The Japanese government is considering holding Emperor Akihito's abdication ceremony at the Imperial Palace on April 30, 2019 as a state occasion, government sources said Monday.

The emperor, who is scheduled to retire on that day at the age of 85, will be the first Japanese monarch to step down in more than 200 years. His elder son Crown Prince Naruhito is set to ascend the throne the following day.

The government is considering how to stage the first abdication ceremony in modern Japan without conflicting with the Constitution that prohibits the emperor from having political power. Under the supreme law, which took effect in 1947, the emperor, once considered divine, is defined as "the symbol of the state."

Emperor Akihito wishes to abdicate in a ceremony that is "as simple as possible," partly because an enthronement ceremony for the crown prince will be held a few months later, according to the Imperial Household Agency's Grand Steward Shinichiro Yamamoto.

There will be no foreign dignitary guests or parade and the emperor will not appear before the general public at the palace for a farewell greeting, he said.

The government will set up an organization headed by Chief Cabinet Secretary Yoshihide Suga in January to prepare for a spate of ceremonies based on traditional rituals. The last monarch who abdicated was Emperor Kokaku in 1817.

One of the upcoming events is "Kenji-to-Shokei-no-gi" -- a ceremony to hand down to the new emperor the sacred sword and jewels of the Imperial Regalia, as well as the Privy Seal and the State Seal.

Emperor Akihito's enthronement ceremony was held on Nov. 12, 1990, following the death of his father Hirohito, posthumously known as Emperor Showa, in January 1989. It was attended by about 2,200 guests including foreign heads of state.

The enthronement ceremony was organized as a state act in accordance with the Imperial House Law that stipulates imperial matters. But the law lacks a provision on an abdication ceremony.

The Imperial Household Agency also said Monday the retired emperor and empress will move to a palace in Tokyo's Akasaka Estate, where the crown prince and his family currently live, after it has been renovated.

The residence for the retired emperor will be called Sento gosho, while the new emperor and his family will live in the Imperial Palace, according to the agency.

The emperor, who has had heart surgery and undergone treatment for prostate cancer, said in a rare video message aired in August 2016 that he is concerned age would one day stop him from fulfilling his duties, understood as him expressing his wish to retire.

Japan's parliament enacted a one-off law in June this year to allow the emperor to pass the throne on to the crown prince.