The concept of Yin and Yang originated from the view of nature of ancient people in China. The ancients summed up the concept of yin and yang in a philosophical way by observing various opposing and related natural phenomena in nature, such as heaven and earth, sun and moon, day and night, cold and heat, men and women, up and down, etc. It is the objective law of nature, the origin of the movement and change of all things, and the basic law of human understanding of things.
Extended data:
Gankun is the beginning:
The preface to Zhouyi says that there is heaven and earth, and then everything comes into being. It means that with heaven and earth, everything can be made. In other words, heaven and earth are the mother of all things, and all things are generated by heaven and earth.
Because the dry hexagrams represent the sky and the Kun hexagrams represent the earth, it is equivalent to saying that the other 62 hexagrams represent everything, two dry hexagrams are the parents of the 64 hexagrams, and the other 62 hexagrams are all generated by the dry hexagrams. Therefore, the order of the sixty-four hexagrams in Zhouyi began with the two hexagrams of Gankun.
"Shuo Gua Chuan" said: It is also a dry day, so it is called the father; Kundi is also called mother; One person is killed by an earthquake, so it is called a long person; Xun got a daughter after a while, so she was called the eldest daughter; Kanso is a male, so he is called a male; Get another woman from the telegram, that's called a woman; Gen three got another man, so he was called a boy. A girl is called a girl because she got a girl after three requests.
That is to say, in the gossip, San Yao is the parents of other six Yao, and the other six Yao are all born by San Yao.
Baidu Encyclopedia-Yin and Yang (China Ancient Philosophy)
Baidu Encyclopedia-Gan Kun (Chinese vocabulary)