| The Twenty-Four Solar Terms—— knowledge in China of time and practices developed through observation of the sun’s annual motion | |
|---|---|
| Country | China |
| Reference | 647 |
| Region | Asia and the Pacific |
| Inscription history | |
| Inscription | 2013 (11th session) |
| List | Representative |
 UNESCO Cultural Heritage | |
| (Twenty-four) solar terms | |||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Traditional Chinese | （二十四）節氣 | ||||||||||||||||||
| Simplified Chinese | （二十四）节气 | ||||||||||||||||||
| |||||||||||||||||||
| Term | Longitude | Dates |
|---|---|---|
| Lichun | 315° | 4–5 February |
| Yushui | 330° | 18–19 February |
| Jingzhe | 345° | 5–6 March |
| Chunfen | 0° | 20–21 March |
| Qingming | 15° | 4–5 April |
| Guyu | 30° | 20–21 April |
| Lixia | 45° | 5–6 May |
| Xiaoman | 60° | 21–22 May |
| Mangzhong | 75° | 5–6 June |
| Xiazhi | 90° | 21–22 June |
| Xiaoshu | 105° | 7–8 July |
| Dashu | 120° | 22–23 July |
| Liqiu | 135° | 7–8 August |
| Chushu | 150° | 23–24 August |
| Bailu | 165° | 7–8 September |
| Qiufen | 180° | 23–24 September |
| Hanlu | 195° | 8–9 October |
| Shuangjiang | 210° | 23–24 October |
| Lidong | 225° | 7–8 November |
| Xiaoxue | 240° | 22–23 November |
| Daxue | 255° | 7–8 December |
| Dongzhi | 270° | 21–22 December |
| Xiaohan | 285° | 5–6 January |
| Dahan | 300° | 20–21 January |
Asolar term (orjiéqì,simplified Chinese:节气;traditional Chinese:節氣) is any of twenty-four moments in traditionalChineselunisolar calendars that matches a particular astronomical event and signifies some natural phenomenon.[1] The points are spaced 15° apart along theecliptic[2] and are used by lunisolar calendars to stay synchronized with the seasons, which is crucial for agrarian societies. The solar terms are also used to calculateintercalary months;[3] which month is repeated depends on the position of the sun at the time.
According to theBook of Documents, the first determined term wasDongzhi (Winter Solstice) byDan, the Duke of Zhou, while he was trying to locate the geological center of theWestern Zhou dynasty, by measuring the length of the sun's shadow on an ancient type ofsundial calledtǔguī [ja] (土圭).[4] Then four terms of seasons were set, which were soon evolved as eight terms; not until the Taichu Calendar of 104 BC were all twenty-four solar terms officially included in the Chinese calendar.[5]
Because theSun's speed along the ecliptic varies depending on the Earth-Sun distance, the number of days that it takes the Sun to travel between each pair of solar terms varies slightly throughout the year, but it is always between 15 and 16 days. Each solar term is divided into threepentads [zh] (候;hòu), so there are 72 pentads in a year, consisting of five, rarely six, days. Most of them are named afterphenological (biological or botanical) phenomena corresponding to the pentad.
Solar terms originated inChina, then spread toKorea,Vietnam, andJapan, countries in theEast Asian cultural sphere. Although each term was named based on the seasonal changes of climate in theNorth China Plain, peoples living in the different climates still use it without changes.[6] This is exhibited by the fact thattraditional Chinese characters for most of the solar terms are identical.
