Experts on a government-commissioned panel in Japan have held their first meeting to study how to accommodate Emperor Akihito's apparent abdication wish.
Unlike many European countries where abdication of kings and queens are relatively common, Japan's modern imperial law does not allow abdication, and Japan's post-war constitution stipulates the emperor as a mere "symbol" with no political power or say.
Allowing Emperor Akihito to abdicate would be a major change to the system, and raises a series of legal and logistical questions, ranging from laws subject to change to the emperor's post-abdication role, his title and residence.
The six panel members - five academics and a business organisation executive - are to compile a report early next year after interviewing specialists on the constitution, monarchy and history.
Emperor Akihito, 82, suggested his wish to abdicate in a rare video message to the public in August, citing his age and concern that he may not be able to fulfil his official duties.
His message was subtle and the emperor did not use the word "abdication", because saying that openly could have violated his constitutional status.
Current law, set in 1947, largely inherits a 19th century constitution that banned abdication as a potential risk to political stability.
About 80% of the public supports Emperor Akihito's abdication, saying he should be allowed to retire and enjoy life while he is still in good health.
In addition to receiving foreign dignitaries, Emperor Akihito still travels across the country to attend ceremonies and has repeatedly visited disaster-hit areas to console survivors.
The government reportedly wants to allow Emperor Akihito's abdication as an exception and enact a special law to avoid dealing with divisive issues such as possible female succession and lack of successors.
Emperor Akihito suggested in his public message a need to consider how to make the succession process smoother.
He recalled the difficulties he faced when his father, Hirohito, died in 1989 while he was largely serving as a substitute.
He said he does not wish to cling to his title if his responsibilities have to be severely reduced and he has to rely on a regent.
The abdication issue has also renewed concerns about ageing and a shortage of successors in the 2,000-year-old monarchy, reflecting the overall concern about Japan's declining and rapidly ageing population.
Emperor Akihito and his wife, Michiko, have two sons - Crown Prince Naruhito and his younger brother, Akishino - as first and second in line to the Chrysanthemum throne. The couple have four grandchildren but only one - Akishino's son - is eligible to become emperor under Japan's male-only succession system.
Prime minister Shinzo Abe said at the outset of the meeting that he hopes the discussion is carried out thoroughly because it is "an extremely important issue that affects the basis of our country".