Japan's elderly population (25%) is much higher than any other OCDE country (14.5% for the US). Investment in robot assistants for the elderly hasn't been particularly fruitful, therefore Japan is slowly turning to immigration to take care of them.
https://data.oecd.org/pop/elderly-population.htm#indicator-c...
http://foreignpolicy.com/2017/03/01/japan-prefers-robot-bear...
https://www.migrationpolicy.org/article/its-population-ages-...