During the Tokugawa shogunate, people in Edo brought fishes out of Tokyo Bay and ate them. Sushi was originally called Edomae which literally means “from Tokyo Bay”. Therefore, the bay has been important for people in Tokyo for a long time.

Tokyo Bay is originally shallow for some distance from the shore. Therefore, a lot of land has been reclaimed since 1890. First few of them were reclaimed for protection. The government built fortresses on those lands. Eventually, about 250 square kilometers were reclaimed, and a lot of important buildings were built there. Tokyo International Airport (Haneda) and Tokyo Disneyland were a few of them. Many of them are tall mansions and offices as well as shopping malls.

In central Tokyo, you can easily notice that every single river is muddy and dirty. Rivers eventually flow into Tokyo Bay. The dirt has caused environmental issues since Japan accomplished economic success in the 1960s. In order to encourage the development, people and the government ignored the issues. When environmental issues started to be discussed both inside and outside of Japan, the government finally recognized the situation, and encouraged people to clean Tokyo Bay. At that time, it was dangerous to eat fishes from Tokyo Bay because so much chemical was in the water. Legal restriction was imposed, and the water is much cleaner now. However, dirt on the bottom of the bay still contains the accumulated chemical. Since fishes eat plankton out of the dirt, it is still dangerous to eat them.