Literal translation: "(to) co-ordinate / co-operate"; Thrasher, who translates it as "cooperation" [sic], defines it as a "system of producing harmonizing pitch clusters", informing us that "In practice, each Zhǔyīn (主音 [root tone; i.e. keynote / tonic; ws])* of a melody is performed with a Péiyīn (陪音 [accompanying tone])* a perfect fifth above it. Owing to the instrument’s narrow [i.e. limited; ws] range, some accompanying tones are instead played a fourth below, and octave pitches are often added as well. The tonal position of ti [the 7th step in the scale], which is used infrequently, is usually sounded alone (Gao 1959:58ff, Xu 1991). […] The peihe system of the Fāng shēng is more simple than that of the Xiǎoshēng, utilizing perfect fifths but no octaves or unison doublings" [and] "The peihe system for the Yuán shēng is thicker than that of the Xiaosheng, using lower perfect fourths, as well as upper perfect fifths and octaves in accompaniment".

Dānyīn, Héxián