Editorial: Add calendar authority for Japanese Imperial era names #79
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ptomato
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Sep 4, 2025
spec.emu
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| <tr> | ||
| <td>*"japanese"*</td> | ||
| <td>Japanese Imperial calendar, era system hybridised with *"gregory"*. Month numbers, month codes, and days are the same as in the ISO 8601 calendar, extended proleptically before their introduction in ISO year 1873. Imperial era names only extend as far back as the Meiji period (starting in ISO year 1868) during which calendar reforms took place. The arithmetic year, and the years and eras before ISO year 1868, are identical to *"gregory"*.</td> | ||
| <td>Japanese Imperial calendar, era system hybridised with *"gregory"*. Month numbers, month codes, and days are the same as in the ISO 8601 calendar, extended proleptically before their introduction in ISO year 1873. Imperial era names only extend as far back as the Meiji period (starting in ISO year 1868) during which calendar reforms took place. All era names are defined by the Japanese government. The arithmetic year, and the years and eras before ISO year 1868, are identical to *"gregory"*.</td> |
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Maybe "Modern era names are defined..."? (The decision to use era names only since 1868 is JS's concession to practical implementation concerns, and bce/ce are not defined by the Japanese government)
sffc
reviewed
Sep 18, 2025
spec.emu
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| <tr> | ||
| <td>*"japanese"*</td> | ||
| <td>Japanese Imperial calendar, era system hybridised with *"gregory"*. Month numbers, month codes, and days are the same as in the ISO 8601 calendar, extended proleptically before their introduction in ISO year 1873. Imperial era names only extend as far back as the Meiji period (starting in ISO year 1868) during which calendar reforms took place. The arithmetic year, and the years and eras before ISO year 1868, are identical to *"gregory"*.</td> | ||
| <td>Japanese Imperial calendar, era system hybridised with *"gregory"*. Month numbers, month codes, and days are the same as in the ISO 8601 calendar, extended proleptically before their introduction in ISO year 1873. Imperial era names only extend as far back as the Meiji period (starting in ISO year 1868) during which calendar reforms took place. All era names are defined by the Japanese government. The arithmetic year, and the years and eras before ISO year 1868, are identical to *"gregory"*.</td> |
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CLDR defines the era names, which are transliterations of the ones defined by the government of Japan, which defines both the eras and their cutoff dates.
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ben-allen
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Updated to reflect that CLDR, rather than the Japanese government, is the authority for era name transliterations. Retitled as editorial, since I believe t doesn't change any observable requirements. |
ptomato
approved these changes
Oct 1, 2025
Manishearth
approved these changes
Oct 1, 2025
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Filed #86 as a follow-up, since it would be scope creep in this already-reviewed PR. |
eras are as defined by CLDR
authority for era ranges.
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Updated to reflect outcome of discussion in 2025-10-09 TG2 |
sffc
approved these changes
Oct 13, 2025
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Added wording specifying that Japanese Imperial era names are defined by the Japanese government.
See The Historical Background of How Japan Chooses Its Era Names. Key quote:
Also see description of the Japanese Imperial calendar system used in documentation for Java's JapaneseEra class: