THE progenitor of Japan’s imperial line, supposedly 2,600 years ago, was female: Amaterasu, goddess of the sun. But for most of the time since, all emperors have been male. This has exercised the UN’s Committee on the Elimination of Discrimination against Women. Recently it concluded that Japan should let women inherit the Chrysanthemum throne, too.

It is not clear what Emperor Akihito, who is 82 (and has a hugely popular wife), thinks about this. But the Japanese prime minister blew his top. Shinzo Abe leapt to the defence of a male-only line, saying it was rooted in Japanese history. The panel’s meddling, he said, was “totally inappropriate”. Cowed, it withdrew its recommendation that the law of succession be changed.

Polls suggest that most Japanese would welcome a female monarch. A decade ago a looming succession crisis triggered a robust discussion, led by Junichiro Koizumi, then prime minister and Mr Abe’s political mentor, on whether to allow a woman to ascend the throne. But the birth of Hisahito, a boy prince, ended the debate. A draft law was quietly shelved.

Mr Abe does not share Mr Koizumi’s iconoclasm. An arch-traditionalist, he wants the male-only system preserved to protect the imperial bloodline. But in other ways he has been an unlikely champion of diversity since he came to power (for the second time) in 2012. He has cajoled Japanese firms into promoting more women and urged them to make it easier for them to come back to work after having children.

There is a long way to go. Japan is bottom of the rich world in most rankings of sexual equality. For the past month Mr Abe has struggled with the political fallout from a much-read blog post by a working mother angry at a chronic shortage of day-care places. Still, Mr Abe’s efforts appear to be getting somewhere. From April big companies will have to declare their plans for promoting women. The hope is that this will shame firms that overlook female talent. As for the proportion of board members who are women, it has inched up by a percentage point in the past year—to 2.7%.

The UN committee notes this progress but laments foot-dragging on other issues. Japanese women are still meant to need spousal consent for abortions, it says, even in cases of rape. Divorced women must wait months before remarrying thanks to an archaic rule designed to remove uncertainty over the paternity of unborn children. For most Japanese women, the question of whether or not some future princess can become empress is hardly pressing. But Yoko Shida, a constitutional scholar, says it matters nonetheless. It is, she says, a symbol of discrimination.