As it stands, the fate of the Japanese imperial family rests on 12-year-old Hisahito, the son of Crown Prince Naruhito's younger brother and the last eligible male heir.
Japan's centuries-old succession would be broken if Hisahito does not have a male child as the Imperial Household Law, in place since 1947, does not allow women to ascend the Chrysanthemum Throne.
That means Naruhito's only child, 17-year-old Princess Aiko, is not in line to inherit the throne.
While public attitudes seem to be shifting to change the succession laws to allow women to rule, the chance of concrete reform looks remote.
According to a poll by the Yomiuri Shimbun daily between October and November, nearly two-thirds want the law revised to allow women to be the rightful heir.
"I just wonder why Princess Aiko cannot ascend the throne," Mizuho, a Tokyo resident in her 30s who only gave her first name, told AFP.
"If it's just because she's a girl, then I think it's out of place in the current era," she said.
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