Chinese calendar


The traditional Chinese calendar, is a lunisolar calendar which reckons years, months and days according to astronomical phenomena. In modern days, it is defined in China by GB/T 33661–2017, "Calculation and promulgation of the Chinese calendar", issued by the Standardisation Administration of China on 12 May 2017.
Although modern-day China uses the Gregorian calendar, the traditional Chinese calendar governs holidays—such as the Chinese New Year and Lantern Festival—in both China and in overseas Chinese communities. It also gives the traditional Chinese nomenclature of dates within a year, which people use for selecting auspicious days for weddings, funerals, moving, or starting a business. The evening state-run news program Xinwen Lianbo in the P.R.C. continues to announce the month and date in both the Gregorian and the traditional lunisolar calendar.
Like Chinese characters, variants of this calendar are used in different parts of the East Asian cultural sphere. Korea, Vietnam, and the Ryukyu Islands adopted the calendar, and it evolved into Korean, Vietnamese, and Ryukyuan calendars. The main difference from the traditional Chinese calendar is the use of different meridians, which leads to some astronomical events—and calendar events based on them—falling on different dates. The traditional Japanese calendar also derived from the Chinese calendar, but its official use in Japan was abolished in 1873 as part of reforms after the Meiji Restoration. Calendars in Mongolia and Tibet have absorbed elements of the traditional Chinese calendar, but are not direct descendants of it.
Days begin and end at midnight, and months begin on the day of the new moon. Years begin on the second new moon after the winter solstice. Solar terms govern the beginning and end of each month. A sexagenary cycle, consisting of stems and branches, is used as identification alongside each year, month, including intercalary months or leap months as needed. The length of a month is also annotated as either long or short.

History

Solar calendars

The traditional Chinese calendar was developed between 771 and 476 BC, during the Spring and Autumn period of the Eastern Zhou dynasty. Before the Zhou dynasty, solar calendars were used.
One version of the solar calendar is the five-elements calendar, which derives from the Wu Xing. A 365-day year was divided into five phases of 73 days, with each phase corresponding to a Day 1 Wu Xing element. A phase began with a governing-element day, followed by six 12-day weeks. Each phase consisted of two three-week months, making each year ten months long. Years began on a jiǎzǐ day, followed by a bǐngzǐ day and a 72-day fire phase; a wùzǐ day and a 72-day earth phase; a gēngzǐ day and a 72-day metal phase, and a rénzǐ day followed by a water phase. Other days were tracked using the Yellow River Map.
Another version is a four-quarters calendar. Weeks were ten days long, with one month consisting of three weeks. A year had 12 months, with a ten-day week intercalated in summer as needed to keep up with the tropical year. The 10 Heavenly Stems and 12 Earthly Branches were used to mark days.
A third version is the balanced calendar. A year was 365.25 days, and a month was 29.5 days. After every 16th month, a half-month was intercalated. According to oracle bone records, the Shang dynasty calendar was a balanced calendar with 12 to 14 months in a year; the month after the winter solstice was Zhēngyuè.

Lunisolar calendars

The first lunisolar calendar was the Zhou calendar, introduced under the Zhou dynasty. This calendar set the beginning of the year at the day of the new moon before the winter solstice.
Several competing lunisolar calendars were also introduced, especially by states fighting Zhou control during the Warring States period. The state of Lu issued its own Lu calendar. Jin issued the Xia calendar in AD 102, with a year beginning on the day of the new moon nearest the March equinox. Qin issued the Zhuanxu calendar, with a year beginning on the day of the new moon nearest the winter solstice. Song's Yin calendar began its year on the day of the new moon after the winter solstice.
These calendars are known as the six ancient calendars, or quarter-remainder calendars,, since all calculate a year as days long. Months begin on the day of the new moon, and a year has 12 or 13 months. Intercalary months are added to the end of the year. The Qiang and Dai calendars are modern versions of the Zhuanxu calendar, used by mountain peoples.

