Jieqi (or solar terms) are days marking one of the 24 time zones of the solar year in traditional Chinese calendar. Jieqi was used to indicate the alternation of seasons and climate changes in ancient China. It is a unique component and creative invention of Chinese traditional calendar.
Originated in the Yellow River reaches, Jieqi reflected our ancestors' knowledge about climate changes during their farming activities. Over the years, Jieqi has played an important role in China's agricultural and animal husbandry production. In reality, the actual solstice/equinox dates vary by plus or minus one day, hence the variation between such reference lists as Cohen Introduction 412 and the back of the Mathews dictionary (used here). Readers located in the North Temperate Zone should find the defining events generally familiar; the list was apparently devised for approximately 35' N latitude.
The 24 solar divisions begin with the "Start of Spring", which is followed in turn by "Rain Water", when preparations for planting are made; "Excited Insects", a time of spring thunder and the stirring of new life; the Spring Equinox; "Clear and Bright", marked by the howling of southeasterly winds; and "Grain Rains", reminding the farmers that the seasonal downpours are beginning. The summer divisions begin with "Start of Summer"; "Grain Fills", when the grain swells on the stalks; "Grain in Ear", marking the time of harvest; the Summer Solstice; and "Slight Heat" and "Great Heat", when the warmth of summer becomes increasingly more oppressive.
The summer divisions are followed in turn by the "Start of Autumn", the day on which the temperature begins to cool; "White Dew", when the moisture congeals to frost; the Autumnal Equinox, the true start of the fall season; and followed with "Cold Dew" and " Frost Descends", the weather turns cold as winter nears. The "Start of Winter" is followed by "Light Snow" and "Heavy Snow", which mark the beginning of deep winter. The next division in the year, Winter Solstice, is a day of deep significance, celebrated in Taiwan by eating a kind of sweet dumpling soup called Tangyuan to fortify the body in preparation for the biting frost of "Little Cold" and "Severe Cold", the final two divisions of the cycle before beginning the new year.
The Twenty-four Solar Terms
- 1st solar term: the Beginning of Spring
- 2nd solar term: Rain Water
- 3rd solar term: the Waking of Insects
- 4th solar term: the Spring Equinox
- 5th solar term: Pure Brightness
- 6th solar term: Grain Rain
- 7th solar term: the Beginning of Summer
- 8th solar term: Grain Full
- 9th solar term: Grain in Ear
- 10th solar term: the Summer Solstice
- 11th solar term: Slight Heat
- 12th solar term: Great Heat
- 13th solar term: the Beginning of Autumn
- 14th solar term: the Limit of Heat
- 15th solar term: White Dew
- 16th solar term: the Autumnal Equinox
- 17th solar term: Cold Dew
- 18th solar term: Frost's descent
- 19th solar term: the Beginning of Winter
- 20th solar term: Slight Snow
- 21st solar term: Great Snow
- 22nd solar term: the Winter Solstice
- 23rd solar term: Slight Cold
- 24th solar term: Great Cold