Wu Gang Chops the Laurel
According to the Book of the Master of Huainan ( 《淮南子》 Huainanzi ), there were immortals and laurels on the moon. It was said that when the moon waxes, its size grows, from a foot of an immortal to a laurel. In the Tang dynasty, the story had another version, which was recorded in the chapter Heavenly Principle of Miscellaneous Notes from Youyang ( 《酉陽雜俎‧天咫》 Youyang Zazhuo Tianch ). It mentioned that the laurel on the moon was five-hundred chi high, and that under the tree was a man who was chopping it. But the tree grew so fast that he could hardly leave a mark on it. Whenever he chopped, wounds of the tree healed simultaneously. According to the story, the man was Wu Gang, a man who came from Xihe. Since then, when an immortal in heaven made a mistake, he would be sent here to chop the tree as a punishment.