Qin and early Han dynasties

After Qin Shi Huang unified China under the Qin dynasty in 221 BC, the Qin calendar was introduced. It followed most of the rules governing the Zhuanxu calendar, but the month order was that of the Xia calendar; the year began with month 10 and ended with month 9, analogous to a Gregorian calendar beginning in October and ending in September. The intercalary month, known as the second Jiǔyuè, was placed at the end of the year. The Qin calendar was used into the Han dynasty.

Han-Ming dynasties and Taichu calendar

introduced reforms halfway through his reign. His Taichu Calendar defined a solar year as days, and the lunar month was days. This calendar introduced the 24 solar terms, dividing the year into 24 equal parts. Solar terms were paired, with the 12 combined periods known as climate terms.
The Taichu calendar established a framework for traditional calendars, with later calendars adding to the basic formula. The Dàmíng Calendar, created in the Liang dynasty by Zu Chongzhi, introduced the equinoxes. The use of a syzygy to determine the lunar month was first described in the Tang dynasty Wùyín Yuán Calendar. The Yuan dynasty Shòushí calendar used spherical trigonometry to find the length of the tropical year. The calendar had a 365.2425-day year, identical to the Gregorian calendar.

Modern calendars

Although the Chinese calendar lost its place as the country's official calendar at the beginning of the 20th century, its use has continued. Some calendars followed the last calendar of the Qing dynasty, published in 1908. This caused confusion about the date of the 1978 Mid-Autumn Festival, and those areas then switched to the UTC+8-based calendar.

Shíxiàn calendar

During the late Ming dynasty, Xu Guangqi and his colleagues worked out a new calendar based on Western astronomical arithmetic; however, the new calendar was not released before the end of the dynasty. In the early Qing dynasty, Johann Adam Schall von Bell submitted the calendar to the Shunzhi Emperor. The Qing government issued it as the Shíxiàn calendar.
In this calendar, the solar terms are 15° each along the ecliptic and it can be used as a solar calendar. However, the length of the climate term near perihelion is less than 30 days and there may be two mid-climate terms. The Shíxiàn calendar changed the mid-climate-term rule to "decides the month in sequence, except the intercalary month." The present traditional calendar follows the Shíxiàn calendar, except:
  1. The baseline is Chinese Standard Time, rather than Beijing local time.
  2. Astronomical data is used, rather than mathematical calculations.

    Proposals

To optimize the Chinese calendar, astronomers have proposed a number of changes. Gao Pingzi, a Chinese astronomer who co-founded the Purple Mountain Observatory, proposed that month numbers be calculated before the new moon and solar terms be rounded to the day. Since the intercalary month is determined by the first month without a mid-climate and the mid-climate time varies by time zone, countries which adopted the calendar but calculate with their own time could vary from the time in China.

Outlying areas

Calendars of ethnic groups in the mountains and plateaus of southwestern China and the grasslands of northern China are based on their phenology and algorithms of traditional calendars of different periods, particularly the Tang and pre-Qin dynasties.

Structure

Elements

Elements of the traditional Chinese calendar are:
The Chinese calendar is lunisolar, similar to the Hindu and Hebrew calendars.

Features

The movements of the sun, moon, Mercury, Venus, Mars, Jupiter and Saturn are the references for calendar calculations.
The Big Dipper is the celestial compass, and its handle's direction determines the season and month.
The stars are divided into Three Enclosures and 28 Mansions according to their location in the sky relative to Ursa Minor, at the centre. Each mansion is named with a character describing the shape of its principal asterism. The Three Enclosures are Purple Forbidden,, Supreme Palace, and Heavenly Market. The eastern mansions are,,,,,,. Southern mansions are,,,,,,. Western mansions are,,,,,,. Northern mansions are,,,,,,.
The moon moves through about one lunar mansion per day, so the 28 mansions were also used to count days. In the Tang dynasty, Yuan Tiangang matched the 28 mansions, seven luminaries and yearly animal signs to yield combinations such as "horn-wood-flood dragon".

