How to determine the division principle of 24 solar terms and winter 19293949,, and?

Twenty-four solar terms divide the earth into 24 equal parts around the sun. (If you look at the calendar, you can find that the dates of the 24 solar terms invented by the ancients in China are relatively fixed on the Gregorian calendar invented by Europeans. It's no coincidence that they are compiled based on the period of the earth's revolution around the sun. )

The reason why there are 24 solar terms is that the cycle of the China lunar calendar is one month, which is about 29.5 days. The period of the earth's revolution around the sun is about 365.25 days.

Obviously, the two are inseparable. The way of Lunar New Year is to add a leap month in a certain year (a whole month, instead of only adding 1 day in February like the Gregorian calendar), otherwise we will wear shorts and undershirts to watch the Spring Festival Evening before long. However, the growth of crops is obviously more closely related to sunshine and temperature than the moon. If the sowing date of crops is determined according to the lunar calendar, it will obviously have a negative impact on the harvest of crops. So the ancients invented the twenty-four solar terms. In this way, farmers can decide the arrangement of farming according to the relative date with the 24 solar terms.

As for the number nine, it should be related to the ancient people's worship of the largest single digit nine.