Migration policy is one of the three pillars of population policy, though it is not always recognized as such. In modern Japan, the Meiji Restoration was synonymous with the opening of the country, leading to a drastic change in migration policy. Internal migration gradually increased, and the emigration policy brought many Japanese overseas. The expansion of Japanese territories boosted both immigration and emigration, a trend that ended abruptly with WWII. Post-war migration was characterised first by massive internal migration that supported the rapid economic growth of the 1960s, followed by international migration from the 1990s onward to address labor shortages and diversification of the society. Migration policies of the twenty-first century are struggling to face the population decline.