The concept of the four gods, also referred to as the four symbols (四象), originates from ancient Chinese astronomy. Astronomers believed there are 28 mansions or constellations spread out along the sky. They divided the sky into four quadrants – north, south, east and west, each containing 7 of the mansions, and with a divine creature ruling each quadrants. These creatures are known as the four gods: the azure dragon, vermillion bird, white tiger and black turtle. 

This belief was imported to Japan and absorbed into the school of Onmyoudo, where they use celestial movements for divination.

The azure dragon (青龍) is to the east. A dragon, quite obviously, of a greenish-blue color that represents nature and the fresh breath of spring.

The vermillion bird (朱雀) (not to be confused with the phoenix) is to the south. The red color represents the sun and fire, and the summer of nature’s growth.

The white tiger (白虎) is to the west. The white color represents metal and grain, and symbolizes reaping the riches of the fall season when nature ripens to fruition.

The black turtle (玄武) is to the north. Though translated to ‘turtle’ or ‘tortoise’, this creature is depicted as a turtle intertwined with a snake. It stems from ancient Chinese belief that turtles had no male species and had to accept the snake’s ‘spirit’ in order to reproduce – hence the depiction, which seems a little blatant when put that way. The black color also symbolises cold water and death, as well as the night, representing winter’s death and the burgeoning of new life. The black turtle is also believed to govern life and death, as it is said in Taoism that souls of the dead will gather in the north.

Source: 日本神妖博物誌 作者： 多田克己 譯者：歐凱寧