From the 1960th to 1980th years in the second half of the 20th century, numerous “sea city concepts” were proposed as a new city image. Among these concepts, in Japan, the sea city concept reflecting the current urban development situation of that time, was drawn by the architects as an image of the ideal city.
During that period, in Japan for the purpose of the further economic development, the landfilled industrial zones were created in the surroundings of large metropolitan areas of Tokyo, Osaka and Nagoya. It led to the concentration of the population due to the people fleeing to the big cities from the provinces for employment, which created various problems of big cities such as population overcrowding, land shortage, traffic jams, air pollution, etc., so the different tasks became apparent.
As a way to solve such problems, a sea city plan has been proposed. The oldest initiative was the Tokyo Bay concept of 1958 which proposed the creation of a new city by creating a new land by landfilling Tokyo Bay. However, that initiative only covered the expansion of the existing land, and didn’t make any advantage of “ocean” resources.
For that reason, the further proposals subsequently enabled taking advantage of the sea by creating the canals, artificial islands or pile-style structures which led to adoption of proposal to float up. After that, the sea city concepts basing on the floating type had increased, and the subjected water area transited from the shallow water to the offshore area.
Furthermore, the authors are planning to arrange the process of transition of the concept of the sea city by taking into account the changes the way oceans are treated and the structures relative to time.