The purpose of this study is to describe the residential segregation patterns by 5-year age group and their recent changes in the Tokyo metropolitan area, and to explain the effects of migration on the segregation pattern. This study adopted the viewpoint of cohorts, and yielded the following results:
First, most of the segregation patterns of 14 age grouups show a concentric tendency; the age groups 0-14 and 30-44 tend to be distributed more densely in the outer part of the metropolitan area (Outer Tokyo), and the age groups 15-29 and 45 and over tend to be distributed more densely in the inner part of the metropolitan area (Inner Tokyo). However, in the period between 1980 and 1985 the age groups 15- 19 and 45-49 shifted their distributions from Inner Tokyo to Outer Tokyo, and the age group 30-34 shifted from Outer Tokyo to Inner Tokyo.
Second, two main migration flows are observed: the migration of the young from outside of the metropolitan area to Inner Tokyo, and the migration of young families from Inner Tokyo to Outer Tokyo. These two migration flows have effects on creating the principal age segregation patterns. Third, with applied cohort analysis, an increase of the young who were born and brought up in the Tokyo metropolitan area, “the Native Young”, was observed, as well as a decrease of the young who immigrate into the metropolitan area from the outside, “the Foreign Young”.
Fourth, the recent change of the segregation pattern of the 15- 19 age group after 1980 is caused not only by the recent decrease of “the Foreign Young”, but also by the increase of “the Native Young” who moved to Outer Tokyo with their parents in the past.
Fifth, the age segregation in the Tokyo metropolitan area will be probably weakened by the maturity of the suburbs in the next decades.