What is the Book of Changes?

One of China's earliest works on mathematics and astronomy. In ancient China, there were three kinds of astronomical theories according to different universe models, among which Gai Tian Shuo was one kind, and Zhouyi Tian Jing was the representative. The theory of this school holds that the sky is like a hat and the earth is like an overturned basin (the sky is like a hat and the earth is like an overturned basin). According to textual research, Zhou pian Shu Jing was written in the Western Han Dynasty (BC 1 century). The block-printed edition of Southern Song Dynasty (Jiading 6th year, 12 13) is the earliest block-printed edition handed down at present, and it is collected in Shanghai Library. Many mathematicians in the past dynasties have annotated this book, the most famous of which is the annotation by Feng Chun and others in the Tang Dynasty. The classic of parallel week calculation has also spread to South Korea and Japan, where there are also many inscriptions.