一世一元

Japanese

Kanji in this term
一	世	一	元
いち > いっ Grade: 1	せい Grade: 3	いち Grade: 1	げん Grade: 2
goon	kan'on	goon	kan'on

 一世一元の制 on Japanese Wikipedia

Examples
In China, the Hongwu era started and ended with the reign of Emperor Hongwu In Korea, the Gwangmu era started and ended with the reign of Emperor Gwangmu In Vietnam, the Bảo Đại era started and ended with the reign of Emperor Bảo Đại In Japan, the Reiwa era started and will end with the reign of Naruhito, who will be known posthumously as Emperor Reiwa

Etymology

Probably ultimately from Middle Chinese 一世一元 (MC 'jit syejH 'jit ngjwon, literally “one generation, one era”), as this practice originated in China. Also analyzable in Japanese as a compound of 一世 (issei, “one generation”) +‎ 一元 (ichigen, “one era”).^[1][2][3][4]

First cited in Japanese to 1868.^[1]

Pronunciation

• (Tokyo) いっせーいちげん [ìsséé íchíꜜgèǹ] (Nakadaka – [6])^[4][5]
• IPA^(key): [isːe̞ː it͡ɕiɡẽ̞ɴ]

Noun

一(いっ)世(せい)一(いち)元(げん) • (issei ichigen) 

1. [from 1868] (monarchy) an East Asian practice of dating, using exactly one distinct era name for each monarch's reign, where such era name also eventually becomes the monarch's posthumous name

References

1. “一世一元”, in 日本国語大辞典 [Nihon Kokugo Daijiten]‎ (in Japanese), concise edition, Tokyo: Shogakukan, 2006
2. “一世一元”, in デジタル大辞泉 [Digital Daijisen]‎ (in Japanese), Tōkyō: Shogakukan, updated roughly every four months
3. Shinmura, Izuru, editor (1998), 広辞苑 [Kōjien] (in Japanese), Fifth edition, Tokyo: Iwanami Shoten, →ISBN
4. Matsumura, Akira, editor (2006), 大辞林 [Daijirin] (in Japanese), Third edition, Tokyo: Sanseidō, →ISBN
5. NHK Broadcasting Culture Research Institute, editor (1998), NHK日本語発音アクセント辞典 [NHK Japanese Pronunciation Accent Dictionary] (in Japanese), Tokyo: NHK Publishing, Inc., →ISBN