Tsurube-bi is a mysterious fire that moves up and down from treetops at night like a hanging bucket. It appears in Toriyama Sekien’s Gazu Hyakki Yagyō, interpreted as the fiery apparition from Kyoto’s Saiin noted in Edo-period ghost tales. In Shikoku and Kyushu, it’s said to be a wood spirit turning into a bluish-white fireball that dangles from branches. The flames do not burn things, and faces of people or animals sometimes appear within. Considered a type of will-o’-the-wisp, it’s often reported on quiet mountain paths.