Japan's Marriage Equality Fight Reaches the Top: Six Cases, One Grand Bench, One Ruling to Come

Japan is the only country in the Group of Seven that does not legally recognize same-sex couples — not through marriage, not through civil unions, not in any nationwide form. That fact has held for years while the rest of the G7 moved on. It is now, finally, in front of the one court that can change it.

In late March 2026, Japan’s Supreme Court accepted six separate appeals challenging the country’s ban on same-sex marriage and referred all of them to its Grand Bench — the full 15-justice panel the court reserves for cases of major constitutional significance. Routine appeals are decided by smaller petty benches. Sending something to the Grand Bench is the Japanese judiciary’s way of saying: this one matters, and we intend to settle it.

How the cases got here

The six appeals are the surviving threads of a wave of lawsuits filed across Japan beginning in 2019, when couples in multiple cities sued the national government, arguing that excluding them from marriage violates the constitution. The relevant text is Article 24, which describes marriage as based on “the mutual consent of both sexes,” and Article 14, which guarantees equality under the law.

The district and high courts that heard those cases did not agree with each other. Several lower courts found the marriage ban unconstitutional or in a “state of unconstitutionality,” reasoning that the absence of any legal framework for same-sex couples cannot be squared with the equality guarantee. The outlier came on November 28, 2025, when the Tokyo High Court issued the only appellate ruling to find the ban constitutional.

That split is precisely why the Supreme Court stepped in. When high courts reach opposite conclusions on the same constitutional question, the country is effectively operating under two different versions of its own constitution depending on the jurisdiction. Only the Supreme Court can collapse that into a single answer, and only the Grand Bench can do it with the authority to bind everything below.

What the ruling can and cannot do

It is important to be clear about the mechanics, because they shape what a win would actually mean.

Even if the Grand Bench finds the current situation unconstitutional, the Supreme Court cannot itself write marriage equality into law. Japan’s system leaves that to the Diet, the national legislature. What a ruling of unconstitutionality would do is place enormous, sustained pressure on lawmakers to act — the judicial branch formally telling the legislative branch that the status quo violates the nation’s founding document. Japan has precedent for the Diet responding to that kind of pressure, though rarely quickly.

A decision is expected in 2027. That timeline is frustrating for couples who have already spent years in court, but a Grand Bench reference is also the strongest procedural signal the case has received to date.

The gap between the law and the country

One reason this case carries weight is that Japanese law has fallen conspicuously behind Japanese society.

National polling has shown majority public support for marriage equality for several years. More tellingly, the country has built a sprawling, unofficial workaround from the bottom up: hundreds of municipalities and prefectures — covering the large majority of Japan’s population — now issue local “partnership” certificates to same-sex couples. Those certificates carry real social recognition and unlock some local services, but they are not marriage. They do not confer inheritance rights, spousal status for immigration, parental rights, or the tax and medical-decision protections that come automatically with a marriage license. A couple can be recognized by their city hall and remain legal strangers to the national government.

That patchwork is both encouraging and an argument for the plaintiffs: it demonstrates that recognizing same-sex couples has caused none of the social disruption opponents predicted, and it underlines that only the national framework — the one the Supreme Court is now examining — can close the gaps that matter most.

Why it matters beyond Japan

For LGBTQ+ people across Asia, the Japan case sits inside a larger and genuinely mixed regional picture. Taiwan legalized same-sex marriage in 2019. Thailand’s marriage equality law took effect in January 2025 and has since registered tens of thousands of marriages. Nepal’s courts have moved toward recognition. Against those gains sit real setbacks elsewhere in the region, including rollbacks of trans recognition.

A favorable ruling from Japan’s highest court would be the most consequential marriage equality development in Asia since Thailand — not only for the couples directly involved, but as a signal from one of the region’s most influential democracies and the world’s fourth-largest economy.

For now, the wait continues. Six cases, fifteen justices, one bench, and a ruling that will not arrive until 2027. But after years in which Japan’s marriage equality movement advanced city by city while the national government stood still, the question has finally reached the only room in the country where it can be answered for everyone at once.