1, Jing: refers to Confucian classics; For example, The Analects of Confucius and Mencius.
2, history: history books, that is, official history; Such as twenty-four histories.
3. Zi: Hundreds of works in the pre-Qin period, religion; For example, everything is wrong, guiguzi and so on.
4, set: selected books, that is, poetry collections. Generally refers to the ancient classics of China. Such as Chuci, Daojing, Buddhist scriptures, etc.
The subset of classics and history refers to these.