In March, Hidenori Sakanaka, a former director of the Tokyo Regional Immigration Bureau, was contacted by — and met with — a group of people he had never dreamed of crossing paths with: asset managers from global investment firms.

Sakanaka, who now heads the Japan Immigration Policy Institute in Tokyo, was asked to explain Japan's notoriously tight immigration policies and his proposal to drastically ease them to save Japan from the severe consequences of its rapidly aging and shrinking population.

Sakanaka said the asset managers showed strong interest in a remark made the previous month by Prime Minister Shinzo Abe, and that they were wondering if they should buy Japanese assets, such as stocks and real estate.