On December 1, 2016, the solar terms were listed byUNESCO as anIntangible Cultural Heritage.[7]
The solar terms used to mark the midpoint of the month (marked with "Z", forChinese:中氣;pinyin:zhōngqì) are considered the major terms, while the solar terms used to mark the start of the month (marked with "J", forChinese:節氣;pinyin:jiéqì) are deemed minor. The year starts withLichun (J1) and ends withDahan (Z12).[8]
| Season | Chinese zodiac &Earthly Branch of Month | Sun's ecliptic longitude | Chinese name[9] | Korean name[10] | Vietnamese name | Japanese name | Ryukyuan (Okinawan) name | English name (Hong Kong Observatory)[11] | English name (CCTV)[12] | Gregorian Date[13] (± 1 day) | Reference for Month Intercalating | Corresponding Westernastrological sign |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Spring | Tiger (虎) Yín (寅) | 315° | 立春 lìchūn | 立春 (입춘/립춘) ipchun/ripchun | Lập xuân(立春) | 立春（りっしゅん） risshun | 立春（りっしゅん） risshun | Spring commences | Beginning of Spring | Feb 4 | 1st month initial | Aquarius |
| 330° | 雨水 yǔshuǐ[14] | 雨水 (우수) usu | Vũ thủy(雨水) | 雨水（うすい） usui | 雨水（うしー） ushii | Rain water | Rain Water | Feb 19 | 1st month midpoint | Pisces | ||
| Rabbit (兔) Mǎo (卯) | 345° | 驚蟄 (惊蛰) jīngzhé[15] | 驚蟄 (경칩) gyeongchip | Kinh trập(驚蟄) | 啓蟄（けいちつ） keichitsu | 驚く（うどぅるく） | Insects waken | Awakening of Insects | Mar 6 | 2nd month initial | ||
| 0° | 春分 chūnfēn | 春分 (춘분) chunbun | Xuân phân(春分) | 春分（しゅんぶん） shunbun | 春分（すんぶん） sunbun | Vernal equinox | Spring Equinox | Mar 21 | 2nd month midpoint | Aries | ||
| Dragon (龍) Chén (辰) | 15° | 清明 qīngmíng[16] | 淸明 (청명) cheongmyeong | Thanh minh(清明) | 清明（せいめい） seimei | 清明（しーみー） shiimii | Bright and clear | Pure Brightness | Apr 5 | 3rd month initial | ||
| 30° | 穀雨 (谷雨) gǔyǔ[17] | 穀雨 (곡우) gogu | Cốc vũ(穀雨) | 穀雨（こくう） kokuu | 穀雨（くくー） kukuu | Corn rain | Grain Rain | Apr 20 | 3rd month midpoint | Taurus | ||
| Summer | Snake (蛇) Sì (巳) | 45° | 立夏 lìxià | 立夏 (입하/립하) ipha/ripha | Lập hạ(立夏) | 立夏（りっか） rikka | 立夏（りっかー） rikkaa | Summer commences | Beginning of Summer | May 6 | 4th month initial | |
| 60° | 小滿 (小满) xiǎomǎn | 小滿 (소만) soman | Tiểu mãn(小滿) | 小満（しょうまん） shōman | 小満（すーまん） suuman | Corn forms | Grain Buds | May 21 | 4th month midpoint | Gemini | ||
| Horse (馬) Wǔ (午) | 75° | 芒種 (芒种) mángzhòng | 芒種 (망종) mangjong | Mang chủng(芒種) | 芒種（ぼうしゅ） bōshu | 芒種（ぼーすー） boosuu | Corn on ear | Grain in Ear | Jun 6 | 5th month initial | ||
| 90° | 夏至 xiàzhì | 夏至 (하지) haji | Hạ chí(夏至) | 夏至（げし） geshi | 夏至（かーちー） kaachii | Summer solstice | Summer Solstice | Jun 21 | 5th month midpoint | Cancer | ||
| Goat (羊) Wèi (未) | 105° | 小暑 xiǎoshǔ | 小暑 (소서) soseo | Tiểu thử(小暑) | 小暑（しょうしょ） shōsho | 小暑（くーあちさ） kuu'achisa | Moderate heat | Minor Heat | Jul 7 | 6th month initial | ||
| 120° | 大暑 dàshǔ | 大暑 (대서) daeseo | Đại thử(大暑) | 大暑（たいしょ） taisho | 大暑（うーあちさ） uu'achisa | Great heat | Major Heat | Jul 23 | 6th month midpoint | Leo | ||
| Autumn | Monkey (猴) Shēn (申) | 135° | 立秋 lìqiū | 立秋 (입추/립추) ipchu/ripchu | Lập thu(立秋) | 立秋（りっしゅう） risshū | 立秋（りっすー） rissuu | Autumn commences | Beginning of Autumn | Aug 8 | 7th month initial | |
| 150° | 處暑 (处暑) chǔshǔ | 處暑 (처서) cheoseo | Xử thử(處暑) | 処暑（しょしょ） shosho | 処暑（とぅくるあちさ） tukuru'achisa | End of heat | End of Heat | Aug 23 | 7th month midpoint | Virgo | ||
