The following is extracted from a note by the composer:
Phrygian Gates and its little companion piece, China Gates, are products of a critical period in my career as a composer. Together they comprise what could be my "opus one" by virtue of the fact that they appeared in 1977-78 as the first coherent statements in a new language. Several earlier pieces from the 1970s - American Standard, Grounding and some tape compositions - seem in retrospect to be inventive but still searching for a means of holding themselves together.
Phrygian Gates shows a strong influence of Minimalist procedures, and it is for sure the first piece of mine to be based on the idea of repetitive cell structure.… I found the combination of tonality, pulsation, and large architectonic structures to be extremely promising.
Phrygian Gates shows in as clear a way as possible how I approached these potentials of Minimalism. Phrygian Gates is a 22-minute tour of half of the cycle of keys, modulating by the circle of fifths rather than stepwise à la Well-Tempered Clavier. The structure is in the form of a modulating square wave with one state in the Lydian mode and the other in the Phrygian mode.… "Gates," a term borrowed from electronics, are the moments when the modes abruptly and without warning shift. There is "mode" in this music, but there is no "modulation."
Phrygian Gates is a behemoth of sorts and requires a pianist capable of considerable physical endurance and with an ability to sustain long arches of sound. China Gates, on the other hand, was written for young pianists and utilizes the same principles without resorting to virtuoso technical effects. It too oscillates between two modal worlds, only it does so with extreme delicacy. It strikes me now as a piece calling for real attention to details of dark, light, and the shadows that exist between.