Today the Supreme Court rules on an archaic law—unique among developed countries—which bars married couples from keeping separate surnames. Almost all married women take their husband’s name, not vice versa. Five women have sued the state, saying that this violates constitutional guarantees of sexual equality. Yet many people (including many politicians of the conservative ruling party of Shinzo Abe, the prime minister) insist that letting women keep their names would weaken family ties. The top court will also rule on a second 19th-century restriction on women, which mandates a six-month break between divorce and remarriage to avoid doubts about paternity—a rule that DNA testing makes especially outdated. If the top court declares the restrictions unconstitutional, optimists will see this as a signal of better times for women under Mr Abe; others will note how much ground Japan still needs to catch up.