The full name of Six Codes of the Tang Dynasty is Six Codes of the Great Tang Dynasty, which is an administrative code of the Tang Dynasty. This is the earliest existing administrative code in China. When Tang Xuanzong was an official, the old title was written by Tang Xuanzong and noted by Li. It was actually compiled by Zhang Shuo and Zhang Jiuling and was written in the 26th year of Kaiyuan (738). It is the earliest existing canon, and the official system originated from the early Tang Dynasty to Kaiyuan. The name of Six Codes comes from Zhou Li, which originally refers to governing codes, teaching codes, ritual codes, political codes, criminal codes and event codes. Later generations set up six books here. This encyclopedia has more details.
The Grand Ceremony of Tang Kaiyuan was written by Tang Kaiyuan, with volume 150. Etiquette was not customized in the early Tang Dynasty, but was temporarily agreed. During the Kaiyuan period, Zhang Shuo appeared, Guan Zhen and Shu were selected, and the similarities and differences were compromised. Founded by Xu Jian and completed by Xiao Song, it was promulgated in the 20th year of Kaiyuan (AD 732). The title of The Grand Ceremony of Tang Kaiyuan is divided into five ceremonies: Ji Li, Ke Li, Xi Li, Military Li and Fierce Li. Du You once took a part of it and put it in Tongdian and New and Old Tang Books? Li Zhi is also based on this.
Online information, hope to adopt.