Qingyuan Xingsi (; Korean: ) was a Zen Buddhist monk during the Tang Dynasty. Three of the five traditionally recognized houses of Zen are commonly believed to have developed out of his lineage: the Caodong/Sōtō, Yunmen/Unmon, and Fayan/Hōgen. There is scant information about his life. He is said to have lived in the Quiet Abode Temple on Mount Qingyuan. The Transmission of the Lamp claims he was Huineng's foremost student, although this was written during the Song Dynasty over 200 years after Qingyuan's death.: In fact, in the oldest version of the Platform Sutra found among the Dunhuang manuscripts, which dates to about 850 CE, Qingyuan is not listed as a student of Huineng at all. The earliest source of information about Qingyuan comes from the Anthology of the Patriarchal Hall, which was completed in 952 by the monk Wendeng.: The scholar Albert Welter suggests that Wendeng may have invented Qingyuan in order to legitimize Shitou Xiqian, Qingyuan's supposed student, and in turn himself since he was descended from Shitou.: Shitou's original teacher, Huineng, died when Shitou was only 13, so Qingyuan was necessary for him to receive legitimate dharma transmission.: