Ten same-sex couples will jointly file a suit against the government next February for not recognizing marriage equality, their lawyers said Friday.
The couples argue that the government's position on same-sex marriage flouts equality under the law and freedom of marriage as protected in the Japanese Constitution.
The couples, who are seeking compensation, will file the suit in district courts throughout the country, including Tokyo and Nagoya.
Article 24 of the Constitution says, "Marriage shall be based only on the mutual consent of both sexes."
The government has indicated that it interprets this to apply only to heterosexual couples while the lawyers working for the couples argue that some legal scholars do not see it as prohibiting same-sex marriage.
The government also argues that the term "husband and wife" used in the civic law and the family registration law indicates a man and a woman, and thus cannot accept marriage applications from gay and lesbian couples.
Marriage equality has already been legalized in other parts of the world. The Netherlands was the first to do so in April 2001, followed by other European nations. Taiwan will be the first in Asia to join them next May.
"We want our call to be widespread so that the freedom to marry will be recognized for everyone," said Shinya Maezono, one of the lawyers.