Japanese eras, known as gengō, are periods in Japan's history defined by the reign of an emperor. Each era begins with the ascension of a new emperor and ends with their death or abdication. The name of the era reflects the emperor's reign and often symbolizes the hopes or aspirations of the time. The current era, Reiwa, began in May 2019 with the ascension of Emperor Naruhito. Prior to Reiwa, the Heisei era lasted from 1989 to 2019. These eras help historians and the public understand the cultural and political changes that occurred during specific periods in Japan's history.