After Japan opened up to the rest of the world in the 1850s after years of isolation, hundreds of British traders and sailors came to live in the country and became the largest Western expatriate community.
But while Britain was happy to trade with Japan, it felt uneasy about the country's legal system, which was considered rudimentary, patchy and unable to guarantee Britons a fair trial.
As a result, London insisted upon setting up its own extra-territorial courts to exclusively hear criminal and civil cases involving Britons. Western nations set up similar courts in other parts of Asia as well.