The shimotsuki festival has been passed down over the centuries in the community of Shimoguri, located in Kamimura in Nagano Prefecture’s Shimoina District. The population once staged a revolt against the oppression of the Toyama clan who governed the region. Disease spread in the aftermath and was thought to be the work of the slain clan. The festival was initiated to clear their resentment. The masks of dead spirits dance amid clouds of steam from boiling water.