Legend has it that the daughter of a god descended to earth and made a private lifelong promise to a young and promising general who protects the country. The two only envy mandarin ducks but not immortals, but they are separated by yin and yang in the war against enemy aggression. From then on, the goddess washed her face with tears, and finally dipped her pen in blood and tears. Before his death, he used the sorrow of lovesickness to compose a touching pipa song - "The Ballad of the Moon".
Since then, it has been spread in the world that as long as a woman possesses the music score of "The Ballad of the Moon", she will be protected by the goddess and will also be a saint who maintains peace in the world.