What is the lunar calendar?

lunar calendar, commonly known as lunar calendar, yin calendar, ancient calendar and old calendar, refers to the summer calendar traditionally used in China. The Xia calendar is one of the six ancient calendars in China. It is said that the calendar was founded in the Xia Dynasty. The original calendar rules have been lost. Now we only know some contents from some ancient books: taking the month of the winter solstice as the sub-month as the calendar year, the calendar year starts with the establishment of Yinyue, that is, Yin Zheng (later called Xia Zheng), which roughly adopts an integer of 366 days as one year, and uses subtraction method and positive leap surplus to adjust the time difference.

China's traditional calendar, which is now known as the summer calendar, was called the summer calendar after the adoption of the western calendar in the Revolution of 1911. Some people thought that the traditional calendar in China was in the summer, so it was called the summer calendar. In fact, the basic rule of this traditional calendar used now is to follow the Han calendar (taichu calendar) formulated by the Han Dynasty, so it should be called the Han calendar. At present, it is also called lunar calendar, lunar calendar, ancient calendar and old calendar. It belongs to a kind of lunar calendar, and the average calendar month is equal to a new moon, which is the same as the lunar calendar principle, so it has the component of lunar calendar; On the other hand, leap months are set to make the average calendar year a tropical year, and 24 solar terms are set to reflect the changing characteristics of seasons (the annual movement of the direct point of the sun), so there is also a solar calendar. Up to now, almost all Chinese in the world, as well as countries such as the Korean Peninsula and Vietnam, still use the summer calendar (Han calendar) to calculate traditional festivals such as Spring Festival, Mid-Autumn Festival and Dragon Boat Festival.

The summer calendar is different from the Yin calendar, the weekly calendar and the Qin calendar, mainly in which month is taken as the beginning of the year. There are twelve months in a year, which are divided into sub-month, ugly month, Yinyue, Uzuki, Chenyue, Mitsuki, noon month, non-month, Shenyue, Youyue month, Moon (note: it's not guarding) and Haiyue month. The month of the winter solstice of Zhongqi (the mid-winter month) is the sub-month, the month of the great cold (the winter month) is the ugly month, and the month of the rain (the month of Meng Chun) is the Yinyue Yu and so on. The first month of the summer calendar is Yinyue (the same as the first month of the present Han calendar (so-called lunar calendar), the first month of the Yin calendar is Ugly Moon (equivalent to December of the present Han calendar (so-called lunar calendar), and the first month of the week calendar is Ziyue (equivalent to November of the present Han calendar). The first month of the Qin calendar is the month of the sea (equivalent to October of the present Han calendar (the so-called lunar calendar)). For example, March in the summer calendar is April in the lunar calendar and May in the weekly calendar. Since the beginning of Emperor Wu of Han Dynasty, Xia Zheng has been adopted. In this way, future generations mistakenly think that the current calendar is the summer calendar, but in fact it is just Xia Zheng.