Prof.Kondo Astushi "Even if other countries take in 20% of population as immigrants, the ratio of foreigners usually remain at 10% because they let immigrants to become the citizens. If Japan follows this system encouraging immigrants to get naturalized, the proportion of foreigners won't rise."
http://x.com/i/status/2057416684223492478
Prof. Kendo Astushi is a member of the Immigration Policy Consultative Committee at the Immigration Service Agency of Japan.