The epitome of the future Japan from the perspective of demographic composition: —Application of compositional data analysis to population studies—

Demographic composition, e.g., population composition by age-groups, is one of the most basic information for discussing regional issue or planning. The present study compares the future Japan through 2010–2060, estimated by National Institute of Population and Social Security Research, with all municipalities in 2010 from the perspective of demographic compositions classified by fiveyear age groups (0–4, 5–9, ..., 90+). The (dis-)similarity of compositional data can be measured with Aitchison distance, one of the core concepts of compositional data analysis. We create choropleth maps based on Aitchison distance. The maps, for example, indicate that the demographic composition of Sobetsu-cho of Hokkaido prefecture of 2010 is the most analogous of the future of Japan of 2060.