Chujin (1065 - November 25, 1138) was a Buddhist monk of Tendai Sect in the late Heian period. His father was MINAMOTO no Tadasue, Tosa no kami (the Governor of Tosa Province), who was a son of MINAMOTO no Yorihira. He was also called Otani Zasu (temple's head priest). He hailed from Sado no kuni (Sado Province).
He learned the Tendai doctrine from Chogo, Kakujin and Ryoyu of Mt. Hiei.
Initially he resided at Manju-in Temple in Rakuhoku and later moved to Kitadani Toyo-in Temple of Mt. Hiei
He founded satobo (a small village temple) called Juraku-in Temple at Higashiyama Otani in 1115 and was appointed to Gon-Risshi (a high-ranking post of priest) in 1118, Tendai Zasu (head priest of Mt. Hiei) in 1130 and Daisojo (head priest of the sect) in 1137. He strived for the development of the Eshin school of Tendai Doctrine and Chujin's school was called Toyoin school.