There are many processes for studying the "Book of Changes", which can generally be classified into two schools, the "Xiangshu School" and the "Giri School".
Xiangshu School
Xiangshu are originally separate, but are used together in Yi Xue.
"Xiang" refers to the shape, also known as "Yi Xiang".
"Zhouyi. Xici Zhuan" believes that Bagua is made by looking up at astronomical images, looking down at geographical images, taking the images of the human body up close, and taking the images of things far away. The traditional view is that the images in the "Book of Changes" have three meanings:
First, the shapes of the eight trigrams, the sixty-four hexagrams and the three hundred and eighty-four hexagrams, that is, the hexagram image and the line image. For example, the image of the Ding hexagram is like a "ding", the lower line is like the legs of the tripod, the fifth line is like the ears of the tripod, the upper line is like the bars of the tripod, and the three middle lines are like the belly of the tripod.
Second, the things symbolized by the Bagua, such as Qian as heaven and father, Kun as earth as mother, etc.
Third, the specific things mentioned in the hexagrams and linea, such as the dragon in the Qian hexagram and the female horse in the Kun hexagram.
"Number" refers to number and calculation, also known as "easy number". Yi numbers also have three meanings:
1. The number of attributes of each hexagram and line, namely six, seven, eight, and nine. Seven and nine represent odd numbers and represent Yang, while six and eight are even numbers and represent Yin.
2. The numbers in the order of Yao are the first, second, third, fourth, fifth and top, which is the changing pattern of Yao.
3. During the divination process, the required hexagrams are derived based on the calculation of the number of shī grass.
Yi Li School
"Yi" means meaning, and "Li" means truth. The Yili School pays attention to the meaning and truth contained in the hexagram names, hexagram lines and hexagram images in the "Book of Changes", and explains it from the perspective of abstract virtues, functions, attributes and meanings.
Xiangshu and meaning can be regarded as two sides of the same thing. For example, Qian has the meaning of health, because Qian resembles the sky, and the movement patterns of celestial bodies are repeated, uninterrupted, and powerful, which just shows the attribute of health.