Codes

Several coding systems are used to avoid ambiguity. The Heavenly Stems is a decimal system. The Earthly Branches, a duodecimal system, mark dual hours ) and climatic terms. The 12 characters progress from the first day with the same branch as the month of Zhēngyuè; first Mǎo day of Èryuè), and count the days of the month.
The stem-branches is a sexagesimal system. The Heavenly Stems and Earthly Branches make up 60 stem-branches. The stem-branches mark days and years. The five elements of the Wu Xing are assigned to each of the stems, branches and stem-branches.

Day

China has used the Western hour-minute-second system to divide the day since the Qing dynasty. Several era-dependent systems had been in use; systems using multiples of twelve and ten were popular, since they could be easily counted and aligned with the Heavenly Stems and Earthly Branches.

Week

As early as the Bronze-Age Xia dynasty, days were grouped into nine- or ten-day weeks known as xún. Months consisted of three xún. The first 10 days were the early xún, the middle 10 the mid xún, and the last nine days were the late xún. Japan adopted this pattern, with 10-day-weeks known as jun. In Korea, they were known as sun.
The structure of xún led to public holidays every five or ten days. During the Han dynasty, officials were legally required to rest every five days. The name of these breaks became huan.
Grouping days into sets of ten is still used today in referring to specific natural events. "Three Fu", a 29–30-day period which is the hottest of the year, reflects its three-xún length. After the winter solstice, nine sets of nine days were counted to calculate the end of winter.
The seven-day week was adopted from the Hellenistic system by the 4th century CE, although its source is unclear. It was again transmitted to China in the 8th century by Manichaeans via Kangju, and is the most-used system in modern China.

Month

Months are defined by the time between new moons, which averages approximately days. There is no specified length of any particular Chinese month, so the first month could have 29 days in some years and 30 days in other years.
A 12-month-year using this system has 354 days, which would drift significantly from the tropical year. To fix this, traditional Chinese years have a 13-month year approximately once every three years. The 13-month version has the same alternation of long and short months, but adds a 30-day leap month at the end of the year. Years with 12 months are called common years, and 13-month years are known as long years.
Although most of the above rules were used until the Tang dynasty, different eras used different systems to keep lunar and solar years aligned. The synodic month of the Taichu calendar was days long. The 7th-century, Tang-dynasty Wùyín Yuán Calendar was the first to determine month length by synodic month instead of the cycling method. Since then, month lengths have primarily been determined by observation and prediction.
The days of the month are always written with two characters and numbered beginning with 1. Days one to 10 are written with the day's numeral, preceded by the character Chū ; Chūyī is the first day of the month, and Chūshí the 10th. Days 11 to 20 are written as regular Chinese numerals; Shíwǔ is the 15th day of the month, and Èrshí the 20th. Days 21 to 29 are written with the character Niàn before the characters one through nine; Niànsān, for example, is the 23rd day of the month. Day 30 is written as the numeral Sānshí.
History books use days of the month numbered with the 60 stem-branches:
Because astronomical observation determines month length, dates on the calendar correspond to moon phases. The first day of each month is the new moon. On the seventh or eighth day of each month, the first-quarter moon is visible in the afternoon and early evening. In the 15th or 16th day of each month, the full moon is visible all night. On the 22nd or 23rd day of each month, the last-quarter moon is visible late at night and in the morning.
Since the beginning of the month is determined by the new moon occurs, other countries using this calendar use their own time standards to calculate it; this results in deviations. The first new moon in 1968 was at 16:29 UTC on 29 January. Since North Vietnam used to calculate their Vietnamese calendar and South Vietnam used to calculate theirs, North Vietnam began the Tết holiday at 29 January at 23:29 and South Vietnam began it on 30 January at 00:15. The time difference allowed asynchronous attacks in the Tet Offensive.

