Doin (1741 - July 1, 1813) was a priest of Jodo Shinshu (the True Pure Land Sect of Buddhism) during the middle to late Edo period. His homyo (a name given to a person who enters the Buddhist priesthood) was Tainin. His azana (adult males nickname) was Doin. His go (a pen name) was Sasshu. His shi (a posthumous name, can also be pronounced okurina) was Joshinin. He was born in Satsuma Province.
At first he lived in Sainen-ji Temple in Kawachi Province, but later he moved to Chokyu-ji Temple in Buzen Province. At first he studied Shingon Sect, but he was converted to Jodo Shinshu and studied under Soboku and Soyo.
He criticized Sangoanjin of noge (master) Chido in Hongan-ji Temple Gakurin (school.)
In 1803 at a magistrate's office in Nijo, Kyoto and in the following year 1804 at a magistrate's office of a temple in Edo, he and Daiei argued with Chido and refuted his argument.