Japanese Imperial year (皇紀 kōki) or "National calendar year" is a unique calendar system in Japan. It is based on the legendary founding of Japan by Emperor Jimmu in 660 BC.
Kōki emphasizes the long history of Japan and the Imperial dynasty.
The Summer Olympics and Tokyo Expo were planned as anniversary events in 1940 (Kōki 2600); but the international games were not held because of the Second Sino-Japanese War.
The Imperial Japanese Army (IJA) and Imperial Japanese Navy (IJN) used the Kōki system for identification. For example,
- 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).
In Japan today, the system of counting years from the reign of Emperor Jimmu has been abandoned.
- ↑ 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.
- ↑ 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.