Sequenza XI for solo guitar (1987–1988) is one of a series of Sequenzas by Luciano Berio. Written for the American guitarist Eliot Fisk, it is an innovative investigation into the dramatic and virtuosic possibilities of musical performance.
Form
The composition is in four large sections, and sets out from the six pitches of the open strings of the guitar. The composer asserted that two intervals are important elements in the work: the perfect fourth (which is the interval found between most neighbouring pairs of the guitar's strings) and the tritone, which leads to a different harmony of Berio's devising.[1]
Porcaro, Mark D. 2007. "A Polyphonic Type of Listening in and out of Focus: Berio’s Sequenza XI for Guitar". In Berio's Sequenzas: Essays on Performance, Composition, and Analysis, edited by Janet K. Halfyard, 255–274. Aldershot (Hants.); Burlington (Vermont): Ashgate Publishing. ISBN978-0-7546-5445-2.