Regional urban systems in Japan have a close relationship with prefectural territories. The population of prefectural capitals has gradually been controlled by the population scale of the prefecture. Analyzing the migration flows among 649 cities
in 1980, a city usually has a close connection to other cities within its own prefecture and forms a regional urban system with the hierarchical structure in which a prefectural capital is set up at the top. The hierarchical structure of the regional urban
system in each prefecture mostly reflects features of its starting point, although regional differences between core and periphery areas have appeared in the process of urban growth.