Li Bai seldom mentions his family in his poems, and there are few records about his family in historical materials, except that his father's name is Li Ke, and Li Bai's sister Li is only common in some unofficial history rumors.
According to legend, Li Bai's sister Li is a beautiful and talented girl. Li is two years younger than Li Bai and studied with his brother when he was a child. On one occasion, Li Bai's mother wrote a pair of four-character couplets to pair their brother and sister. Couplets are simple: beautiful scenery. After listening to this, Li Bai made a couplet without thinking: Spend a full moon. This couplet is obscure because it contains the name of Li Bai's sister.
Not to be outdone, Li immediately confronted Li Bai; Bottom line, this bottom line not only perfectly matches the top line, but also contains my brother's name, which is enough to show that Li is also a knowledgeable and intelligent person.
Li Bai felt sorry for Li, probably because of two things. When Li was young, although she had been betrothed to someone else, she did not marry early in order to be filial to her brother Li Bai. Later, Li Bai went out to travel. When he left his hometown, he took his fiance Li with him.
Li Bai may want to take his brother-in-law to the outside world to see the world. After a period of time, it is natural to let him go home and marry his sister. Unfortunately, however, her fiance Li died of a serious illness during the trip. Li Wei became a widow when she got married, and Li's fiance died while traveling with Li Bai, which is probably one of the reasons why everyone thinks that Li Bai is sorry for his sister Li.