Li: Jian Shi also means that spring, summer, autumn and winter begin from this point on. Beginning of Spring is the first solar term among the twenty-four solar terms. It is the first day of the year in the Ganzhi calendar and the first day of the Jian Yin month. The arrival time is on February 3-5 of each year in the Gregorian calendar, when the sun reaches 315° celestial longitude.
The date of Beginning of Summer on the lunar calendar is not fixed, it is around the first day of April every year, so the lunar calendar is a lunisolar calendar. "Dou points to the southeast, and the dimension is the beginning of summer. All things grow up here, so it is called the beginning of summer."
The beginning of autumn is the 13th solar term in the twenty-four solar terms, and it is the end of the last month of the Ganzhi calendar. and the beginning of Shen Yue. The time is around the first day of July in the lunar calendar (between August 7-9 in the Gregorian calendar).
"Autumn" means the end of summer and the beginning of autumn. At the beginning of autumn, the sycamore trees begin to lose their leaves, hence the idiom "falling leaves tell us about autumn".
The Beginning of Winter is the nineteenth of the twenty-four solar terms and one of the traditional festivals of the Han nationality. It is the end of the Xu month and the beginning of the Hai month in the Ganzhi calendar. The time point is between November 7 and 8 of each year in the Gregorian calendar, that is, the sun is located at 225° of ecliptic longitude.