Japanese eras
their names and periods

Modern Japan

There have been five eras since the Meiji Restoration, and each new emperor has brought a new era. The first day of an era restarts the count of the Japanese year (nengō). The first year continues until the next Gregorian calendar's New Year, at which time, the nengō second year begins.

For example, when Crown Prince Naruhito ascended the throne as the 126^th Emperor of Japan on 1 May 2019, that day marked the beginning of the Reiwa era - Reiwa 1. On 1 January 2020, the year became Reiwa 2.

Emperor Naruhito succeeded his father Emperor Akihito, who abdicated on 30 April 2019. This meant that 2019 was Heisei 31 between 1 January - 30 April, and Reiwa 1 between 1 May - 31 December.

This also meant that calendar printers were quite busy in 2019, preparing 2020 calendars, since the era name was a closely guarded secret until 1 May.

Pre-Meiji

Emperor Meiji oversaw many changes in Japan. Between 645 and 1868, each reign covered several era names, often to coincide with inauspicious years in Onmyō.