Japan's New Year was originally the same as China's, based on the lunar calendar, hence many of the festivals were also similar. However, during Japan's Meiji Restoration Period, in an effort to learn from the West and fully westernize, the Meiji Government abolished the traditional lunar calendar in favor of the Western Gregorian calendar.
China, on the other hand, adopted the Gregorian calendar in 1912, the year after the Xinhai Revolution, although it was used alongside the lunar calendar. After the establishment of New China, this dual calendar system was retained, and the Chinese people remained more accustomed to the traditional Lunar New Year.
Of course, this also meant that the Chinese New Year was different from that of the vast majority of countries around the world.
Since Japan adopted the Gregorian calendar for its New Year, the holiday occurs on New Year's Day.
