Japan Prince Akishino wants emperor 'age limit' debate
Prince Akishino, who is second in line to the Japanese imperial throne, has called for debate on whether a retirement age should be set for the country's head of state.
His remarks come days after his father, Emperor Akihito, was released from hospital after treatment for pneumonia.
The prince urged the Imperial Household Agency to "flexibly deal with" his 77-year-old father's work load.
He made the comments at a news conference to mark his 46th birthday.
"When you pass a certain age, it gradually becomes difficult for people to do various things," Prince Akishino said.
He called for "more discussion" on establishing a retirement age for the emperor.
Emperor Akihito plays a largely ceremonial role but is respected deeply by many Japanese.
He spent almost three weeks in hospital earlier this month. He also had surgery for prostate cancer in 2003 and suffered stress-related health issues in late 2008.
In 2009 the royal agency said he would cut back on official duties such as speeches and meeting foreign dignitaries.
Under Japan's 1947 Imperial House Law, the emperor is succeeded on his death by a male relative.
Crown Prince Naruhito is first in line to the throne, followed by his younger brother Prince Akishino.
Women cannot inherit the Japanese throne and so Princess Aiko, the daughter of Crown Prince Naruhito, cannot succeed her father.
Third in line to the throne is Prince Hisahito, Prince Akishino's son.