I’ve been living in Tokyo and Yokohama since 1983, and I have seen rats a handful of times in Tokyo: once in a subway station, walking along the tracks; a couple of times in Shibuya in the early morning, picking through garbage; once or twice in residential neighborhoods. One sighting every five years is not a lot, I admit.

Twenty years ago, I knew someone who worked for one of the large, upscale department stores, and she said they spent a lot of money and effort to try to control the rats in their elegant but old and porous building—which, like most department stores here, had many food shops in the basement.