The Hokkaido Prefectural Government drew up development plans around 1956 for one of three islands and a group of islets off its coast when the then Soviet Union agreed to return them to Japan, according to plans filed at a Sapporo document center.
The development plans are for Shikotan Island and the Habomai islets, which were seized by Soviet troops at the end of World War II along with two larger islands, Etorofu and Kunashiri. The four still belong to Russia despite Tokyo's demands they be returned.
The plans, obtained Monday by Kyodo News, were kept at the Archives of Hokkaido.
The plans show that the Hokkaido government requested that the state introduce special legislation and make a fiscal commitment to promote development of the islands. They also detail schemes for improving infrastructure and buildings on the islands.