A fox-like creature whose head is white, said to be originating from a pre-histoical mammal.
Originally seen as an animal that can counter evil, it somehow became the synonym to comets which are seen as bad omen in ancient China.
In particular, the Tian Gou eating the Sun or the Moon is a common story passed down through folklore, which was how the ancient populace explained the phenomenon of sun or moon eclipses. During such times, the populace often rang gongs, played drums or even used firecrackers so as to ‘scare away’ the Tian Gou. Closely related to this story is the legend that when Chang E stole the immortal pills rewarded to her husband Hou Yi for shooting down nine Suns (and thus only leaving one sun in the sky), Hou Yi’s hunting hound chased her all through her ascent up to the sky. Hearing its bark, Chang E hid herself in the Moon. Meanwhile, all the hair on the hound’s body stood up erect and its body kept on expanding. Then in one motion, it leapt up and swallowed the Moon whole. When the Heavenly King and Queen heard about this event, they sent the Heavenly Guards to apprehend the black dog. When it was brought forth, the Heavenly Queen recognised it as Hou Yi’s hunting hound and gave it the title of Heavenly Dog and the responsibility of guarding the Southern Heavenly Door. As a result of the honour given to it, the hound spat out Chang E and the Moon. Thereafter, Change E made the Moon her home.
There is another story concerning how Chang Xian (an immortal in Chinese lore) shot the Heavenly Dog. In this story, the Heavenly Dog was obstructing the constellations from going to the mortal realm as children. When Chang Xian shot the Heavenly Dog and made it run away, the people were then able to get children and as a result, Chang Xian was known as “the children-giving Chang Xian”.