二十四节气 The Twenty-four Solar Terms

古代一组节令的总称，即自立春至大寒共二十四个节气，以表征一年中天文、季节、气候与农业生产的关系。它是中国古代独特的创造。作为一部完整的农业气候历，在指导中国农业生产上发挥了较大作用，沿用至今。

二十四节气的形成和发展与中国农业生产的发展紧密相连。农业发展初期，由于播种和收获等农事活动的需要，开始探索农业生产的季节规律，出现了春种、夏长、秋收、冬藏的概念。春秋战国以后随着铁制农具的出现,农业生产对季节性的要求更高了,就逐渐形成了节气的概念。春秋时已用土圭测日影定节气。最初只有夏至、冬至，随后逐渐增加了春分、秋分及立春、立夏、立秋、立冬。

二十四节气在天文学上是以视太阳在黄道上的位置来确定的。以黄经0°为春分,以下每15°为一节气,周天为360°而成二十四节气。二十四节气后传入朝鲜、日本等邻国。日本在江户时代(1603～1867)开始采用，并传至今日。

The Twenty-four Solar Terms

In the ancient times, there was a general name for a group of seasons, i.e. the Twenty-four Solar Terms from the Beginning of Spring to Great Cold. It shows the relationship between universe, season, climate and agriculture, which is unique creation by Chinese ancestors. To date, it has functioned as a complete set of weather calendar to guide the agricultural production in China.

The Twenty-four Solar Terms come to being and develop in close relationship with Chinese agricultural production. At the initial stage of agricultural development, people began to explore the seasonal rule in the agricultural production to meet the needs in seeding, harvesting and other activities. Gradually, there formed the concept of "Seed in Spring, Grow in Summer, Harvest in Autumn and Store in Winter". During the Spring and Autumn Period (770-476 BC), the agricultural production was highly subject to the seasonal changes with the invention of iron tools, thus forming the concept of Solar Term. At that time, the method of tugui was used to measure the shadow of the sun for determining the solar terms. Initially, there were only the Summer Solstice and the Winter Solstice. Later added were the Spring Equinox, the Autumnal Equinox, the Beginning of Spring, the Beginning of Summer, the Beginning of Autumn and the Beginning of Winter.

Astronomically, the Twenty-four Solar Terms are defined according to the position of the sun on the ecliptic. 0 degree of celestial longitude is the Spring Equinox and the every solar term matches the passage 15 degrees. As a result, there come Twenty-four Solar Terms as it passes by 360 degrees. Later, the Twenty-four Solar Terms were introduced into North Korea, Japan and other neighboring countries. During the Edo Period (1603-1867), Japan began to adopt the Twenty-four Solar Terms, which have been used till now.

立春 the Beginning of Spring (1st solar term February 3-5)
雨水 Rain Water (2nd solar term February 18-20)
惊蛰 the Waking of Insects (3rd solar term March 5-7)
春分 the Spring Equinox (4th solar term March 20-22)
清明 Pure Brightness (5th solar term April 4-6)
谷雨 Grain Rain (6th solar term April 19-21)
立夏 the Beginning of Summer (7th solar term May 5-7)
小满 Grain Full (8th solar term May 20-22)
芒种 Grain in Ear (9th solar term June 5-7)
夏至 the Summer Solstice (10th solar term June 21-22)
小暑 Slight Heat (11th solar term July 6-8)
大暑 Great Heat (12th solar term July 22-24)
立秋 the Beginning of Autumn (13th solar term August 7-9)
处暑 the Limit of Heat (14th solar term August 22-24)
白露 White Dew (15th solar term September 7-9)
秋分 the Autumnal Equinox (16th solar term September 22-24)
寒露 Cold Dew (17th solar term October 8-9)
霜降 Frost's Descent (18th solar term October 23-24)
立冬 the Beginning of Winter (19th solar term November 7-8)
小雪 Slight Snow (20th solar term November 22-23)
大雪 Great Snow (21st solar term December 6-8)
冬至 the Winter Solstice (22nd solar term December 21-23)
小寒 Slight Cold (23rd solar term January 5-7)
大寒 Great Cold (24th solar term January 20-21)

(China.org.cn April 7, 2011)