Twelve-tone technique

A technique of composing with reference to all twelve notes of the chromatic scale which are ordered into series (also called tone row). Each note appears in the series only once. 

Also Twelve-note composition, Dodecaphony

A technique of composing with reference to all twelve notes of the chromatic scale which are ordered into series (also called tone row). Each note appears in the series only once. While the series may be used in musical composition in four forms (prime, retrograde – notes of the prime form are ordered from last to first, inversion – intervals between notes are reversed in direction, this is e.g. that descending major third in the prime form becomes ascending major third in the inversion, and retrograde inversion). Each of these may be transposed to any level of the chromatic scale, so that there are 48 forms of the series available. The technique was invented by Arnold Schoenberg (1874–1951) in the middle of the 1920s and described by himself as a “method of composing with twelve tones related only with one another”. Over time, the technique began to be used by many composers in Europe and the USA.