing score: he laid down all of the decisions to be made by the performer in a rehearsal phase and put them in writing.

Between 1956 and 1962, Tudor performed at the Darmstädter Ferienkurse für Neue Musik (Darmstadt New Music Summer School). Numerous European composers wrote works specifically for him. In 1959, Sylvano Bussotti wrote the following about his Five Piano Pieces for David Tudor: The expression ‘for David Tudor’ in the title is not a dedication but almost designates an instrumentation. […] In many cases, the acoustic event that such graphics may trigger remains in the pianist’s hands.^[7]