As a boy, Takeda Shingen was brought by his mother, Lady Oi, to this temple, Kochoji, where he studied scholarship and the art of war under its chief priest, Kishu Gempaku. When Lady Oi died in 1552 at age 55, she was buried here, and the temple's mountain name, Zuiunzan, derives from her posthumous Buddhist name. Kishu Gempaku later officiated when Shingen took Buddhist vows.