A development of the phasing technique from Reich's earlier works such as Piano Phase, it was written when Reich wanted to (in his own words) "create a piece of music that needed no instruments beyond the human body". However, he quickly found that the mechanism of phasing slowly in and out of tempo with each other was inappropriate for the simple clapping involved in producing the actual sounds that made the music.
Instead of phasing, one performer claps a basic rhythm, a variation of the fundamental African bell pattern in 12/8 time, for the entirety of the piece. The other claps the same pattern, but after every 8 or 12 bars shifts by one eighth note to the right. The two performers continue this until the second performer has shifted 12 eighth notes and is hence playing the pattern in unison with the first performer again (as at the beginning), some 144 bars later. The variation of the African bell pattern is minimal; it contains just one additional beat. However, this minimal addition results in a much more interesting piece from the point of view of the variation of syncopation as the piece progresses.
In 2012 an authorized arrangement for solo piano of Clapping Music was released on the album Which Way Is Up? by Simon Rackham, with permission granted by the publisher Universal Edition (London).
- Justin Colannino, Francisco Gomez, and Godfried T. Toussaint, "Analysis of emergent beat-class sets in Steve Reich's Clapping Music and the Yoruba bell timeline," Perspectives of New Music, April 2009.
- Reich, S. (1974). Pendlum Music. In Writings about Music (pp. 12–13). The Press of the Nova Scotia College of Art and Design (Co-published by: New York University Press). ISBN 0-919616-02-X