- Death: 1582
- Distinction: Buddhist priest
Kaisen was originally from Mino province and may have been related to the Toki family. He fled Mino to Owari province following the rise to power of Saitô Yoshitatsu and at length made his way to Kai province. There he made the acquaintance of Takeda Shingen, who being much impressed with him made Kaisen the head abbot of the Irin-ji in Kofu. In 1582, during the Oda and Tokugawa invasion of the Takeda domain, the Irin-ji was accused by the invaders of sheltering Rokkaku Yoshiharu (a former enemy of the Oda) and was burned along with all its monks. Kaisen is remembered for his calm demeanor in the face of their impending destruction, advising his monks, we are told, to set their minds at ease so that even the fire might be thought of as cool and refreshing.
- Initial text from Sengoku Biographical Dictionary (Samurai-Archives.com) FWSeal & CEWest, 2005