Since 1868, when Japan switched rulers from a shogun to an Emperor, there have been four reigning Emperors: Meiji, Taisho, Hirohito (Showa), and Akihito (Heisei). Japan's traditional era is based on the emperor's reign. This table shows the era year and the Gregorian calendar equivalent. Note that in a transition year, it becomes the last year of the preceding era as well as the first year of the new era.

Currently it is the Heisei Era. To calculate its Gregorian calendar equivalent, just add 88. For example, Heisei 10 is '98 (1998). For a Showa year, add 25.

To postcard collectors: Often times, the era name is not mentioned in the postmark. You will have to use other identity points to determine the year. For example, 14.7.6 could be July 6, 1881 or 1925 or 1939. In most cases, it is easy to determine the proper year.