Of the four directional animals, only the Dark or Black Warrior (xuanwu) is in fact comprised of two animals, the snake entwined around the tortoise. The tortoise is viewed as a microcosm of the universe, its carapace representing heaven and its underbelly, the earth (see cat. nos. 14, 15). It is also associated with longevity, stability, and immortality. Its allusion to immortality harkens to the “Tangwen” chapter of the Liezi, which describes the five islands that lay in the eastern seas including the island of Penglai, the dwelling place of immortals. The islands were said to have lacked roots to keep them in place, and they therefore floated at the mercy of tide and wind. The immortals complained to the supreme power Di, who worried that they might be deprived of their homes. Di commanded Yu Jiang to dispatch fifteen giant tortoises to raise their heads and hold the islands in place. The tortoises in turn formed themselves into three teams, which rotated every 60,000 years.[1] In Chinese cosmology, tortoises are always female and must mate with snakes in order to procreate. By extension, their union represents the forces of the male yin and the female yang. This meaning of the Dark Warrior is supported by inscriptions on Han dynasty mirrors:

The fine copper which the Han dynasty possesses and which is drawn from Danyang and has been mixed with (silver and tin) and the mirror is pure and bright. The Dragon on the left and the Tiger on the right forfend all evil and keep the four quarters in order; the Scarlet Bird and the Dark Warrior accord with Yin and Yang.[2]

On our tomb tile, the snake weaves its sinuous body around that of the tortoise and appears ready to strike. Its underbelly is detailed with delicate ribbing, similar to that found on the other three directional animals shown in our exhibition, that highlights the curvature of its coiling form. The Dark Warrior continued to be used as a powerful cosmological symbol in tombs throughout the Six Dynasties period.[3]