Qinglong was originally the God of the East in ancient mythology, and one of the Seven Hosts and Four Elephants in the East in Taoism. Twenty-eight lodging houses, and seven lodging houses in the East (Jiao, Kang, Bian, Fang, Xin, Wei and Fan) have the image of dragons, which are located in the East, belong to wood and are blue in color, collectively called Qinglong, also known as Black Dragon. The forty-four volumes of Taizhi call Qinglong Dongdou as follows: "Jiao Su Tianmen, Kang Su Ting, Chang Su Tianfu, Su Fang Tian Yi Xing Jun, Xin Su Uranus Jun, Wei Su Tian Ji Xing Jun, Ji Su Tian Lu Xing Jun." As for its image, there are seven clouds in The Collection of Doors and Tongjiao: "Oriental Dragon Horn, full of air, spits clouds and glows, thunders, flies to octupole, walks around four ghosts and stands on my left. In addition, Taoism also uses it in alchemy. For example, Volume 72 of "Seven Chapters of Clouds" quotes the Dan of the four ancient gods, saying: The dragon is a dragon, and the oriental wood is also mercury. It is clear and unwilling, not turbid, not desirable, far away, and infinitely hidden, so it is called dragon.
The white tiger was originally the western god in ancient mythology, and it was one of the four images of the seven Pleiades in Taoism. The seven western lodgings (Kui, Lou, Stomach, Ang, Bi, tapir and Shen) in the twenty-eight lodgings are elephant tigers, located in the west, belonging to gold and white in color, which are collectively called white tigers. The emperor's father is like a vegetarian. Volume 44 says that the White Tiger Xi fights Xing Jun: "Xing Jun, a heavenly general in Su Kui, Xing Jun in Lousu Tiancang, Xing Jun in Suwei Tiancang, Xing Jun in Angsu Tianmu, a two-star gentleman in Bi Sutian, a star gentleman in Li Su Tianping, and a star gentleman in Shen Su Tianshui." As for its image, there are seven clouds in the book "Collection of Daomen Tongjiao": "The West should be a tiger, with the quality of Yingying, and the tone should be fixed. At the same time, Taoism also uses it in alchemy. For example, Volume 72 of Yun Qi Tanabata quoted the Dan of the Four Gods in ancient books and said: "White tiger, western gold, also get a real position." "Jing" says: if a son succeeds, his wife's synonym and five elements are born together, which is also caused by essence. It can't move, so it's called a tiger.