From the program notes of Yün, composed in 1969.
Yün (1969) “is based on the Chinese philosophic concept of art as the moment when ‘the universe and the individual merge as one’ (tien jen he yi). That is when macrocosm and microcosm resonate in sympathy,” Chou explains. “The title, Yün, is taken from the expression ‘ch’i yün,’ the foremost principle in Chinese art, which means reverberation (yün) of the revitalizing force in nature (ch’i).” This Taoist concept permeates the piece, which revels in the resonances of nature. Some of these resonances are audible and include “wind and thunder, rain drops and cascades, frogs and cicadas… ” Others are inaudible. The approach to listening is clarified in Chuang Tzu: “When it cannot be heard by the ear, listen with the mind, when it cannot be heard by the mind, listen through ch’i.”
|Slow and wide vibrato (no synchronization among parts).|
|Measured slow and wide vibrato with speed indicated (synchronization required).|
|Gradually and evenly change from non-vibrato to vibrato or vice versa.
If no vibrato is indicated, the use of normal vibrato is at the performer's discretion.
|Start the pitch around a semi-tone higher and lip down immediately, but smoothly, to the given pitch.|
|The opposite of the above, lipping up to the given pitch from below.|
|Lip to just above or below the neighboring semi-tone evenly throughout the duration of the note.|
|For flute and trombone, an even gliss. up or down about a semi-tone and back.|
|For flute, a slow trill on the given pitch with an alternate fingering.|
|Start the trill or tremolo very slowly with the indicated speed, then gradually and evenly increase the speed until a true trill or tremolo is arrived at the sign.|
|For tombone, gradually and evenly change the speed of the gliss. from one specified speed to the other.|
|Grace note or notes to be played on the beat (not before).|
|Grace notes to be played immediately after the attack of the measured note.|
|For percussion, a fast roll.|
|For percussion, gradually and evenly move from one specified location on the instrument to another.|
|For piano, stop the string very close to the agrafe.|
|For piano, stop the string lightly in the middle.|
|For piano, pluck the string with the fingernail very close to the agrafe.|