The "Night Parade of One Hundred Demons" refers to yokai monsters forming a procession and marching toward somewhere at night. Depicted as the main characters, yokai primarily take the form of instruments and tools, such as a biwa lute pulling a koto harp, gongs, and pots, but also includes demons and animal-like yokai. According to the tsukumogami ancient Japanese belief, instruments and tools are thought to acquire life after the passage of time, and many yokai hence take on their form. For yokai illustrations, it was traditional to use the picture scroll format, a type of ancient Japanese paintings. Japan's oldest surviving Night Parade of One Hundred Demons Picture Scroll is said to be that by Tosa Mitsunobu, an artist of the Muromachi period (1336–1573). Various variations of Night Parade of One Hundred Demons Picture Scroll were also created during the Edo period (1603–1867). While these picture scrolls greatly influenced other yokai illustrations, many of their artists remain unidentified.