Yin-Yang theory is a cosmology and methodology in China traditional culture, which has been fully reflected in the Book of Changes. It records many concepts about Yin and Yang, and regards Yin and Yang as the most basic reason for the change of everything in the universe.
The idea of harmony between man and nature is the origin of geomantic omen, the main body of China traditional culture and the guiding ideology of geomantic omen culture. It originated in the Spring and Autumn Period and the Warring States Period and matured in the Song Dynasty. The harmony between man and nature means that people should make the most effective use of the natural environment and seek the best natural conditions in order to achieve the realm of the integration of man and nature.
There is a short story about the origin of Feng Shui: It is said that Xuan Nv helped the Yellow Emperor defeat Chiyou in nine days, rescued the people from the war and gave him some books, including Feng Shui. Ancient things can't be verified now, so let's live in the present.