Shimoda (下田市 Shimoda-shi) is a city and port located in Shizuoka Prefecture, Japan. As of September 2015, the city had an estimated population of 22,931 and a population density of 219 persons per km². The total area was 104.71 square kilometres (40.43 sq mi). In the 1850s, Japan was in political crisis over its increasing inability to maintain its national seclusion policy and the issue of what relations, if any, it should have with foreign powers. For a few years, Shimoda was central to this debate.