Wu Gang
Wu Gang, formerly romanized as Wu Kang and also known as Wu Zhi in some sources, is a figure in traditional Chinese folklore and religion. He is known for endlessly cutting down a self-healing osmanthus tree on the Moon, a divine punishment which has led to his description as the Chinese Sisyphus. In modern Chinese, the chengyu "Wu Gang chopping the tree" is used to describe any endless toil. The specific reason for his situation has varied in the sources, but Wu Gang's story dates back to at least the Tang dynasty.
Legend
Origins
An origin myth for the lunar phases was that a great forest or great tree grew there, swiftly growing and losing leaves and blossoms over the course of each month. After the expansion of the Chinese cultural area south of the Yangtze during the Qin and Han dynasties, the lunar trees became associated with the fragrant and white-blossoming Osmanthus fragrans. This tree flowers during the autumn and promoted the connection of the harvest festival with the Moon, a connection still observed during the modern Mid-Autumn Festival. Confections and cassia wine flavored with its blossoms are also still associated with the holiday.By the time of the Han, the Huainanzi associated the waxing of the moon with trees growing from the feet of a Daoist immortal.
In his Compendium of Materia Medica, Li Shizhen explains that Wu Gang was added to the stories about the holiday from novellas published during the Sui and Tang dynasties.