Emperor Akihito, Japan's 82-year-old monarch, plans to step down in the coming years, according to reports from doemstic broadcaster NHK, citing government sources.

Such a move would be a first in modern Japanese history. Emperor Kokaku was the last Japanese monarch to abdicate the throne back in 1817.

Akihito ascended to the throne in 1989, following the death of his father, Emperor Hirohito.

Akihito's health has been deteriorating in recent years. He underwent heart surgery in 2012, and was treated for prostate cancer in 2003. In between, he was hospitalized for two weeks, in 2011, with bronchitis.

A later report from the Kyodo news agency quoted the vice grand steward of the Imperial Household Agency, Shinichiro Yamamoto, seeking to quash the rumors: "I know there are media reports about this, but it is definitely not true," Yamamoto said. However, Kyodo had previously reported, citing government sources, that Akihito had been telling those in his inner circle of his plans for about a year.

The emperor has been trimming back his imperial duties, handing off more and more of them to his son, Crown Prince Naruhito. The 56-year-old prince is heir to the throne.

Japan fought World War II in the name of Hirohito. But Akihito has devoted a great deal of energy towards healing those war wounds during his time on the throne.

A legacy of pacifism

Last year he marked the 70th anniversary of the end of the second world war by expressing "deep remorse" for Japan's aggression.

"Looking back at the past, together with deep remorse over the war, I pray that this tragedy of war will not be repeated and together with the people express my deep condolences for those who fell in battle and in the ravages of war," he said.

Akihito's father was a controversial figure, but Akihito "was the first post-war emperor to embrace the [pacifist] constitution and his role as a symbol of national unity," said Koichi Nakano, a political science professor at Sophia University in Tokyo.

"He cares a great deal about war issues and reconciliation [with Asian countries]. Naruhito has made clear that he will carry on with that," Nakano said.

The Imperial Household Law would need to be amended to allow Akihito to step down, a process that could take time and parliamentary debate, according to Miiko Kodama, a professor emeritus at Musashi University.

Japan's postwar constitution stripped the emperor of all political power, leaving him "the symbol of the State and of the unity of the People."

Akihito sought to create a "middle-class monarchy" by creating the image of a royal family drawn closer to the people.

bik/msh (Reuters, dpa)