Who was the first Japanese emperor to abdicate since 1817?

Akihito (born 23 December 1933) is a member of the Imperial House of Japan who reigned as the 125th emperor of Japan, according to the traditional order of succession, from 1989 until 2019, Heisei era. He succeeded to the Chrysanthemum Throne upon the death of his father, Emperor Showa (Hirohito). Upon abdication due to his age and declining health, he became emperor emeritus. He was succeeded by his oldest son, Naruhito.

After 30 years on the Chrysanthemum Throne, Emperor Akihito of Japan abdicated on 30 April 2019, being the first Japanese emperor to do so since 1817. This marked the end of the Heisei era and the inception of the Reiwa era, and saw numerous festivities leading up to the accession of his son and successor, Emperor Naruhito. The enthronement ceremony took place on 22 October 2019. Akihito's younger son, Prince Akishino, is his brother's heir presumptive.