National Foundation Day (建国記念の日, kenkoku kinen-no-hi^?) is a national holiday in Japan celebrated annually on February 11.^[1] On this day, Japanese celebrate the founding of the nation and the imperial line by its legendary first emperor, Jimmu, who according to legend established his capital in Yamato in 660 BC.^[2]

The origin of National Foundation Day is New Year's Day in the traditional lunisolar calendar. On that day, the foundation of Japan by Emperor Jimmu was celebrated based on Nihonshoki (日本書紀), which states that Emperor Jimmu ascended to the throne on the first day of the first month.