Sequenza XI

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 .
Usage.
"Sequenza XI" is a standard work for guitarists who have chosen avant-garde modern classical music as a part of their repertoire, e.g., Denis Sung-Hô ("Sequenza"'s performance with members of the Ensemble InterContemporain), Stefan Östersjö, Todd Seelye, Mats Scheidegger, Geoffrey Morris, Pablo Gómez, Pablo Márquez, Alan Thomas, Jürgen Ruck, Nico Couck, etc.: it has been recorded numerous times (see below).
"Chemins V" by Berio is a work by Berio based on "Sequenza XI", for guitar and ensemble.