This is info taken from a wikipedia page. To go to the full page click on this link: Wikipedia - Japanese eras
The List of Japanese eras is a traditional calendar system which began during the reign of Emperor Kōtoku in the 7th century. This calendar has been in use in Japan since the beginning of the 8th century.
The historical Japanese calendar system defines and parses time in terms of ordinal numbers.
Each new Japanese era (nengō, lit. "year name") was usually started soon after the beginning of the reign of a new emperor. Era names were also changed due to other events. Staring in the reign of Emperor Yōzei, the tradition of naming eras because of good omens changed. Instead, the name of an era might be chosen to ward off something bad.
The first day of the first year of a nengō (gannen) started whenever the emperor decided. This first year continued until the next lunar new year, which is understood to be the start of the nengō's second year.
To change a Japanese year to a Western or Gregorian
calendar year, find the first year of the nengō (see
list below). When found, subtract 1, and add the number of the Japanese
year. For example, the 23rd year of the Shōwa period (Shōwa
23) was 1948:
ILLUSTRATION: 1926 - 1 = 1925 and then 1925 + 23 = 1948 ... or Shōwa 23.
|CONVERSION TABLE: Gregorian calendar years / nengō|
|江戸 Edo period|
|1624||Kan'ei||Empress Meishō, 1629-1643; Emperor Go-Kōmyō, 1643-1654.|
|1652||Jōō||also Shōō; Emperor Go-Sai, 1655-1663.|
|1655||Meireki||also Myōryaku or Meiryaku|
|1661||Kanbun||Emperor Reigen, 1663-1687.|
|1684||Jōkyō||Emperor Higashiyama, 1687-1709.|
|1704||Hōei||Emperor Nakamikado, 1709-1735.|
|1711||Shōtoku||Emperor Go-Momozono, 1771-1779.|
|1716||Kyōhō||Emperor Sakuramachi, 1735-1747.|
|1744||Enkyō||Emperor Momozono, 1747-1762.|
|1751||Hōreki||also Hōryaku; Empress Go-Sakuramachi, 1762-1771.|
|1764||Meiwa||Emperor Go-Momozono, 1771-1779.|
|1772||An'ei||Emperor Kōkaku, 1780-1817.|
|1781||Tenmei||also a "popular expression meaning 'difficulty'"|
|1789||Kansei||from Sui Dynasty phrase, "When conducting government, do so with lenience"|
|1804||Bunka||Emperor Ninkō, 1817-1846.|
|1830||Tenpō||also Tenhō; name links with Tenna and Kyōhō|
|1844||Kōka||Emperor Kōmei, 1846-1867.|
|1868||明治||Meiji||Emperor Meiji, 1868-1912. Also known as "Enlightened Government" or "Brilliant Rule"|
|1912||大正||Taishō||Emperor Taishō, 1912-1926.|
|1926||昭和||Shōwa||Emperor Shōwa, 1926-1989.|
|2019||令和||Reiwa||Naruhito, 2019-present [the reigning emperor].|