On January 1, 1873, Japan adopted the Gregorian calendar. Before 1873, the Chinese style lunisolar calendar had been in use since 7th century.Japanese eras are still in use.

Japan has refused to accept some elements of the Gregorian calendar itself. The present Japanese Solar calendar does not include following events:

The Northward equinox is a national holiday in Japan and an important religious holiday in both Japanese Buddhism and Shinto but is determined completely using astronomy. The date is not fixed but is announced by National Astronomical Observatory of Japan every year.

Sunday and Saturday are regarded as "Western style take-a-rest days". Many Japanese retailers do not close on Saturdays or Sundays, because many office workers and their families are expected to visit the shops during the weekend. An old Japanese imperial navy song says "We have neither Sundays nor Saturdays!" which means "We work throughout the week."

Leap years in the Japanese solar calendar have been legally determined based on kōki since 1899, however this law sets the number "kōki-660" to be the base of calculation, so leap years in Japanese solar calendar are aligned with that of the Gregorian calendar.