Because this is the first time in the history of Japanese constitutionalism to be replaced by abdication, the period of abdication and reform is decided by the Japanese government. In order to make New Year's Day "widely accepted", the Japanese government needs to take into account the opinions of the Palace Office and the Liberal Democratic Party.
At the same time, the current Emperor Akihito will "abdicate before his death" on April 30, Crown Prince Naruhito will become the new emperor on May 1, and the New Year's number "Linghe" will be officially opened at 0: 00 that day. From then on, the "Heisei" era from 1989 to 1 will be withdrawn from the historical stage in only 1 month.