Kanshu (945-August 17, 1008) was a priest of the Tendai sect in the mid Heian period. His secular surname was of the Shiki clan.
Kanshu entered the temple on Mt. Hiei and became a Chigo (child in Buddhist possession) at the age of 11, afterwards becoming a priest and receiving the kanjo (initiation of a succession where water is poured onto the successor's head) from Yokei in 985. Kanshu studied under Seiyu as well. In 997, together with his teacher Jitsuin, he criticized a book on the Tendai sect which was sent from Baisong, China. Later that year, he became the Chori (chief priest) of Onjo-ji Temple, and in September 1000 he was appionted as a Daisojo (a Buddhist priest of the highest order). When FUJIWARA no Michinaga erected the Jomyo-ji Temple in Uji in 1005, Kanshu became the Kaisan (the founder of a temple as the first chief priest). After his death, he was given the posthumous name (Shigo) "Chisei" in January 1020.