Classical Chinese music theory combined tone and pitch to classify and name different types of music, as well as to describe their characteristics. The seven notes are known as gong (宫 corresponding to 1 in the numbered musical notation), shang (商 corresponding to 2), jue (角 corresponding to 3), bianzhi (变徵 corresponding to 4), zhi (徵 corresponding to 5), yu (羽 corresponding to 6) and biangong (变宫 corresponding to 7). Any one of them can be used as a major tune along with other notes set in particular intervals to form a mode. The mode with gong as the major note is called gong, the mode with the rest of the notes as major ones are called diao. The seven modes with the accompaniment of 12 temperaments can theoretically have 12 gongs and 72 diaos, altogether 84 modes of music. However, in practical music, not all the gongs and diaos were used. Only seven gongs with each having four tunes (all together 28 modes of music) were used for imperial court music in the Tang and Song dynasties. Seven gongs and 12 diaos were used for music to go along with poems in the Southern Song Dynasty. In the Yuan Dynasty, six gongs and 11 diaos were used for Northern music, and five gongs and four diaos were used for Southern music. In the Ming and Qing dynasties, only five gongs and four diaos were often used. Some music critics made rules for different gongs and diaos to be used for music for different occasions according to their characteristics. The theory of gongdiao played a role of direction and regulation in music creation for poems and operas and can be used to translate ancient music. It is an important subject for the study of ancient Chinese art

In The Book of Songs, “Major Court Hymns” are all in the gong mode, “Minor Court Hymns” all in the zhi mode, “Eulogies of Zhou” and “Eulogies of Lu” in the yu mode, and “Ballads” from the fifteen states all in the jue mode. Of all the works in The Book of Songs in the Zhou Dynasty, only “Eulogies of Shang,” altogether five pieces, use the shang mode.

(Zhu Zaiyu: A Collection of Writings on Music and Calendar)