Hyakki Yagyō

Hyakki Yakō (百鬼夜行; lit. "Night Parade of One Hundred Demons") was a Japanese folk belief. The belief holds that every year yōkai, the Japanese supernatural beings, will take to the streets during a summer night. The game Hyaku Monogatari was based on the folklore.

It was a popular theme in Japanese visual art. An early example is the famous 16-century handscroll Hyakki Yakō Zu (百鬼夜行図, with zu meaning "picture"), attributed to Tosa Mitsunobu, in the Shinju-an of Daitoku-ji, Kyoto. Notable works of this motif include those by Toriyama Sekien and Utagawa Yoshiiku. These works are more often humourous than frightening.