Eison (叡尊) (1201–1290) was a Japanese Buddhist monk who founded the Shingon Risshu sect. Eison entered religious training when he was eleven years old, studying initially at Daigo-ji and later at Kongōbu-ji. At the age of 34, while at Saidai-ji, he made the decision to become a fully ordained monk. However, since the process of ordination in Shingon Buddhism had been lost by this point in time, Eison decided to self-ordain, and along with three companions performed his own ordination ceremony at Tōdai-ji in 1236.