TOKYO -- Japan's emperor sent an unprecedented signal Monday of his desire to abdicate and hand over power to his son, sending the country into constitutionally uncharted waters.
In a video address to the nation -- only the second time an emperor has spoken to the people in this way -- 82-year-old Akihito described how his declining health was curtailing his abilities to fulfill his duties.
"When I consider that my fitness level is gradually declining, I am worried that it may become difficult for me to carry out my duties as the symbol of the state with my whole being as I have done until now," Akihito said in the address Monday. The first time he had recorded an address to the public was after the 2011 tsunami, which claimed almost 20,000 lives.
Under the U.S.-drafted constitution imposed on Japan after World War II, the emperor was stripped of all his powers, becoming a figurehead only. He is legally constrained from saying anything political, meaning that Akihito could not declare his intention to step down because that would require the parliament to amend the Imperial Household Law.
Akihito expressed concern that when an emperor who falls ill or dies, Imperial Family tradition calls for "events of heavy mourning, continuing every day for two months, followed by funeral events which continue for one year.
"These various events occur simultaneously with events related to the new era, placing a very heavy strain on those involved in the events, in particular, the family left behind," he said. "It occurs to me from time to time to wonder whether it is possible to prevent such a situation."
Hirohito, the World War II-era emperor, died of a protracted illness at age 87; Akihito was 55 when he succeeded his father. His oldest son, Naruhito, is 56.
Palace doctors regularly announced Hirohito's declining health condition, and the public responded by canceling festivals and other events. Some even postponed weddings.
Akihito sent a clear message that he wants to pass over his duties to his son, Crown Prince Naruhito, saying that simply making him a regent, as legally allowed, would not be sufficient.
"In coping with the aging of the emperor, I think it is not possible to continue reducing perpetually the emperor's acts in matters of state and his duties as the symbol of the state," Akihito said, according to an official English translation of his remarks, which were aired on NHK, the public broadcaster. But having a regent would "not change the fact that the emperor continues to be the emperor till the end of his life, even though he is unable to fully carry out his duties as the emperor."
Prime Minister Shinzo Abe said he took Akihito's comments Monday seriously.
"I think we have to thoroughly think what we can do to accommodate his concerns, taking into consideration the emperor's age and the current burden of official duties," Abe said.
Akihito clearly does not want to do only half the job, analysts say, and carefully parsed his words so as to convey this.
"He must have been in such a tough situation to come to make this statement, because he's well aware that he shouldn't be making any political comments," said Yuji Otabe, a professor of Japanese history at Shizuoka University of Welfare. "He wants to protect the law, but he also has physical limits. He wanted everyone to understand his current situation."
Professor Hidehiko Kasahara of Keio University said that the emperor was trying to express his personal desire to retire without saying the word "abdicate."
"He sent out a strong message that he'd like to hand over to his successor and wants him to stably continue the duties as the symbol of the state," he said. "Since he doesn't hold any right to get involved into politics, he chose this way to talk about his opinion as an individual. And that must have reached people's hearts very heavily."
Akihito has been on the Chrysanthemum Throne for 28 years, since the death of his father, Hirohito, who ruled Japan throughout the wartime period. Akihito, who has previously signaled that he supports the pacifist constitution imposed on Japan after the war, is the only emperor to have been sworn in under it and is widely viewed as opposed to prime minister Shinzo Abe's intention to loosen some of the postwar shackles imposed on Japan.
Abe's government will now have to decide how to proceed, and even if it does decide to change the laws, the process could take years, experts said.
Toshihiko Saito of Gakushuin University, author of the book Emperor Akihito and Pacifism, said the government "can't ignore his intention but must act on his words."
Japanese media reports said the government may consider enacting a special law allowing Akihito's abdication that would not be applicable to his successors, because debate over a revision of the Imperial House Law could take too much time since it is likely to reignite debate over whether to allow female emperors and other divisive issues.
Naruhito has a daughter, and his younger brother has two daughters and a son, Prince Hisahito, the only male in the youngest royal generation. Hisahito's birth, in 2006, put an end to the debate about female monarchs, at least for the time being. But with so few males in the family, experts say the succession is far from secure for the future.
Akihito's announcement Monday was not a surprise. He has had health issues -- prostate cancer and heart problems -- and, marking his birthday in December, he said there had been times when he had felt his age.
Then, last month, NHK reported that he wanted to abdicate, although the Imperial Household Agency denied the report. Some analysts thought that the government had leaked the information as a "trial balloon" to test the public response to the unprecedented idea.
Polls have since shown that the public is supportive, with between 77 percent and 90 percent of respondents saying the government should create a system to allow the emperor to abdicate.
"We speak respectfully about the emperor, but arguably we use him like a slave," said Daisuke Kodaka, 34, an employee at a cosmetics company in Tokyo. "He's our symbol, but as a person he doesn't have human rights. We should recognize his rights."
Japan has had centuries of emperors -- surviving eras of powerful samurais and shoguns and wars -- who were considered to be divine as they were said to be direct descendants of Amaterasu, the Shinto goddess of the sun. Today, however, the emperor serves as a unifying figurehead.
Abdication was relatively common until 1817, when Kokaku became the last emperor to resign his post. No provision for abdication was included in the constitutional and legal changes following Japan's surrender at the end of World War II.
Information for this article was contributed by Anna Fifield of The Washington Post; by Mari Yamaguchi, Ken Moritsugu and staff members of The Associated Press; and by Jonathan Soble of The New York Times.
A Section on 08/09/2016