In a big milestone for Japan's royal family, Prince Hisahito turned 18 on Friday, becoming the first male royal family member to reach adulthood in almost four decades.
It is a significant development for a family that has ruled for more than a millennium but faces the same existential problems as the rest of the nation a fast-aging, shrinking population.
Hisahito, who is set to become the emperor one day, is the nephew of Japanese Emperor Naruhito. His father, Crown Prince Akishino, was the last to do so, in 1985.
Hisahito is the youngest of the 17-member all-adult imperial family, which currently has only four men.
His status as the last heir apparent poses a major problem for a system that doesn't allow empresses. The government is debating how to keep succession stable without relying on women.
The 1947 Imperial House Law, which largely preserves conservative pre-war family values, only allows a male to succeed to the throne and forces female royal members who marry commoners
