What are the main features of ancient astronomical calendars in China?

Lunar calendar is a traditional calendar in China, also known as Xia calendar, Han calendar, Hua calendar, national calendar and so on. It is a kind of lunar calendar. Take the cycle of the moon phase as the length of the month and the year when the sun returns as the age. By setting leap months, the average calendar year can adapt to the year when the sun returns. According to the rule of China's ancestor Xuanyuan the Great, this year is the Year of the Monkey (47 BC13).

There are many records about the lunar calendar in ancient books and Oracle Bone Inscriptions, and a large number of historical records record that the lunar calendar began in the era of the Yellow Emperor. It is generally believed that the calendar rule of the integration of yin and yang in the lunar calendar originated from the Shang Dynasty.