Origin of the 24 Solar Terms

The 24 Solar Terms is a supplementary calendar used to guide agricultural activities, which was established in the pre-Qin Dynasty and fully established in the Han Dynasty. It is a system of knowledge formed by observing the annual movement of the sun and recognizing the changing patterns of the seasons, climate, and physical phenomena in a year.

It divides the annual movement of the sun into 24 equal parts, each of which is a festival, starting from the first day of spring and ending with the last day of cold, and the cycle begins again and again, which is not only a time guideline enacted by the officials of successive dynasties, but also a compass for guiding the agricultural production, and a compass for people to foretell the coldness, warmth and snow in their daily life, which is the fruit of the accumulation of the long-term experience of the Han Chinese laboring people and the crystallization of their wisdom.

In ancient China, the use of sundials measured sundials, the longest annual shadow as "to" (also known as the longest day to, long to, winter solstice), the shortest shadow for the "short day to" (also known as the short solstice, summer solstice). In the spring and fall each day of equal length of day and night, it is designated as the "spring equinox" and "autumn equinox". During the Shang Dynasty, there were only four solar terms, but during the Zhou Dynasty there were eight, and during the Qin and Han Dynasties, the 24 solar terms were fully established. In 104 B.C., the Tai Chu Calendar, which was developed by Deng Ping and others, formalized the twenty-four solar terms in the calendar and clarified the astronomical positions of the twenty-four solar terms.

The name of the twenty-four solar terms was first mentioned in the Western Han Dynasty in Huainanzi - Tianwenxun, and the concepts of yin and yang, the four seasons, the eight positions, the twelve degrees, and the twenty-four solar terms were also mentioned in the "Discussion on the Essentials of the Six Families" in the "Historical Records of China" (史记 - Taishigong Ziyuan). During the reign of Emperor Wu of the Han Dynasty, Lokei compiled the solar terms into the Tai Chou Calendar, and stipulated that the month without a solar term would be designated as an intercalary month of the previous month.

The 24 solar terms (二十四节气) refer to the 24 specific seasons in the Chinese lunar calendar that represent the change of seasons, and are based on the change of the Earth's position on the ecliptic (i.e., the Earth's orbit around the Sun), with each corresponding to a certain position reached by the Earth for every 15° of movement on the ecliptic.

2. Significance

The twenty-four solar terms are not only the time guidelines issued by the government, but also the compasses for guiding agricultural production, and the compasses for people to foretell the cold, warmth, snow and rain in daily life. The 24 solar terms accurately reflect the changes of the seasons and are used to guide agricultural activities, affecting the clothing, food, housing and transportation of thousands of families. The 24 solar terms scientifically reveal the laws of astronomical and meteorological changes.

The twenty-four solar terms have skillfully combined astronomy, agriculture, weather and folklore, giving rise to a large number of seasonal cultures, which have become an important part of the traditional culture of the Chinese nation.

The "Twenty-four Solar Terms - a system of time knowledge and its practice formed by the Chinese through observing the annual movements of the sun" has been formally inscribed on the Representative List of the Intangible Cultural Heritage of Humanity

On Nov. 30, 2016, at the Ethiopian The 11th ordinary session of the Intergovernmental Committee for the Safeguarding of the Intangible Cultural Heritage of the United Nations Educational, Scientific and Cultural Organization (UNESCO), after deliberations, approved the inscription of the "Twenty-four Solar Terms - a system of knowledge of time and its practices developed by the Chinese through the observation of the sun's annual movements" on the Representative List of the Intangible Cultural Heritage of Humanity. UNESCO's Representative List of the Intangible Cultural Heritage of Humanity.

China's protection of the 24 solar terms has had a process: in 2006, the 24 solar terms were included in the first national list of representative items of intangible cultural heritage, and in 2011 and 2014, the Jiuhua Spring Festival, Banchun, Shiqian Spring Festival, Sanmen Winter Festival, Zhuang Frost Festival, Miao Catch the Autumn and Anren Catch the Fractions were included in the extended list of the heritage item.

The inscription of the 24 solar terms on the Representative List of the Intangible Cultural Heritage of Humanity reflects the importance the international community attaches to the safeguarding of intangible cultural heritage in the category of traditional knowledge and practices, and signifies the recognition of this outstanding cultural heritage and trust in China's commitment to safeguarding it. This requires China to mobilize all kinds of social forces, take more organized and planned protection measures, and actively promote the protection of the 24 solar terms.