Overview: In 1872, when Japan’s first railway opened between Yokohama and Tokyo, the population of Tokyo was less than one million. Fast-forward 150-odd years, and it has increased to well over 13 million. If you add the larger metro area, that number swells to 35 million. The continued growth of Tokyo’s population has necessitated constant additions and revisions to its infrastructure—and the city’s importance as Japan’s political, financial and cultural capital means those additions and revisions must be carried out without interrupting its daily flow. That balancing act lies at the heart of this edition of Japanology Plus.