Search

This study aimed to understand the age‐specific internal migration patterns in Japan where more than a quarter of the population is aged ≥65 years and the national population is on the decline, focusing on the urban hierarchy. Demographic efficiency, which is the ratio of net to gross migration, was calculated for each migration flow between the levels of urban hierarchy in Japan based on the 2020 census. The results showed that the overall upward migration, which is a movement from lower to higher levels in the urban hierarchy, was dominant. A variation in migration patterns by age confirmed that young adults, especially those aged 20–24 years, moved up the urban hierarchy unidirectionally, while people of preretirement and retirement age moved down. The older adults (aged 75 and over) were inclined to move up. Regarding sex‐based differences, the demographic efficiency of women was higher than that of men. Additionally, the upward movement of women was predominant in almost all age groups. These findings suggest the possibility that aggregated migration behaviours may vary by sex, which has received little attention in previous migration studies focusing on urban hierarchies in other countries. Furthermore, this study discussed policy implications based on the observed patterns, such as the impacts of older adults' migration on social security at each hierarchy level and a possible relationship between women's upward migration patterns and future fertility decline. [ABSTRACT FROM AUTHOR]

In the past 10 years or so, there have been growing concerns in Japan that migration trends, such as large in‐migration to the Tokyo metropolitan area (TMA) at the national scale and large movements from the suburbs to the centres at the metropolitan scale, have widened the core–periphery disparities at each scale under national population decline. However, the COVID‐19 pandemic led to unexpected changes in these migration patterns, such as a weakened population concentration in the TMA. This study aims to examine internal migration trends from 2012, on axes of core–periphery in Japan and centre–suburbs in metropolitan areas, and the changes in the migration patterns caused by the pandemic in 2020. First, we prepared intermunicipal origin–destination tables by estimating the suppressed flows in 2012–2020 using the iterative proportional fitting technique, and then we calculated the net migration and migration efficiency indices based on seven area types: centre and suburbs of the TMA, centres and suburbs of major metropolitan areas, centres and suburbs of other metropolitan areas and nonmetropolitan areas. The results indicate that the 2020 migration efficiency in the centre of the TMA drastically dropped to the lowest level during the study period, contrasting with an upward trend in 2012–2019. The pandemic strongly affected the migration patterns from/to and within the TMA, with much net gain in the suburbs from the centre, but the impact of migration efficiencies among the other areas was minimal. These findings can help in providing direction for the postpandemic policy challenge of spatial planning in Japan, for example, the weakened but still widening disparities between the TMA and the other regions and the renewed threat of urban sprawl caused by the increased migration from the centre to the suburbs within the TMA. [ABSTRACT FROM AUTHOR]