By Shingo Hori
International Development and Regional Planning Unit, Dept. of Urban Engineering
University of Tokyo

Tokyo, population 12.9 million (2008) is so densely-populated that there has been strong demand for more density than the underlying floor area ratio (FAR) allowed by the Building Code. Tokyo allows potential floor area to be transferred from sending sites to receiving sites allowing more intensive land use.

Meiji Life Insurance Building was preserved by transferring its floor area to the adjacent development.

Historic Tokyo Station transferred floor area to five developments, including two office buildings in the background.

Generally, the Building Code allows only one building on one site. In a Group Building Comprehensive Design, if conditions are met, a group of contiguous properties can be considered as one building site. FAR can be freely allocated to each building on the merged lot if total floor area as a whole is not more than total floor area allowed to the original lots. As a result, floor area can be transferred between property owners. Originally, this transfer mechanism was only available to developments consisting entirely of new buildings. However, an amendment of the Building Code in 1999 made it possible to include existing buildings in these merged lot developments.

Specified Block, first applied in 1964, is the system for designating maximum FAR and height and setback line in a block where developments for improving the urban environment take place. FAR bonus is applied if the project creates open space, develops infrastructure, preserves historic architecture or green space etc. The Tokyo government created a new system in 1999, Specified Block for important cultural properties, which can transfer floor area of preserved or restored important cultural properties, designated by the Ministry of Education, Culture, Sports Science and Technology, to developments in the same block. Two important cultural properties, Mitsui main building and Meiji Life Insurance Building, transferred their floor area to the adjacent developments. Furthermore, if planned as one project, more than two adjacent blocks can be designated as a specified block. This made it possible to transfer FAR beyond a street.

The Redevelopment District Plan is another measure to realize TDR. It is intended to convert the land use of a large scale area. Developing infrastructure or public facilities can lead to FAR bonus. By distributing designated floor area to each block, FAR can be transferred between property owners.

In 2000, Special Case Floor Area Ratio Application District was created to realize TDR. The Tokyo government can designate an area which has a high standard of utilities as a special case floor area ratio application district. As of 2008, the only case of such a district is Otemachi, Marunouchi, Yurakucho District (116.7ha), designated in 2002. In that district, the sending area can be historic architecture, cultural facilities or areas with building height limits. Receiving areas must front broad streets and have a suitable development plan for intensive land use. Unutilized floor area of a sending area can be transferred to receiving areas at one-to-one ratio. Tokyo station, an important cultural property, has transferred its unused floor area, about 15ha, to five developments near the station. About 50 billion yen was paid for these transactions, and Tokyo station is going to be restored to the original condition. The station still has about 3ha unutilized floor area.