The Agency says the event will be held three days after Crown Prince Naruhito ascends to the throne on May 1. Emperor Akihito is due to abdicate on April 30.
The Agency had initially planned to hold the celebratory event after a ritual scheduled for October 22 to proclaim the new Emperor’s enthronement.
But it decided it would be more appropriate to celebrate the enthronement shortly after it takes place.
The Agency decided the new date will make it easier for people to attend the event, as May 4 falls during a 10-day holiday period.
The new Emperor, accompanied by the new Empress and other family members, is to appear on the balcony of the Imperial Palace that day. The Emperor will also address the expected crowds of well-wishers.
Emperor Akihito and Empress Michiko will not attend the event.