Japan's Supreme Court Could Make History for Same-Sex Marriage

Tokyo's streets just pulsed with rainbow flags and techno beats for Tokyo Rainbow Pride, a vibrant backdrop to a legal battle that’s been quietly brewing for years. Japan's Supreme Court is on the verge of a decision that could redefine marriage, and LGBTQ+ communities are not-so-quietly pushing for equal rights with one clear message: “May love prevail in the Supreme Court.”

The Long Road to Equality

The court is weighing whether Japan's current Civil Code, which conveniently forgets about same-sex marriage, actually violates the Constitution. The legal world expects a ruling by early 2027, which, if you think about it, is both a long wait and a blink of an eye for a decision this monumental.

This whole saga kicked off on Valentine’s Day, 2019, when thirteen same-sex couples decided enough was enough and sued the government across five different cities. Fast forward to March 2024, and the Sapporo High Court dropped a bombshell, ruling that excluding same-sex couples from forming families was, in fact, unconstitutional. Four other high courts agreed, citing violations of equality, the pursuit of happiness, and individual dignity. You know, those pesky things written right there in the Constitution.

Then, because nothing is ever simple, a Tokyo High Court in November 2025 decided to be the outlier. It ruled that the Constitution’s definition of marriage didn't include same-sex couples and that any changes should come from Japan’s National Diet (their parliament). Legal scholar Yasuhiko Watanabe wasn’t having it, pointing out that this ruling would hand “unchecked discretion to the conservative government.” So, with an assist from the group Marriage for All Japan, the plaintiffs took their fight to the Supreme Court.

Japan's Unique Stance

Here’s the kicker: Japan is currently the only G7 nation without national legal protections or marriage rights for same-sex couples. Let that sink in for a moment.

Public opinion, however, tells a different story. Polls in 2023 showed a solid majority—65% in a conservative poll, 72% in a liberal one—support same-sex marriage. Yet, Prime Minister Sanae Takaichi and her ruling Liberal Democratic Party (LDP) remain firmly opposed. During her September 2025 election campaign, Takaichi declared, “I am fundamentally opposed to same-sex marriage. The Constitution defines marriage as being between a man and a woman. Therefore, at this time I do not support same-sex marriage.” Because apparently, that's where we are now.

Currently, same-sex couples miss out on spousal benefits baked into over 100 laws, from insurance to pensions. They have to rely on regional partnership systems, which started in Tokyo in 2015 and now exist in over 500 regions. These offer limited, non-binding perks like hospital visitation rights – a nice gesture, but hardly full equality.

The government has tried to respond, recognizing registered same-sex couples as having “de facto marriage status” in some laws and even passing an LGBTQ+ Understanding Law in 2023. They even launched their first national awareness plan recently. But as Yasuhiko Watanabe noted, this “de facto marriage” approach through partnership systems is a recipe for “symbolic segregation,” creating a “second-class” stigma if only heterosexual couples can actually marry.

Crucially, even with partnership registration, same-sex couples can't enter the national household registration system, called Koseki. This system is the backbone of Japanese family life, tracking lineage under one surname. Without it, same-sex couples are locked out of automatic inheritance, spousal tax deductions, spousal visas, and child adoption. Conservative lawmakers in the National Diet resist changing marriage law precisely because they fear it would unravel the Koseki system, potentially impacting hundreds of other civil and nationality laws. It’s a bit like pulling one thread and fearing the whole sweater will unravel.

Can Love Really Win?

Activists see the Supreme Court’s decision to bring these disputes to the 15-Justice Grand Bench as a huge deal. It could finally break a decade of political stagnation. If the Grand Bench rules the current marriage law unconstitutional, it might just force the National Diet to get to work rewriting marriage and Koseki systems. Or, perhaps, create a separate civic union registration system. The least desirable outcome? The court punts, following the Tokyo High Court’s lead and letting the National Diet decide how to protect sexual minorities' equal rights, which hasn't exactly been a speedy process so far.

Since May 2026, Marriage for All Japan has been running a nationwide “Love Wins” campaign, aiming to plaster “May love prevail in the Supreme Court” across all 47 prefectures during Pride Month. Because sometimes, a little public pressure is exactly what a high court needs.