"Nie Yinniang" was written down around 880 by Bei Xing. Yinniang is the daughter of Nie Feng, a general in the Cheng Yuan period (785-804). She is a famous character of the flying swordswoman type: she has peerless sword skills but can also perform feats such as leaping over mountains. Her training in these arts begins when she was ten years old, Bei reports. A nun sees Yinniang and asks the general if she could take the girl for training. Although he refuses, Yinniang disappears that night. "After a year," she says, "I was able to kill monkeys and tigers] and leopards . . . after three years I could throw my sword and strike down eagles and hawks without fail." The sword gradually shrunk to a few inches, and "flashed through the air so fast that the birds never knew" what killed them. In the fourth year, the nun takes her to a marketplace and shows her an evil man. She gives Yinniang a dagger and tells her to cut off his head, and she does, without anyone seeing her. Over the next year she trains Yinniang in the task of killing evil men and disposing of the bodies by turning them into pure water.
At the end of five years, Yinniang returns to her family. When she tells them what happened, they are afraid of her and she lives her life with them as she desires, even choosing her own husband. She and he (as her assistant) are hired by the local warlord, but when he sends her to assassinate a better man, she changes her loyalties.
In the eighth year of Yuanhe (813), Bei writes, she decided to go up into the mountains and look for sages who had achieved immortality. She was seen again in the Kai Cheng period (836-840), when she gave a warning to the son of her final employer. She looked as young as ever, but Yinniang was not seen again after that.