Prince Hisahito is first Japanese male royal to reach adulthood in 40 years

Japan’s Prince Hisahito is celebrating his 19th birthday on Saturday, becoming the first male royal in the country to reach adulthood in 40 years.

Given the imperial family’s dwindling numbers, he could also be the last.

The elaborate palace rituals to formally recognise Hisahito as an adult on Saturday are a reminder of the bleak outlook for the world’s oldest monarchy.

Much of this comes down to its male-only succession policy and dwindling numbers.

Hisahito is second-in-line to the Chrysanthemum Throne and is likely to become emperor one day. He is the nephew of Emperor Naruhito.

After him, however, there is nobody left, leaving Japan’s Imperial family with a dilemma over whether they should reverse a 19th century ruling that abolished female succession.

A first-year at Tsukuba University near Tokyo, Hisahito studies biology and enjoys playing badminton.

He is especially devoted to dragonflies and has co-authored an academic paper on a survey of the insects on the grounds of his Akasaka estate in Tokyo.

In his debut news conference in March, the prince said he hopes to focus his studies on dragonflies and other insects, including ways to protect insect populations in urban areas.

Hisahito was born on September 6 2006, and is the only son of Crown Prince Akishino, the heir to the throne, and his wife, Crown Princess Kiko.

He has two older sisters, the popular Princess Kako and former Princess Mako, whose marriage to a non-royal required her to abandon her royal status.

Hisahito’s coming-of-age rituals fall a year after he turned 18, reaching legal adulthood, because he wanted to concentrate on college entrance exams.

He is the nephew of Emperor Naruhito, who has one child, a daughter, Princess Aiko. Hisahito’s father, Akishino, the Emperor’s younger brother, was the last male to reach adulthood in the family, in 1985.

Hisahito is the youngest of the 16-member all-adult Imperial Family. He and his father are the only two male heirs who are younger than Naruhito. Prince Hitachi, former Emperor Akihito’s younger brother, is third-in-line to the throne, but is 89 years old.

The shortage of male successors is a serious concern for the monarchy, which historians say has lasted for 1,500 years. The issue reflects Japan’s rapidly aging and shrinking population.

Japan traditionally had male emperors, but female succession was permitted. There have been eight female emperors, including the most recent Gosakuramachi who ruled from 1762 to 1770. None of them, however, produced an heir during their reign.

Succession was legally limited to males by the pre-war Constitution for the first time in 1889. The post-war 1947 Imperial House Law, which largely preserves conservative pre-war family values, also only allows male succession.

But experts say the male-only succession system is structurally flawed and only worked previously thanks to the help of concubines who, until about 100 years ago, produced imperial children.

Hugely popular Princess Aiko, the only daughter of Emperor Naruhito and Empress Masako, cannot be her father’s successor, even though she is supported by much of the public as a future monarch.

To address succession concerns, the government compiled a proposal to allow a female emperor in 2005. But Hisahito’s birth quickly changed the tide and nationalists turned against the proposal.

A separate, largely conservative panel of experts in January 2022 recommended calling on the government to maintain its male-line succession while allowing female members to keep their royal status after marriage and continue their official duties.

The conservatives also proposed adopting male descendants from now-defunct distant royal families to continue the male lineage.

But the debate has stalled over the question of whether to give royal status to non-royals who marry princesses and their children.