Names of months

Lunar months were originally named according to natural phenomena. Current naming conventions use numbers as the month names. Every month is also associated with one of the twelve Earthly Branches.
Month numberStarts on Gregorian datePhenological nameEarthly Branch nameModern name
1between 6 January – 5 February. square of Pegasus month
2between 5 February – 6 March
3between 6 March – 5 April
4between 5 April – 6 May
5between 6 May – 6 June
6between 6 June – 7 July
7between 7 July – 8 August
8between 8 August – 8 September
9between 8 September – 8 October
10between 8 October – 7 November
11between 7 November – 7 December;
12between 7 December – 6 January

Chinese lunar date conventions

Though the numbered month names are often used for the corresponding month number in the Gregorian calendar, it is important to realize that the numbered month names are not interchangeable with the Gregorian months when talking about lunar dates.
One may even find out the heavenly stem and earthly branch corresponding to a particular day in the month, and those corresponding to its month, and those to its year, to determine the Four Pillars of Destiny associated with it, for which the Tung Shing, also referred to as the Chinese Almanac of the year, or the Huangli, and containing the essential information concerning Chinese astrology, is the most convenient publication to consult. Days rotate through a sexagenary cycle marked by a coordination between heavenly stems and earthly branchs, hence the referral to the Four Pillars of Destiny as, "Bazi", or "Birth Time Eight Characters", with each pillar consisting of a character for its corresponding heavenly stem, and another for its earthly branch. Since Huangli days are sexagenaric, their order is quite independent from their numeric order in each month, and from their numeric order within a week. Therefore, it does require painstaking calculation for one to arrive at the Four Pillars of Destiny of a particular given date, which rarely outpace the convenience of simply consulting the Huangli by looking up its Gregorian date.

Solar term

The solar year, the time between winter solstices, is divided into 24 solar terms known as jié qì. Each term is a 15° portion of the ecliptic. These solar terms mark both Western and Chinese seasons as well as equinoxes, solstices, and other Chinese events. The even solar terms are considered the major terms, while the odd solar terms are deemed minor. The solar terms qīng míng on 5 April and dōng zhì on 22 December are both celebrated events in China.
NumberNameChinese markerEventDate
J1Lì chūn立春Beginning of spring4 February
Z1Yǔ shuĭ雨水Rain water19 February
J2Jīng zhé驚蟄；惊蛰Waking of insects6 March
Z2Chūn fēn春分March equinox21 March
J3Qīng míng清明Pure brightness5 April
Z3Gŭ yŭ谷雨Grain rain20 April
J4Lì xià立夏Beginning of summer6 May
Z4Xiǎo mǎn小滿；小满Grain full21 May
J5Máng zhòng芒種；芒种Grain in ear6 June
Z5Xià zhì夏至June solstice22 June
J6Xiǎo shǔ小暑Slight heat7 July
Z6Dà shǔ大暑Great heat23 July
J7Lì qiū立秋Beginning of autumn8 August
Z7Chǔ shǔ處暑；处署Limit of heat23 August
J8Bái lù白露White dew8 September
Z8Qiū fēn秋分September equinox23 September
J9Hán lù寒露Cold dew8 October
Z9Shuāng jiàng霜降Descent of frost24 October
J10Lì dōng立冬Beginning of winter8 November
Z10Xiăo xuě小雪Slight snow22 November
J11Dà xuě大雪Great snow7 December
Z11Dōng zhì冬至December solstice22 December
J12Xiăo hán小寒Slight cold6 January
Z12Dà hán大寒Great cold20 January

Solar year

The calendar solar year, known as the suì, begins at the December solstice and proceeds through the 24 solar terms. Due to the fact that the speed of the Sun's apparent motion in the elliptical is variable, the time between major solar terms is not fixed. This variation in time between major solar terms results in different solar year lengths. There are generally 11 or 12 complete months, plus two incomplete months around the winter solstice, in a solar year. The complete months are numbered from 0 to 10, and the incomplete months are considered the 11th month. If there are 12 complete months in the solar year, it is known as a leap solar year, or leap suì.
Due to the inconsistencies in the length of the solar year, different versions of the traditional calendar might have different average solar year lengths. For example, one solar year of the 1st century BC Tàichū calendar is days. A solar year of the 13th-century Shòushí calendar is days, identical to the Gregorian calendar. The additional.00766 day from the Tàichū calendar leads to a one-day shift every 130.5 years.
Pairs of solar terms are climate terms, or solar months. The first solar term is "pre-climate", and the second is "mid-climate".
The first month without a mid-climate is the leap, or intercalary, month. In other words, the first month that doesn't include a major solar term is the leap month. Leap months are numbered with rùn, the character for "intercalary", plus the name of the month they follow. In 2017, the intercalary month after month six was called Rùn Liùyuè, or "intercalary sixth month" and written as 6i or 6+. The next intercalary month will be called Rùn Sìyuè and written 4i or 4+.

