Prince Akishino has said the country should look to setting a retirement age for its emperor, just days after his increasingly frail father was discharged from a lengthy hospital stay.
The younger son of the royal couple, who is second in line to the throne, was voicing a rare public opinion to reporters ahead of his own 46th birthday.
"I think it will become necessary," he said, when asked by a reporter to comment on an idea of setting a retirement age for Japanese emperors.
The comment, published in the Japanese press on Wednesday, came after his 77-year-old father, Akihito, resumed public duties following a 19-day stay in hospital, where he was treated for bronchial pneumonia and fever.
"When you pass a certain age, it gradually becomes difficult for people to do various things. I think it is an idea" to set a retirement age, Akishino said, calling for "more discussion" of the issue.
Japan's royals rarely comment on public or political matters, including those touching on the affairs of their own cloistered family.
But Akishino's remark comes as Japan is exploring ways to maintain the staid household in modern times.
Akishino's son, Hisahito, 5, is the first male born to the imperial family since Akishino himself, a cause for concern among traditionalists who support the male-only succession rule.
Since being stripped of his semi-divine status in the aftermath of World War II, Japan's emperor has played a largely ceremonial role in public life as the titular head of state, but is held in deep respect by his people.
Akihito's wife, Empress Michiko also expressed concern last month about failing health, but said she stands beside the emperor while listening to the advice of physicians.
Akihito underwent surgery for prostate cancer in 2003, and still receives treatment.
The emperor did not attend a welcome ceremony this month for the visiting king and queen of Bhutan, the first time he has missed a meeting with a state guest since he ascended to the throne in 1989 following the death of his father Hirohito.© AFP