Since 1873, Japan's official New Year has followed which calendar?

Since 1873, Japan’s official New Year has followed the Gregorian calendar.

The change took place during the Meiji period, when Japan rapidly reorganized its institutions along modern administrative and international lines. The government replaced the traditional Japanese lunisolar calendar with the Gregorian system, making January 1 the official New Year date. The transition was abrupt: the final day of 1872 was followed by January 1, 1873.

Before the reform, Japanese New Year was celebrated on the first day of the first month in a lunisolar calendar. Because that calendar tracked both lunar months and solar seasons, New Year usually fell sometime between late January and February by modern Gregorian reckoning.

The calendar change did not erase every older custom. Japan still preserves New Year practices such as hatsumōde, the first shrine or temple visit of the year, nengajō greeting cards, osechi foods, and traditional decorations. In the Ryukyu Islands, traditional lunisolar New Year observances also continue in some communities.