Japan also does not allow its adult citizens to have other nationalities. Those who have Japanese and another nationality from birth are required to choose one

Japan also does not allow its adult citizens to have other nationalities. Those who have Japanese and another nationality from birth are required to choose one after reaching adulthood or risk losing their Japanese nationality [1]. Those acquiring Japanese nationality are also required to renounce other nationalities if possible [2, Article 5]. I know someone who was born in the Soviet Union and, after living in Japan for many years, became a Japanese citizen. She had problems renouncing her previous citizenship because the country where she was born no longer existed; she said she had to bribe someone at the Russian Embassy to get the necessary documentation. She also mentioned being detained and questioned when trying to enter Canada on her Japanese passport for a short stay because the Canadian immigration officials thought she didn’t look Japanese. She had no similar difficulties when trying to enter Japan itself. [1] http://www.moj.go.jp/ENGLISH/information/tcon-01.html http://www.moj.go.jp/ENGLISH/information/tcon-01.html [2] http://www.moj.go.jp/ENGLISH/information/tnl-01.html http://www.moj.go.jp/ENGLISH/information/tnl-01.html