Constant churning and persistent regularity in population and industrial locations: Evidence from Japan

Population agglomeration is a manifest and global trend. If it is identified by the set of contiguous areas with population density of at least 1,000 people per km2 and total population of at least 10,000, such areas accounted for 44.6% (1.6%), 43.6% (2.4%), 48.7% (2.9%), 47.0% (3.8%) and 77.1% (12.4%) of the total population (area) in Europe, the US, China and India, and Japan, respectively, in 2015. While the case of Japan is exceptional due to its relative scarcity of land, the disproportionate concentration of population appears to be a ubiquitous phenomenon across the world. Thus, it is natural to view economic geography in terms of the system of (economic) cities.

Substantial evidence (e.g. Bettencourt et al. 2007) has indicated strong correlations between socioeconomic quantities and population sizes of cities (e.g. wages, GDP, number of patents produced for positive correlations, amount of crime, and the level of traffic congestion for negative correlations). As such, it is of particular interest to know and explain where and what sizes of cities form, and which cities grow or decline.

It is well known that a city size distribution in a relatively autonomous economic region—typically a country or a fairly integrated set of contiguous countries such as the EU—approximately follows a (region-specific) power law (e.g. Decker et al. 2007). Figure 1 shows the rank-(population) size distributions of cities in Japan in 1980, 2000, and 2010 (where the rank indicates the ranking in terms of population size). Throughout the 30-year period, the upper tail of the city size distribution maintains a fairly persistent power law.

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