Tokyo’s 20th Century Experience of Planned Poly-centrism: Population Density
This is a report about the change in population density of Tokyo between 1985-1995. Plan for Tokyo of Figure 4 has been superimposed to show the relationship between population change and the designated subcentres. The dominant feature is the massive decentralization of population from the metropolitan core to the surrounding region. The 23 ward area saw a net loss of 872 565 residents between 1970 and 1995, even though some of the 23 wards, such as Nerima and Itabashi in the north-west, and Adachi in the north-east, saw significant population gains.
Net losses of the population were also seen in the central wards of Yokohama, and would certainly also have been seen in the oldest parts of
Kawasaki near Tokyo bay, but for the fact that Kawasaki is shown here as one unit because the 1970 census does not give separate population figures for its different wards, and population growth in the western parts of Kawasaki more than balance the losses in the east. The suburban areas surrounding these core areas of Tokyo, Kawasaki and Yokohama have, on the other hand, seen enormous increases in population, with a total increase of over 10 million between 1970 and 1995.
The decrease in population in the central areas within and around the Yamanote loop line is striking. This area includes all of the ‘city subcentres’ except the coastal subcentre which is primarily in Koto which has seen moderate growth. Just outside this central area of significant population loss is a second ring, comprising virtually all the rest of the central 23 areas which have either seen moderate population loss or small population gains. Outside this second ring is a third, broad belt which has seen the most intensive growth in
population density, with increases of over 1500 persons/km2 over 25 years. Stretching clockwise from the southern part of Yokohama in Kanagawa prefecture, through Tama and Tachikawa in western Tokyo, Tokorozawa and Urawa in Saitama, to Kashiwa and Funabashi in Chiba, this belt is over 30 km in width at its widest in Kanagawa, and almost everywhere is over 20 km wide. The two arcs of highest population growth of over 2500 per km2 are seen to the south in the mid-part of Kanagawa prefecture, and in the north from Tokorozawa along the outer belt railway line to Funabashi.
Andre Sorensen, “Subcentres and Satellite Cities: Tokyo’s 20th Century Experience of Planned Polycentrism”, International Planning Studies, (The University of Tokyo,2001), 9-32.