What calendar does the solar term belong to?

Twenty-four solar terms, a supplementary calendar to guide farming in ancient China, were formed in the Spring and Autumn Period and the Warring States Period. Because the lunar calendar in China is a kind of "yin and yang calendar", which is based on the movement of the sun and the moon, it can't fully reflect the solar cycle. But China is an agricultural society, and agriculture needs a strict understanding of the movement of the sun, so farming is entirely based on the sun. Therefore, the "twenty-four solar terms" that reflect the solar cycle alone are added to the calendar as the standard for determining leap months. Twenty-four solar terms can reflect the changes of seasons, guide agricultural activities and affect the food, clothing, housing and transportation of thousands of families. The twenty-four solar terms are divided according to the position of the sun on the ecliptic (that is, the orbit of the earth around the sun).

Some people think that the 24 solar terms are subordinate to the lunar calendar, but they are actually defined according to the solar calendar. That is, according to the position of the sun on the ecliptic, a year is divided into 24 equal parts. That is to say, the ecliptic is divided into 24 equal parts, each equal part accounts for 15 of the ecliptic. Because the time required for the sun to pass through each bisection is almost equal, the Gregorian calendar dates of the 24 solar terms are roughly the same: the first half of the year is around 6 and 2 1, and the second half is around 8 and 23. And there are two formulas: 621 in the first half of the year and 823 in the second half. In ancient times, solar terms were called "qi", and there were two qi in each month: the former was called "solar terms" and the latter was called "neutral qi". The monthly distribution of the 24 solar terms is shown in the following table, which is closely related to the arrangement of the lunar leap month. In the lunar calendar, beginning of spring is the first of the 24 solar terms. The names of the 24 solar terms are named according to the place pointed by Dougang and the natural climate and landscape at that time. The so-called fighting means that the three stars of the Big Dipper, Kuixing, Xingxing and Yuxing, point to different directions and positions with the movement of celestial bodies, and the positions they refer to are the months they represent. For example, the first month is cloudy, dusk refers to cloudy, midnight refers to cloudy, and daytime refers to cloudy. February is the base, at dusk, at midnight, during the day, and so on.