Here, bi (比) means to arrange and combine something in a certain way, and yue(乐) means to express through music. As a noun in its broad sense, yue refers to both the arrangement of sounds and the dance that accompanies the music. When a person experiences changes of feeling, triggered by external encounter, he will naturally make a variety of sounds. Simple and invariable, these sounds can be converted into tonic notes, or yin (音), such as gong (宫, corresponding roughly to 1 in the numbered musical notation), shang (商, corresponding to 2 ), jue (角, corresponding to 3 ), zhi (徵, corresponding to 5 ), and yu (羽, corresponding to 6 ), because of their differences in pitch, length, and speed. These notes are thus arranged and combined into a piece of music, or yue in a certain way. This quotation is an ancient Chinese theory on the origin of music.

All musical notes arise from the mind, and one’s mental activities are caused by external things. Activities that derive from thoughts on things are expressed in sounds. Changes are produced when those sounds respond to one another. When tunes are made according to such changes, the sounds are converted into musical notes. The arrangement of notes, together with dancing with shields, axes, plumes, and oxtails, creates a musical piece. (The Book of Rites)

In the twelve-tone temperament, the interval between the scales of huangzhong and dalü or between dalü and taicu constitutes a semitone, which forms a specific pitch. The interval between huangzhong and taicu or between taicu and guxian constitutes a whole tone, which also forms a specific pitch. Therefore, the concept “arrange notes into a piece of music” in The Book of Rites tells us the musicological rule. (Zhang Deying: Verifications on Ci Poems)