Tradition: Japanese Mythology
Alternative Names: 鼠大明神, Great Rat Deity
Category: Rat
The Myth
Nezumi Daimyōjin is a legendary giant rat associated with Sakaki in Hanishina District, Nagano Prefecture. Its story is connected to local place names, including Nezumi and Iwahana. According to tradition, a dangerous infestation of tsutsugamushi, or mites associated with scrub typhus, once plagued the village of Nezumi-juku. Seeking a solution, the villagers asked a gigantic rat living in a nearby cave to eliminate the pests. The rat agreed and devoured them all within three days.
Grateful for its service, the villagers offered the rat rice and fish every day. Growing ever larger, however, it eventually began roaming the village openly and devouring rabbits and chickens. Matters reached a crisis when it bit off an elderly woman’s wrist. Although the villagers remembered its earlier help, they decided the creature had become too dangerous to tolerate. Unable to find a cat capable of confronting it, they sent a representative across the sea to Tang China to seek a gigantic, tiger-like cat.
The great Tang cat agreed to help and travelled to the village, where it fought the rat in a battle whose roars echoed across the surrounding region. The cat eventually prevailed, and the rat struck its head against a projecting rock called Iwahana before dying. A nearby lake then burst its banks, and the rat was swept away by the raging flood. The victorious cat was also carried off by the waters; although it managed to crawl ashore, it soon died from exhaustion. In gratitude, the villagers established Karane-ko Shrine in honour of the cat and built a small shrine to the fallen rat, commemorating it as Nezumi Daimyōjin.
Sources
“Nezumi Daimyojin.” 新版TYZ 妖怪図鑑 (New TYZ Yokai Encyclopedia). https://tyz-yokai.blog.jp/archives/1077214312.html