What is the relationship between the 24 solar terms and leap month?

Ancient historians in China divided the 24 solar terms into solar terms and neutral terms, which were arranged alternately. Among them, the singular solar terms are beginning of spring, Jingzhe, Qingming, Changxia, Mangzhong, Xiaoshu, beginning of autumn, Bailu, Hanlu, beginning of winter, Daxue and Xiaohan. Even numbers are neutral gases, namely, rain, vernal equinox, Grain Rain, Xiaoman, summer solstice, great summer heat, early summer heat, autumn equinox, early frost, light snow, winter solstice and great cold.

The lunar calendar takes 12 as the symbol of1February, that is, every month has a certain amount of neutral gas, such as rain in the first month, vernal equinox in February and so on.

In ancient times, there were different arrangements for the lunar leap month, but since the Han Dynasty, a leap method has gradually formed, calling the lifeless month the leap month of the previous month. As I said just now, there is a certain amount of qi corresponding to it every month. Why is there no gas for a month? This question is not difficult to understand. Because there are 24 solar terms in a tropical year, it means that the average between solar terms or neutral gas and neutral gas is (365.2422÷ 12=)30.4368 days, and a new moon is 29.5306 days, which is nearly one day apart, so the date of neutral gas (with the same solar terms) in the lunar month is backward every month. In the long run, there will always be a phenomenon that gas rushes to the end of the month, so there will be no gas next month, and there is still a solar term left. So this neutral month is called this year's leap month, and it is called the name of last month, but a leap is added before the month. For example, the date of neutral gas in the first seven months of 1979 (the lunar calendar is the last year) is: there is no neutral gas in leap June here, only one solar term-beginning of autumn.