## V Return (U-turn) migration

“U-turn migration” has been widely used as an expression meaning return migration in Japan. In this section, we observe the state of U-turn migration by creating relatively simple migration patterns based on prefecture-level data of birthplace for the present residence and migration process (migration experience) between these two places. To be more concrete, migration patterns are defined as follows. For those whose birthplace and present residence are both in prefecture A, there are two possibilities. One is a pattern of “within-prefecture settlement” where there is no record of living outside prefecture A in a respondent's migration history (as far as present data can grasp), and the other is “U-turn to birth prefecture” where a respondent has experience of living outside prefecture A. When one's birthplace and present residence belong to different prefectures, this person was treated as an “I-turn” migrant. It should thus be noted that U-turn migration observed here is not limited to moves undertaken by those who migrated from non-metropolitan to metropolitan areas and “U-turned” to the birthplace.

Table 16 shows age-specific U-turn migration of household heads and their spouses. Firstly, out-of-prefecture migration rates, which indicate the percentage of those who have experienced at least one out-move from birth prefecture, show that in every generation, the rate is a little higher for males than for females. This result fits the general understanding that the distance of migration tends to be long for males and short for females. In the case of males, the out-of-prefecture migration rate is highest for those under 30 years old. The percentage of those who have experienced out-moves generally decreases with age. As for females, differences by age are not clear until 50 years old. After that, however, the out-of-prefecture migration rate becomes lower in the higher age group. “I-turn rate,” i.e., the percentage of those living in prefectures other than birth prefectures (Table 16(3)) is generally lower in higher age groups, except for 50-54 male and 45-49 female.

Percentages of I-turn migrants among all out-of-prefecture migrants (Table 16(4)) show a decreasing trend from younger to older generations, but after they hit bottom in the 40-49 age group, these percentages start increasing up to the 55-59 age group. “I-turn rates (b)” are high among generations around the 55-59 age group. This means that the percentages of those who have not re-migrated to birth prefectures are high. Trends among female respondents are somewhat different. I-turn rates (b) decrease from the age groups of 20s to 40-44, and then increase up to 60-64.

The percentage of U-turn migrants of the total out-of-prefecture migrants (Table 16(5)) is 27.2% for males and 24.9% for females. In the case of males, the percentage decreases from the age groups of 40s to 55-59. The generation with the lowest U-turn rate seems to include a large number of people who moved from non-metropolitan to metropolitan areas in the period of high economic development and settled in cities. The increase of U-turn rates in ages over 60 could be partly caused by return migration to birthplaces etc. after retirement. Females show almost the same tendency, although some generational differences exist.