In the context of the general trends towards gender equality in major socioeconomic factors in Japan and other industrialised countries, this paper highlights and explains three distinctive features in the temporal pattern of the sex ratio of Japan's interprefectural migrants since the 1950s: a high level, an upward trend, and systematic fluctuations around the trend. The high level is explained by the 'base camp' nature and the 'motherly principle' of the Japanese family system, as well as the properties of the tightly-knit groups that have been the basic functioning units of Japanese society. The upward trend is explained by a weakening of the Confucian superstructure and a strengthening of the motherly principle in the Japanese family system. The systematic fluctuations are explained by the major changes in Japan's spatial economy. Drawing upon the insights of major Japanese social thinkers, Hayao Kawai and Chie Nakane, this research infers that, relative to the females in Canada and probably other Western industrialised countries, women in Japan are more prone to forsake long-distance migration as a means to achieve economic and career goals, so that they can enjoy closeness to their mothers and avoid the potentially negative consequences for their children of the whole family's long-distance relocation. © 2003 John Wiley and Sons, Ltd.

Family system Japan Migration Spatial economy

family structure Japan migration determinant sex ratio internal migration