When did the division of the twenty-four solar terms begin to appear? According to what?

During the Qin and Han Dynasties, the 24 solar terms were completely established and divided. In BC 104, the taichu calendar written by Deng Ping in the Han Dynasty officially set 24 solar terms in the calendar, and defined the astronomical position of the 24 solar terms.

According to the available data, the 24 solar terms may occur at the end of the Warring States Period. Although all the names of the twenty-four solar terms only appeared in Huainanzi Astronomical Training in the Western Han Dynasty, most of the names of the twenty-four solar terms were recorded in Lv Chunqiu at the end of the Warring States Period.

According to the law of the operation of heaven and earth, the ancients determined the starting point and ending point of the four-season cycle and divided the 24 solar terms. The trajectory of the sun in a year is divided into 24 equal parts, each of which is a "solar term", collectively called "twenty-four solar terms". Twenty-four solar terms represent twenty-four different positions of the earth in the orbit of revolution.

Because it takes 365 days for the earth to go around the sun, there is a solar term every fifteen days, and each solar term represents different changes in climate, phenology and time. The spring rain shakes the spring and clears the valley, and the summer is full of mountains and summers. Autumn dew, autumn frost, little snow in winter and cold in winter. The solar term song, which is well known to China people, implies the order of the 24 solar terms.

Extended data

The 24 solar terms are: winter solstice, slight cold, severe cold, beginning of spring, rain, fright, vernal equinox, Qingming, Grain Rain, long summer, xiaoman, Miscanthus, summer solstice, slight summer heat, great summer heat, beginning of autumn, early summer heat, white dew, autumnal equinox, cold dew, early frost, beginning of winter, light snow and heavy snow.

Twenty-four solar terms are generally accepted by the public in China, and their influence can be seen everywhere in daily life. Some solar terms combine with folk culture and become fixed festivals for people. The most famous Tomb-Sweeping Day, beginning of spring, Changxia and Solstice in winter are all integrated into the festive atmosphere. Solstice in summer and Solstice in summer are also closely linked with daily life, so that there is a folk saying that "three days in winter and three days in summer". These festivals are usually accompanied by colorful folk activities.

The intangible cultural heritage of the 24 solar terms is very rich, including related proverbs, songs, legends, traditional production tools, household utensils, handicrafts, paintings and other works of art, as well as festival culture, production ceremonies and folk customs closely related to the festival. Twenty-four solar terms are the concrete expression of ancient agricultural civilization in China, which has high research value of agricultural history and culture.

Baidu encyclopedia-24 solar terms