Japanese imperial year
The Japanese imperial year (皇紀 kōki?) or "national calendar year" is a unique calendar system in Japan. It is based on the legendary foundation of Japan by Emperor Jimmu in 660 BC. Kōki emphasizes the long history of Japan and the Imperial dynasty.
Kōki dating was used as early as 1872, shortly after Japan adopted the Gregorian calendar system.
- The IJA's Type 92 battalion gun was called "ninety-two" because its design was completed in 1932, and the 2592nd year since the first Emperor of Japan was 1932 (Kōki 2592).
- The Mitsubishi A6M Zero was called the "Zero" because it entered service in 1940 (Kōki 2600).
- Japan's wartime cipher machine was named the System 97 Printing Machine for European Characters.
The Proclamation of Indonesian Independence used the imperial year.
- Nussbaum, Louis-Frédéric. (2005). "Kigen" in Japan Encyclopedia, p. 514.
- Gubbins, John Harrington. (1922). The Making of Modern Japan, p. 71; Mossman, Samuel. (1873). New Japan, the Land of the Rising Sun, p. 462.
- Chamberlain, Bail Hall. (1905). Things Japanese, p. 478; Goodrich, John King. (1913). Our Neighbors: the Japanese, p. 61.
- 神武天皇即位紀元二千五百三十三年明治六年太陽暦 (1872)
- Ruoff, Kenneth J. (2001). The People's Emperor: Democracy and the Japanese Monarchy, 1945-1995, p. 268 n52.
- Organizing Committee of the XIIth Olympiad. (1940). Report of the Organizing Committee on its Work for the XIIth Olympic Games of 1940 in Tokyo until its Relinquishment, pp. 174-175 (PDF 198-199 of 207); retrieved 2012-2-21.
- Lacroix, Eric. (1997). "Table A.2. Japanese Dates," Japanese cruisers of the Pacific War, p. 700.
- Nussbaum, "Calendar" at pp. 98-99.