Kraanerg is a composition for 23 instruments and 4-channel analog tape composed by Iannis Xenakis in 1968, as ballet, with choreography by Roland Petit and set design by Victor Vasarely.
[1] The title, by Xenakis, is an imaginary compound of the Greek-originating stems kraan (κρααν) and erg (εργ), meaning accomplished action.
According to the composer's program note, the title also refers to the "current youth movements" of that time, and his vision of the imminent "biological struggle between generations unfurling all over the planet, destroying existing political, social, urban, scientific, artistic, and ideological frameworks on a scale never before attempted by humanity."
[1] The 75-minute composition is not divided into movements but includes twenty-two periods of silence of varying lengths (three of them more than twenty seconds) which are integral to the work's development.
After a tour of the original ballet that ended in 1972, Kraanerg was largely forgotten until 1988 when a new choreography was created the Australian choreographer Graeme Murphy with Roger Woodward directing twenty-five performances at the Sydney Opera House.