The three-yuan dragon in Xuankong Feng Shui is used to arrange mountain disks and direction disks, which are divided into:
Northwest, the three mountains of Qian Gua: Diyuan Longxu, Tianyuan Longqian, Ren Yuan Longhai. Xushan Mountain belongs to Yin, and Qianhai Mountain belongs to Yang.
To the north, there are three mountains of Kan Gua: Diyuan Longren, Tianyuan Longzi, and Renyuan Longgui. Renshan Mountain belongs to Yang, and Zigui Mountain belongs to Yin.
In the northeast, there are three mountains of Gen Gua: Di Yuan Long Chou, Tian Yuan Long Gen, and Ren Yuan Long Yin. Chou Mountain belongs to Yin, and Genyin Mountain belongs to Yang.
Zhengdong, the three mountains of Zhen Gua: Diyuan Longjia, Tianyuan Longmao, and Renyuan Longyi. Mount Jia belongs to Yang, and Mount Mao and Yier belong to Yin.
In the southeast, there are three mountains of Xun Gua: Diyuan Longchen, Tianyuan Longxun, and Renyuan Longsi. Chenshan Mountain belongs to Yin, while Xunsi Mountain belongs to Yang.
To the south, there are three mountains of Li Gua: Di Yuan Long Bing, Tian Yuan Long Wu, and Ren Yuan Long Ding. Bingshan Mountain belongs to Yang, and Wudinger Mountain belongs to Yin.
In the southwest, there are three mountains of Kun Gua: Diyuan Longwei, Tianyuan Longkun, and Renyuan Longshen. Weishan Mountain belongs to Yin, and Kunshen Mountain belongs to Yang.
To the west, there are three mountains of Dui Gua: Di Yuan Long Geng, Tian Yuan Long You, and Ren Yuan Long Xin. Gengshan Mountain belongs to Yang, and Youxiner Mountain belongs to Yin.
Among them, the Yang dragon is arranged in a straight line in the trajectory of the nine palaces of Luoshu, and the Yin dragon is arranged in an inverse direction. Taking Yuan Yun as the territory and entering the nine palaces in order, it is called flying star. Taking the direction of the mountain as the pivot, dividing the yin and yang and then arranging them in a forward and reverse direction is called Daxing.