The basis of the 24 solar terms?

Qi is a precious scientific heritage created by Chinese ancestors after thousands of years of practice, and it is a tool to reflect the changes of weather, climate and phenology and master the farming season.

As early as the Spring and Autumn Period and the Warring States Period, China was able to measure the length of the sun's shadow at noon with a soil gauge (a pole was erected on the plane), thus determining four solar terms: winter solstice, summer solstice, vernal equinox and autumn equinox. In a year, the shortest day of the noon soil return shadow is the summer solstice, the longest day is the winter solstice, and the shadow with moderate length is the vernal equinox or autumn equinox. The Book of History in the Spring and Autumn Period recorded the solar terms. The twenty-four solar terms are completely recorded in Huainanzi written by Liu An in the Western Han Dynasty. In ancient China, the lunar calendar was used to record time, and the solar calendar was used to divide the 24 solar terms of spring, summer, autumn and winter. Our ancestors called five days 1, and three days were called solar terms. The whole year was divided into 72 days out of 24 solar terms.

With continuous observation, analysis and summary, the division of solar terms is gradually enriched and scientific. By the Qin and Han dynasties more than 2000 years ago, a complete concept of 24 solar terms had been formed.

In ancient times, a year was divided into twelve months, and each month had two solar terms. The former is solar terms, while the latter is neutral. For example, beginning of spring is the first month's festival, and it rains in the first month. Later generations called solar terms and neutral gas solar terms.

The names of the 24 solar terms are: beginning of spring, Rain, Sting, Vernal Equinox, Qingming, Grain Rain, Changxia, Xiaoman, Mangzhong, Summer Solstice, Xiaoshu, beginning of autumn, Chushu, Bailu, Autumnal Equinox, Cold Dew, Chufrost, beginning of winter, Light Snow, Winter Solstice, Slight Cold and Severe Cold.

/ziliao/2004-02/06/content _ 13025 12 . htm