Abstract
Since the distribution of regional disparities in a country is closely related to the features of urban systems, the consolidation of urban systems is seen as an important means of reducing regional disparity. This paper discusses my investigation into the present situation and the changing processes of Japanese urban systems and also point outs the efficiency of the consolidation of urban systems as a measure for underpopulated areas.
After investigating the distribution of densely inhabited districts (DIDs), which are areas with more than 5,000 inhabitants and 4,000 persons per square kilometer in municipalities, an obvious areal differentiation was recognized in their distribution (Fig. 1): the distribution density of DIDs was coarse in underpopulated areas. From the viewpoint of the growth of DIDs seen during their population increase in 1980–2005, there is also a scale difference in DIDs compared with previously. As shown by the mean population increase rate (Table 2), the larger the DIDs the higher their growth rates, while many small DIDs disappeared after 1980. In addition, notable differences appeared between the 16 central prefectures of Japan and other regions when comparing the mean growth rates (Tables 4 and 5). If areas of the three metropolitan regions are clearly limited, more marked features of areal differences become obvious.
However, this phenomenon did not start with the current downturn. It has been underway since the high economic growth period (from about 1960–1973). I previously found a similar phenomenon on the basis of commuting area analysis (Morikawa 1990b). In this paper, a municipality that holds commuting areas with at least two municipalities with a commuting rate of more than 5% is defined as a central place. By analyzing the commuting areas of these central places and their rates of change from 1985 to 2000, although this period was economically unfavorable, it is found that the commuting rate in each municipality has generally increased so that the municipalities outside these commuting areas have decreased. The mutually dependent areas formed by two neighboring municipalities as well as an areal type in which municipality A is dependent on municipality B and municipality B is dependent on municipality C with larger centrality in that order, have increased in areas with unfavorable living conditions, while the existing commuting areas in the central places have not expanded as much. However, the existing commuting areas have experienced a structural change where not only partially dependent central places such as Yokohama and Kobe but also common commuting areas and unfinished common commuting areas have gradually developed. While common commuting areas are formed through the connection of two neighboring commuting areas (e.g., Maebashi and Takasaki), they are not formed without the full development of another commuting area and remain as an unfinished common commuting area.
There are currently three types of municipalities that occupy 54% of Japanese territory which are designated as underpopulated areas based on the continually decreasing population rate or poor financial situation: original municipalities in underpopulated areas; municipalities regarded as a whole; and municipalities with some underpopulated areas within a new municipal area formed by amalgamation in the Heisei period. As the population decrease in these underpopulated areas is closely related to a similar decline in the central places, the consolidation of urban systems is considered an important measure for underpopulated areas. An association for determining how to establish well-lived autonomous areas (teijujiritsuken koso kenkyukai) recently established as a private consultative body for the minister of general affairs in 2008 proposed the consolidation of central cities with a population of 50,000 to 100,000 inhabitants as a measure for consolidating underpopulated areas. ...
