Opérations booléennes pour «Herma»
Herma (1961) for piano was Xenakis's first composition for a solo instrument. It was commissioned in 1961 by pianist and composer Yuji Takahashi, whom Xenakis met on a trip to Japan in April of that year. The Greek title may be translated as «bond», but also as «foundation» or «embryo», and perhaps reflects an intuition on the composer's part that this was to be a seminal work insofar as it was his first departure from purely stochastic means of composition.
This technically very difficult piece makes unprecedented demands upon the performer, who must play complex rhythmic figures involving huge leaps with perfect evenness of articulation. In a good performance, the effort is repaid by the creation of a sense of seething, amorphous energy and a powerful forward momentum. The experience is unlike that associated with any prior piece in the piano literature. The ear strains to absorb it, but does not succumb to
frustration or numbness. The frenzied sonic activity maintains a surprising sense of perceptual lucidity, never becoming muddy.
The composer himself provides a detailed theoretical discussion of Herma's construction in his book, Formalized Music. Referring to Herma as an example of «Symbolic Music,» Xenakis advances a model of the piece which involves the exemplification of specific mathematical relationships between certain pitch sets. The macro-structure of the composition is clearly outlined as well. Details regarding the specific pitch and rhythmic choices made are not included, however, and, while the composer makes indications of what ought to be listened for in the piece, a typical listening unavoidably raises certain questions which the composer does not address regarding what actually is heard. In particular, the ability of listeners to recognize the proposed model in the music, and the ability of the model to account for important aspects of the music as heard, both beg examination.
Society for Music Theory
