" Long hair binding the heart of the king " was not a specific poem but a commonly used phrase in novels that appeared in many online novels. According to my knowledge of online literature, this phrase first appeared in an ancient novel called Song of Everlasting Sorrow. The phrase " the heart of the monarch grows long hair " was a line in a poem written by Bai Juyi to Emperor Xuanzong of the Tang Dynasty. However, this term was also widely used in online novels. The specific origin of this term may vary according to the novel and author.