A Japanese court on Thursday rejected a lawsuit challenging the country's ban on its citizens from holding foreign nationality, in what is believed to be the first judicial decision on the matter.
In a lawsuit filed with the Tokyo District Court in 2018, eight men and women in their 30s to 80s who were born in Japan but now live in Europe claimed a legal requirement that Japanese who gain foreign nationality must give up their citizenship violates the Constitution.
The government, however, argued the plaintiffs' claim takes no note of national interests, as permitting dual citizenship would enable people to have voting rights or diplomatic protection in other countries.
Dual citizenship "could cause conflict in the rights and obligations between countries, as well as between the individual and the state," said Presiding Judge Hideaki Mori.
According to the suit, the eight plaintiffs -- six who have acquired Swiss or Liechtenstein nationality and two others who plan to obtain Swiss or French nationality to facilitate their work and lives -- hope to maintain their Japanese citizenship.
Article 11 of the nationality law states that Japanese citizens who acquire non-Japanese nationality on their own instigation automatically lose their Japanese nationality, effectively banning dual citizenship.
The plaintiffs claimed that the law was originally designed for purposes such as avoiding overlapping military service obligations imposed by multiple nations.
"The court did not seriously consider the feelings of Japanese living abroad," Swiss resident Hitoshi Nogawa, 77, who led the plaintiffs, said following the ruling.
As many countries in the world, including the United States, now allow dual citizenship, the clause stripping people of Japanese nationality violates the Constitution, which guarantees the right to pursue happiness and the equality under the law, the plaintiffs said.
The issue of dual nationality in Japan drew global attention when tennis superstar Naomi Osaka, who had both Japanese and U.S. citizenship, selected Japanese nationality just before turning 22 in 2019. She was born to a Japanese mother and Haitian father.
The law requires those who acquired dual nationalities under 20 years old to choose one by age 22, and those who obtained them at age 20 or older to select one within two years.
The nationality law also requires Japanese citizens who obtain foreign citizenship to notify the government of their abandonment of Japanese nationality. But as it includes no penalties, many Japanese are believed to have maintained multiple passports after obtaining non-Japanese citizenship.
About 518,000 Japanese are estimated to have permanent residency status in other countries as of October 2019, but the government has been unable to confirm how many of them hold multiple citizenship.