The Kōyasan University 高野山大学 library holds an old manuscript of the Bianzheng lun 弁正論. I examine whether this old manuscript is a copy of that mentioned in the list of texts imported by Kūkai 空海, and conclude that there is a possibility that it is. In addition, I find two points at which this old manuscript agrees with the Bianzheng lun quoted in Shinran’s 親鸞 Kyōgyōshinshō 教行信証.
