TessoEdo Picture-Book Standard, Traditional Iconography

Based on Toriyama Sekien’s “Tesso” motif, it appears as a giant rat draped in robe-like shadows, with red eyes and teeth said to be iron-hard. Its origin lies in the vengeful spirit tale of Raigō tied to disputes over the ordination platform at Onjōji, where rivalry between Enryakuji’s Sannō faction and the Miidera side was cast into story and overlapped with real rat damage to temple sutras and treasures. Names vary by period and source, with “Raigō Nezumi” and “Miidera Nezumi” coexisting. Medieval war tales exaggerate its numbers into a calamity of swarming rats, while from early modern times it links to shrine legends of pacification and blessings. Chronologies in records do not always align and the tale is highly narrative, yet shrine and temple names, linked verse, and oral lore support a core tradition. In some regions, extermination stories feature a great cat of Mount Hiei or guardian deities, reflecting the boundary-conscious rivalry between two religious centers.