Read the era name
Identify 明治, 大正, 昭和, 平成, or 令和. Do not infer the era from metal or design alone.
Meiji through Reiwa
Japanese Coin Era-Date Guide
Convert and validate Meiji, Taisho, Showa, Heisei, and Reiwa coin dates, including the first-year gannen convention.
Conversion model
Gregorian year = era year + offset. 元年 means the first year, not year zero. Transition-year coins still need the era characters because two eras can share one Gregorian year.
| Era | Japanese | Boundary | Offset | Examples |
|---|---|---|---|---|
| MeijiMeiji | 明治 · めいじ | 1868 – 1912-07-29 | +1867 | 明治4年 = 1871; 明治元年 = 1868 |
| TaishoTaishō | 大正 · たいしょう | 1912-07-30 – 1926-12-24 | +1911 | 大正元年 = 1912 |
| ShowaShōwa | 昭和 · しょうわ | 1926-12-25 – 1989-01-07 | +1925 | 昭和元年 = 1926 |
| HeiseiHeisei | 平成 · へいせい | 1989-01-08 – 2019-04-30 | +1988 | 平成元年 = 1989 |
| ReiwaReiwa | 令和 · れいわ | 2019-05-01 – present | +2018 | 令和元年 = 2019 |
Read the era year
元年 is year 1. Other years may use Japanese numerals, modern digits, or stylized forms.
Apply the offset
For example, Showa 39 is 39 + 1925 = 1964; Heisei 31 and Reiwa 1 both fall in 2019.
Validate the type
The converted year must also fit the identified design generation. Conversion cannot repair a misread era or a mismatched coin.
This foundation validates Meiji coin years using the 1868 year and offset. It does not assert a proleptic Gregorian start day for pre-Gregorian historical dating.
Evidence
Sources and scope
These links support the claims on this page. Source authority does not imply permission to republish source images.
Taisho, Showa, Heisei, and Reiwa transition dates.
Open sourceLegal basis for changing modern era names upon imperial succession.
Open sourceAncient through modern chronology, Tokugawa tri-metallic system, Kanei Tsuho, koban, Meiji yen transition.
Open source