Myth of the Moon Toad

The Chinese belief concerning a toad in the moon predates the Warring States era.¹ Late Warring States era statesman and poet Qu Yuan (340-278 BCE) wrote of a toad in the moon in his Songs of Chu.²

Moon Toad may predate other Chinese moon myths such as the Moon Hare.¹ One version of the Moon Toad myth claims that the toad is the lady Chang E (aka Heng E) transformed. Imperial Readings of the Taiping Era (written between 977 and 983 CE³) quotes earlier works that mention a moon toad, including the astronomy book Ling Xian by Zhang Heng (78-139 CE)⁴:

Yi asked the Queen Mother of the West for the Medicine of Immortality. Yi's wife Heng E stole the medicine and flew to the moon. She installed herself on the moon and became a toad.

A fuller version of the tale is presented on Chang E on Baidu Encyclopedia and in the Shan Hai Jing, paraphrased in translation below:

Once 10 suns roamed the skies and parched the earth. The immortal archer Yi shot down 9 of the suns, much to the relief of the mortals on Earth. But the 9 suns that Yi killed were sons of the Heavenly Emperor. As a result, Yi and his wife Chang E (who may be a daughter of the Heavenly Emperor) were banished to Earth to live as mortals.

On Earth, Yi undertook a perilous journey to see the Queen Mother of the West, a goddess who possessed the Medicine of Immortality. The Queen Mother of the West had only one pill left, which she gave to Yi, telling him that one pill was a sufficient dose for two people.

Yi returned to his wife. They agreed to consume the medicine together on their wedding anniversary. But one day, when Yi was out hunting, Chang E could not resist the lure of immortality and ate all the medicine. She floated towards the heavens, but fearing to return to the Heavenly Court, she decided to go to the moon palace. There, living through long ages of regret and solitude, she changed into a toad.

Anyway, there are many versions of the Chang E myth, and this is just one of them. Han Dynasty sources typically depict Lady Chang E as a human who changed into a toad, though storytellers from later periods tended to romanticize the myth by omitting the toad transformation.⁵

Notes:

1. Frog Lore Section 6
2. 'Tian Wen' from Songs of Chu
   Qu Yuan on Wikisource
   
3. Imperial Readings of the Taiping Era on Baidu Encyclopedia
4. Book 4 of Imperial Readings of the Taiping Era
   Ling Xian on Baidu Encylopedia
   
5. Chang E on Baidu Encyclopedia