The six-part classification of books has become a four-part classification.

During the Spring and Autumn Period, Confucius compiled the literature into six arts, namely, poetry, calligraphy, Yi, ceremony, music and Spring and Autumn Period, that is, each category has its own book. Then in the Western Han Dynasty, Liu Xiang and his son compiled Seven Laws, which were divided into seven parts: Seven Laws, Six Artistic Laws, Zhuzi Law, Poetry Law, Military Law, Shu Shu Law and Ji Fang Law, among which Seven Laws was actually a general preface, so it could be temporarily called Liu Fenfa. However, literature,

The literature of history, Buddhist scriptures, Yin-Yang scholars and Five Elements scholars has increased, and this classification method can no longer meet the classification needs. During the reign of Emperor Wu of Jin, the secretary supervisor Xun Xu and the secretariat Zhang Hua arranged books, and they also collected bamboo books, so they imitated Wei Zhongjing.

Thin ",compiled into" new thin ". This classification has changed the original system, dividing the book into four parts: A, B, C and D. In the Annals of Sui Shu Classics compiled by the official in the early Tang Dynasty, it was named and classified by four subsets of classics and history for the first time, and the four parts were formally established.

The position of classification in ancient bibliography. Finally, when the Qing Dynasty edited the largest series of books in ancient China, it divided the abstracts of ancient books written in the editing process into four parts according to the subset of classics and history, and compiled the Catalogue of Siku Quanshu.

Want ". This is the establishment of the classification of classical and historical subsets.