Japan was never part of the British Empire, but its traffic also drives on the left. Although the origin of this habit goes back to the Edo period (1603–1868), it was not until 1872 that this unwritten rule became more or less official. That was the year when Japan’s first railway was introduced, built with technical aid from the British. Gradually, a massive network of railways and tram tracks was built, with all trains and trams being driven on the left-hand side. However, it took another half century until 1924, in which left-hand traffic was clearly written in law.