Music theory - Gakuri

...At first, there were four dancers, but by the end of the Warring States period, the Rokukei dance with 12 dancers appeared. The five-tone, seven-tone, and twelve-tone musical theories were gradually established, and a full range of ancient gagaku instruments, such as the koto (koto), shitsu (setsu), bell (sho), kei (kei), pipe, yaku (yaku), sho (sho), chi (chi), ken (ken), fu (kan), shuyuku (shuyuku), giyo (giyo), drum, tianzhong (tianzhong), and tianqing (tianqing), were available. These instruments were classified into eight tones (gold, stone, earth, leather, thread, wood, hou (hou), and bamboo) according to the material they were made of. In the Han dynasty (206 BC-220 AD), the state, based on the idea of ​​ritual music, attempted to establish a system of gagaku as part of its governing policy.

*Some of the terminology that refers to "music theory" is listed below.

Source | Heibonsha World Encyclopedia 2nd Edition | Information

…舞人ははじめ4人であったが，戦国時代末には12人の六佾の舞が現れた。五声，七声，十二律の音楽理論もしだいに整い，琴（きん），瑟（しつ），鐘（しよう），磬（けい），管，籥（やく），笙（しよう），篪（ち），壎（けん），缶（ふ），柷（しゆく），敔（ぎよ），鼓，編鐘，編磬などの古代雅楽器もひととおりそろい，これらの楽器は材質によって八音（はちおん）(金，石，土，革，糸，木，匏（ほう），竹)に分類された。漢代(前206‐後220)に至り，礼楽思想のもとに国家は統治政策の一端として雅楽の制度確立をはかった。…

※「楽理」について言及している用語解説の一部を掲載しています。

出典｜株式会社平凡社世界大百科事典 第２版について | 情報