11 February is National Foundation Day, a national holiday for Japanese people to remind themselves of the nation's founding and foster their love for the nation.
It marks the traditional date on which according to legend Emperor Jimmu founded Japan in 660 BC
Japan switched from the traditional Japanese calendar - a lunar calendar based on the waxing and waning of the moon - to the Gregorian calendar starting in January 1873.
It was at this time that the day of the enthronement of Emperor Jinmu, the first Japanese emperor, was made a national holiday and named Kigen-setsu. 11 February 660 BC was determined as the day of enthronement by calculating the date in the solar calendar corresponding to the date recorded in the Chronicles of Japan, Japan's first history compiled on imperial orders.
However, many historians now believe that Emperor Jinmu's enthronement, as described in the Chronicles, was probably not a historical fact but merely folklore.
Before World War II , governmental offices and schools across Japan held many celebrations on Kigen-setsu, but after the war, the holiday was abolished for several reasons.
However, there were so many compliants about the removal of the holiday that in 1966 the day was reinstated as a national holiday, renamed as National Foundation Day.