Adoption of the Gregorian calendar Julian to the Gregorian calendar. For example, in the article "The October (November) Revolution" the "Encyclopædia Britannica" uses the format of "25 October (7 November, New Style)" to describe the date of the start of the revolution. Other countries of eastern Europe, most notably Eastern Orthodox countries, adopted the Gregorian calendar in the 1910s or early 1920s. The last country of Eastern Orthodox Europe to adopt the Gregorian calendar for civil purposes was Greece, at the time under military administration following the 11 September 1922 Revolution, with Wednesday 15 February 1923 being followed by Thursday 1 March 1923. The Soviet
Adoption of the Gregorian calendar the old style calendars were similar but not all the same. The Arabic numerals may be used for both calendar dates in modern Japanese and Korean languages, but not for Chinese old-style dates. Japan started using the Gregorian calendar on 1 January 1873, locally known as . The preceding day, 31 December 1872, was . Japan currently uses two eras: the western era and a modified traditional Japanese era name (nengō). The months and days are those of the Gregorian calendar, but the year is either the western year number or a year of the nengō of the emperor on