Water is an eternal problem for humankind. Culturally too, the Japanese have a deep relationship with water. Good-quality water is essential for making Japanese food, such as rice, tofu, and Japanese confectionery, as well as sake. And water displays its power in purification and ablutions at shrines too.
It was about four centuries ago when Tokugawa Ieyasu (1543–1616) stepped onto land that was swampy as far as the eye could see and began building Edo (present-day Tokyo) as the center of Japan’s new politics. There was one big problem, however: The land was not blessed with fresh water. Crucial for Edo’s development, the securing of water supplies turned into an enormous project.