In ancient times, only Sifang, post-Xuanwu, former Suzaku, Zuo Qinglong and Right White Tiger were discussed.
After the invention of Tugui, the twelve directions, that is, the congenital twelve branches: Zi, Ugly, Yin, Mao, Chen, Si, Wu, Wei, Shen, You, Xu and Hai, are also called the twelve mountain directions, and one mountain direction accounts for 30 degrees.
Eight schools of thought prevailed in Han dynasty, and eight schools used gossip to show their position.
At the end of the Tang Dynasty, Yang Junsong, a Buddhist, improved the geomantic compass, combining the three systems of heavenly stems and earthly branches's Eight Diagrams, and divided the azimuth into twenty-four mountain directions, each of which accounted for 15 degrees. That is, the north is not United, the son and the decyl, the ugly in the northeast, the gen and the yin, the Oriental armour, the Mao and the B, the southeast Chen, Xun and Si, the south C, the afternoon and the Ding, the southwest Wei, Kun and Shen, the west Geng, the unitary and the Xin, the northwest Xu, the dry and the sea.
The direction of the Twenty-four Mountains is the basic direction of Feng Shui.
At the foot of the Twenty-four Mountains, each distribution style further subdivides its positions according to its own needs.
There are seventy-two dragons, sixty dragons, one hundred and twenty dragons, two hundred and forty dragons and so on.
Sixty-four hexagrams, 384 levels.