Japanese era years on documents, and how they convert
Japanese official documents date themselves by era year. 令和6年 is a year within the Reiwa era, not a year on any calendar a reader elsewhere uses, and the conversion is simple arithmetic once the era's first year is known.
These are the five eras that appear on documents still in circulation, with the exact day each began — because that date is what makes the boundary years awkward.
| Era | Romaji | Short | First day | Conversion |
|---|---|---|---|---|
| 令和 | Reiwa | R | 2019-05-01 | Reiwa n = 2018 + n |
| 平成 | Heisei | H | 1989-01-08 | Heisei n = 1988 + n |
| 昭和 | Showa | S | 1926-12-25 | Showa n = 1925 + n |
| 大正 | Taisho | T | 1912-07-30 | Taisho n = 1911 + n |
| 明治 | Meiji | M | 1868-10-23 | Meiji n = 1867 + n |
Two things catch people out. The first year of an era is written 元年 and never 1年. And because an era begins mid-year, one Gregorian year can carry two era names: January to April 2019 is 平成31年, May onward is 令和元年, and both are correct.