This study analyzes Japan’s post‑war population redistribution challenges, focusing on the dual problems of extreme overconcentration in major metropolitan areas such as Tokyo, Osaka, and Nagoya and underpopulation in rural prefectures, driven by rapid economic growth, interregional migration, and shifting labour patterns. It reviews the evolution of Japan’s national and regional development plans from the 1950s to the 1970s, showing how industrial expansion, infrastructure investments and the “growth pole” strategy accelerated rural depopulation while concentrating young labour and university students in cities. By the early 1970s, migration levels began to decline, signaling a turning point shaped by demographic transition, fertility decline, and capacity limits in metropolitan areas. The report argues that Japan’s third comprehensive national development plan (1977) must address aging rural populations, unequal regional development, and redistribution through settlement policies that improve living conditions, decentralize education and employment opportunities, and rebalance growth between urban and rural regions