About "Twenty-four solar terms and solar calendar". . .

China used the lunar calendar in ancient times.

The month of the lunar calendar is determined according to the moon phase cycle and belongs to the lunar calendar.

But the lunar calendar couldn't help farmers in ancient times, so the ancient working people formulated 24 solar terms according to the revolution of the earth around the sun, which is the solar calendar.

The lunar calendar is the lunar calendar (lunar calendar+solar calendar)

Besides, the solar calendar is not new in modern times. Calendars can be divided into three categories: lunar calendar, solar calendar and yin-yang calendar. In modern times, there are some Gregorian calendars, which we use now, such as week, year, month, day and so on. Gregorian calendar is a kind of solar calendar.