Chinese calendar by mountain peoples. After Qin Shi Huang unified China under the Qin dynasty in 221 BC, the Qin calendar () was introduced. It followed most of the rules governing the Zhuanxu calendar, but the month order was that of the Xia calendar; the year began with month 10 and ended with month 9, analogous to a Gregorian calendar beginning in October and ending in September. The intercalary month, known as the second "Jiǔyuè" (), was placed at the end of the year. The Qin calendar was used into the Han dynasty. Emperor Wu of Han introduced reforms halfway through his
Adoption of the Gregorian calendar Japan decided to officially replace its traditional lunisolar calendar with the Gregorian calendar in 1872, so the day following the second day of the twelfth month of the fifth year of the Meiji emperor's rule, became . (The Japanese rendering of the Western months is simply "ichi-gatsu" or "One-month" for January, "ni-gatsu" or "Two-month" for February, etc.) This brought Japan's calendar in alignment with that of the major Western powers (excluding Russia). To this day, however, it is common to use Nengo, reign names instead of the Common Era or Anno Domini system, especially for official documents; for instance, "Meiji"