Tradition: Japanese Mythology
Alternative Names: 赤鼠, Red Rat, Ōshū Red Rat, Island-Crossing Rat
Category: Rat
The Myth
Aka Nezumi, meaning “Red Rat,” is associated with a legendary plague of rats recorded in the Japanese miscellany Ichwa Ichigen, written by Ōta Nanpo. According to the account, in around April 1679, fishermen off the coast of Tsugaru in Ōshū saw what appeared to be an enormous shoal of sardines approaching the shore. When they cast their nets, however, they discovered that they had caught countless rats instead. The creatures had white undersides, with red heads and red stripes along their backs.
The fishermen dragged the rats ashore and killed as many as they could, but the survivors fled inland, reportedly spreading as far as the territories of Nanbu and Satake. The rats devastated the countryside, destroying rice seedlings, eating bamboo roots and other vegetation, invading houses, and consuming stores of grain overnight. Some were later found dead in enormous heaps in the mountains, with hundreds of bodies piled together.
The same account mentions similar incidents elsewhere in Japan, including rats caught in fishing nets at Shinkai in Shimōsa, where sailors called them “island-crossing rats.” It also records a rat infestation in Mino Province in 1791 that damaged crops. These stories preserve the memory of destructive rodent invasions that were interpreted as extraordinary events.
Sources
“Akanezumi.” 新版TYZ 妖怪図鑑 (New TYZ Yokai Encyclopedia). https://tyz-yokai.blog.jp/archives/1077180876.html