Japan has taken a landmark step towards non-binary legal recognition.

The Osaka High Court ruled on 8 May that the country’s family registration system, the koseki, a mandatory national record-keeping system tracking births, deaths and marriages, violates Japan’s constitutional equality protections by only offering “male” and “female” as gender options.

The case was brought by a 50-year-old non-binary resident of Kyoto Prefecture, who petitioned to change their designation of “eldest daughter” to a gender-neutral term in the koseki.

While the court stopped short of granting the individual request immediately, it ruled that the absence of a nonbinary gender marker option should be reconsidered at a national level and that if such an option is introduced, the petitioner’s case should be revisited.

The court went further, stating that gender identity is “directly linked to an individual’s personal existence, making it a significant legal good.”

Attorney Shun Nakaoka, who has worked on non-binary recognition cases in Japan, called it “a huge step toward legal recognition,” noting that until now “the existence of nonbinary gender has been legally unrecognised” in Japanese law.

The ruling does not immediately change the system, but it sets a constitutional precedent that advocates say could pave the way for reform across the country.