Japan adopts the Gregorian calendar

Background. Prior to 1873, Japan's official calendar was based on the lunisolar Chinese calendar, which began 3 to 7 weeks later than the Gregorian system. This traditional system influenced cultural concepts such as lucky and unlucky days and the meanings behind month names. The transition to the Gregorian calendar marked a significant shift in how time was officially recorded and celebrated in Japan.

Meiji Calendar Reform. The Western Common Era system, based on the solar Gregorian calendar, was introduced in 1873 as part of the Meiji period modernization. This reform established the Gregorian calendar as the official reference for dating, and it was first used in the official calendar that year. Japan continues to use the Gregorian calendar together with year designations stating the year of the reign of the current Emperor.

Cultural Persistence. Despite the official adoption of the Gregorian calendar, the influence of the previous lunisolar system remains visible in modern Japanese calendars. Concepts such as lucky and unlucky days and the traditional meanings of month names persist. Since 1876, January has been officially regarded as the first month for setting dates of traditional folklore events.