Shimoda is a city and port located in Shizuoka Prefecture, Japan. As of 1 August 2019, the city had an estimated population of 21,402 in 10,787 households, and a population density of 200 persons per km². The total area of the city is 104.71 square kilometres. 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.