Naomi Osaka chooses Japanese Citizenship for 2020 Tokyo Olympics. The tennis star has decided to represent Japan over the U.S. in the upcoming games. Osaka, who was born in Japan but raised in the U.S., holds dual citizenship to both countries. Japan requires those with dual citizenship to relinquish one before turning 22. I think I will be able to put more of my emotion into it by playing for the pride of the country. , Naomi Osaka, via NHK. The 2020 Summer Olympics kick off on July 24