The Nationalist Party of China in the 1920s adopted the Gregorian calendar. This is the group that the communists overthrew and they retreated to Taiwan in 1949

The Nationalist Party of China in the 1920s adopted the Gregorian calendar. This is the group that the communists overthrew and they retreated to Taiwan in 1949/50. The communists never changed back... so the Chinese calendar is only used for traditional chinese events (like the chinese new year). This is part of the period in china known as the Century of Humiliation (1839-1949)... which includes the invasions of western powers, opium wars, etc.