Tetsumonkai Shonin (1768–1829) was an ascetic monk of the Shugendo tradition in the Dewa Sanzan region of Japan, best known for undertaking the extreme practice of self-mummification (sokushinbutsu) after a life of rigorous fasting and austerities. His mummified remains are enshrined at Churen-ji temple, and he is remembered by devotees as a figure associated with healing and relief from suffering, though such benefits reflect popular devotion rather than documented historical fact. He is venerated as an example of extreme religious discipline undertaken for the welfare of others.