Creation and evolution of the open space in the sub center high raise zone of Nishi Shinjuku [Japan]

In the early 1960's a new concept in Japanese urban planning appeared, the fukutoshin (sub center). This concept aimed to change the single centered structure of the city that was located in the Marunouchi area. Due to this three sub-centers were proposed ; Ikebukuro, Shibuya and Shinjuku. The intention of this paper is to understand the conception and composition of the public open space in Nishi Shinjuku, and its final results. To achieve this understanding an analysis from a historical point of view of the creation and evolution of the fukutoshin in West Shinjuku is conducted as well as a study of the environmental particularities of the urban traffic network changing process, which is associated with the development of the area. The main idea of the structure for the plan of the fukutoshin was focused on creating an economical and administrative capital for Tokyo, Japan and Asia, based on the total restructure of the Nishi Shinjuku area. One of the key points of the plan was the separation between cars and pedestrians as well as the increase of the percentage of open space in the area, with the intention of expanding the access of such areas to the general population. For this reason it is important to understand the function and plan of the different open spaces of each block, which were created surrounding the construction of the buildings. This was possible under the process of transference of volume in a way to allow, in exchange for the extension in the height limits of the buildings, a higher percentage of open space areas in each block. Besides the advance planning of the general project, this study finds that the original proposal of the plan for the management of the fukutoshin was not totally fulfilled in its conception of the open spaces, since there exists a considerable variation between the percentage ratios of the open space areas at each one of the eleven central blocks as well as an absence of agreement in the design and the network connection of the areas. Through a detailed analysis of the area and the contraposition of the data, it is possible to achieve an understanding of the reasons that influenced in obtaining that result.