Japan's "Freedom of Marriage for All" same-sex marriage unconstitutionality lawsuits have experienced two years of intense turbulence. Since the Sapporo High Court set a precedent in 2024 by ruling that the non-recognition of same-sex marriage is "unconstitutional," high courts across the country gradually reached a consensus on its unconstitutionality. However, a reversal by the Tokyo High Court at the end of 2025, which ruled it "constitutional," disrupted this trend and sparked division within the judicial system. In response to strong appeals from the plaintiffs, the Supreme Court officially decided on March 25, 2026, to merge the cases for review before the Grand Bench, composed of all 15 justices. This historic decision means that Japan's highest judicial body will soon issue a final ruling on the constitutional legitimacy of same-sex marriage, directly reshaping the country's future parliamentary legislation and the progress of equal rights.