Popular culture has ensured that at least one or two key elements in the story of Japan's unique and often turbulent relationship with the Western world have become familiar to a wider audience. Stephen Sondheim's 1975 musical Pacific Overtures, for instance, charts the course of events subsequent to that momentous day in the nineteenth century when Japan was finally rudely awakened from its quarter-millennium of feudal stability by a dramatic intervention of modernity. The day in question was 8 July 1853, when Commodore Matthew Calbraith Perry of the United States Navy sailed into Uraga harbour with his powerfully armed ironclad steamboats, the kurofune (‘black ships’); and to understand the boldness and historical significance of Perry's adventure, one has to travel back in time a quarter of a millennium further still, to 1603. For it was in that year that Ieyasu Tokugawa finally acceded to an office familiar to Westerners, once again, from populist sources, in this case James Clavell's 1975 novel and its subsequent film and television versions: the title of military dictator of all Japan, or Shōgun.

Having attained this sovereign position at great cost by finally subjugating the powerful regional warlords (daimyō), the Tokugawa family was understandably anxious to preserve the fragile centralised power it had established. In particular, wary of the colonial ambitions of the foreign nationals then resident in Japan – and of any alliance between these and their daimyō subordinates – they embarked on a campaign of draconian measures to protect their country from the perceived alien menace.