| Rooster (雞) Yǒu (酉) | 165° | 白露 báilù | 白露 (백로) baengno | Bạch lộ(白露) | 白露（はくろ） hakuro | 白露（ふぁくるー） fakuruu | White dew | White Dew | Sep 8 | 8th month initial | ||
| 180° | 秋分 qiūfēn | 秋分 (추분) chubun | Thu phân(秋分) | 秋分（しゅうぶん） shūbun | 秋分（すーぶん） suubun | Autumnal equinox | Autumn Equinox | Sep 23 | 8th month midpoint | Libra | ||
| Dog (狗) Xū (戌) | 195° | 寒露 hánlù | 寒露 (한로) hallo | Hàn lộ(寒露) | 寒露（かんろ） kanro | 寒露（かんるー） kanruu | Cold dew | Cold Dew | Oct 8 | 9th month initial | ||
| 210° | 霜降 shuāngjiàng | 霜降 (상강) sanggang | Sương giáng(霜降) | 霜降（そうこう） sōkō | 霜降（しむくだり） shimukudari | Frost | Frost's Descent | Oct 23 | 9th month midpoint | Scorpio | ||
| Winter | Pig (豬) Hài (亥) | 225° | 立冬 lìdōng | 立冬 (입동/립동) ipdong/ripdong | Lập đông(立冬) | 立冬（りっとう） rittō | 立冬（りっとぅー） rittuu | Winter commences | Beginning of Winter | Nov 7 | 10th month initial | |
| 240° | 小雪 xiǎoxuě | 小雪 (소설) soseol | Tiểu tuyết(小雪) | 小雪（しょうせつ） shōsetsu | 小雪（くーゆち） kuuyuchi | Light snow | Minor Snow | Nov 22 | 10th month midpoint | Sagittarius | ||
| Rat (鼠) Zǐ (子) | 255° | 大雪 dàxuě | 大雪 (대설) daeseol | Đại tuyết(大雪) | 大雪（たいせつ） taisetsu | 大雪（うーゆち） uuyuchi | Heavy snow | Major Snow | Dec 7 | 11th month initial | ||
| 270° | 冬至 dōngzhì | 冬至 (동지) dongji | Đông chí(冬至) | 冬至（とうじ） tōji | 冬至（とぅんじー） tunjii | Winter solstice | Winter Solstice | Dec 22 | 11th month midpoint | Capricorn | ||
| Ox (牛) Chǒu (丑) | 285° | 小寒 xiǎohán | 小寒 (소한) sohan | Tiểu hàn(小寒) | 小寒（しょうかん） shōkan | 小寒（すーかん） suukan | Moderate cold | Minor Cold | Jan 6 | 12th month initial | ||
| 300° | 大寒 dàhán | 大寒 (대한) daehan | Đại hàn(大寒) | 大寒（だいかん） daikan | 大寒（でーかん） deekan | Severe cold | Major Cold | Jan 20 | 12th month midpoint | Aquarius |
The "Song of Solar Terms" (simplified Chinese:节气歌;traditional Chinese:節氣歌;pinyin:jiéqìgē) is used to ease the memorization ofjieqi:
春雨驚春清穀天 |
春雨惊春清谷天 |
chūn yǔ jīng chūn qīng gǔ tiān, |
The first four lines provides a concise version of the names of the 24jieqi. The last four lines provide some rules of thumb about the Gregorian dates ofjieqi, namely:
The modern definition using ecliptic longitudes, introduced by theShixian calendar, is known as定气法 (dìng qì fǎ,'steady term method'). Under this method, the determination of solar terms is similar to the astronomical determination of the special cases ofequinox andsolstice dates, with different ecliptic longitudes to solve for. One can start with an approximation and then perform a correction using the anomalies andmean motion of the sun.[18] TheJPL Horizons On-Line Ephemeris System may be used to query for exact times of solar terms.
The older method is known as平气法 (píng qì fǎ,'equal term method') and simply divides thetropical year into 24 equal parts.
In Japan, the termSetsubun (節分) originally referred to the eves ofRisshun (立春, 315°, the beginning of Spring),Rikka (立夏, 45°, the beginning of Summer),Risshū (立秋, 135°, the beginning of Autumn), andRittō (立冬, 225°, the beginning of Winter), but currently mostly refers to the day beforeRisshun. The name of each solar term also refers to the period of time between that day and the next solar term, or 1/24th of a year.