Lunisolar year

The lunisolar year begins with the first spring month, Zhēngyuè, and ends with the last winter month, Làyuè. All other months are named for their number in the month order. If a leap month falls after month 11—as it will in 2033—the 11th month will be Shíèryuè, and the leap month will be Làyuè.
Years were traditionally numbered by the reign in ancient China, but this was abolished after the founding of the People's Republic of China in 1949. For example, the year from 8 February 2016 to 27 January 2017 was a Bǐngshēn year of.
During the Tang dynasty, the Earthly Branches were used to mark the months from December 761 to May 762. Over this period, the year began with the winter solstice.

Age reckoning

In China, a person's official age is based on the Gregorian calendar; for traditional use, age is based on the Chinese sui calendar. At birth, a child is considered the first year of lifetime using ordinal numeral ; after each Chinese New Year, one year is added to their traditional age. Because of the potential for confusion, infant ages are often given in months instead of years.
After the Gregorian calendar's introduction in China, the Chinese traditional age was referred to as the "nominal age" and the Gregorian age was known as the "real age".

Year-numbering systems

Eras
In ancient China, years were numbered from a new emperor's assumption of the throne or an existing emperor's announcement of a new era name. The first recorded reign title was Jiànyuán, from 140 BC; the last reign title was Xuāntǒng, from AD 1908. The era system was abolished in 1912, after which the current or Republican era was used.
Stem-branches
The 60 stem-branches have been used to mark the date since the Shang dynasty. Astrologers knew that the orbital period of Jupiter is about 4,332 days. Since 4332 is 12 × 361, Jupiter's orbital period was divided into 12 years of 361 days each. The stem-branches system solved the era system's problem of unequal reign lengths.
Continuous numbering
Nomenclature similar to that of the Christian era has occasionally been used:
No reference date is universally accepted. The most popular is the Gregorian calendar.
On 2 January 1912, Sun Yat-sen announced changes to the official calendar and era. 1 January was 14 Shíyīyuè 4609 Huángdì year, assuming a year 1 of 2698 BC. The change was adopted by many overseas Chinese communities, such as San Francisco's Chinatown.
During the 17th century, the Jesuits tried to determine the epochal year of the Han calendar. In his Sinicae historiae decas prima, Martino Martini dated the ascension of the Yellow Emperor to 2697 BC and began the Chinese calendar with the reign of Fuxi gave the same date for the Yellow Emperor. The Jesuits' dates provoked interest in Europe, where they were used for comparison with Biblical chronology. Modern Chinese chronology has generally accepted Martini's dates, except that it usually places the reign of the Yellow Emperor at 2698 BC and omits his predecessors Fuxi and Shennong as "too legendary to include".
Publications began using the estimated birth date of the Yellow Emperor as the first year of the Han calendar in 1903, with newspapers and magazines proposing different dates. The province of Jiangsu counted 1905 as the year 4396, and the newspaper Ming Pao reckoned 1905 as 4603. Liu Shipei created the Yellow Emperor Calendar, with year 0 as the birth of the emperor. There is no evidence that this calendar was used before the 20th century. Liu calculated that the 1900 international expedition sent by the Eight-Nation Alliance to suppress the Boxer Rebellion entered Beijing in the 4611th year of the Yellow Emperor.

Chinese New Year

The date of the Chinese New Year accords with the patterns of the solar calendar and hence is variable from year to year. However, there are two general rules that govern the date. Firstly, Chinese New Year transpires on the second new moon following the December solstice. If there is a leap month after the eleventh or twelfth month, then Chinese New Year falls on the third new moon after the December solstice. Alternatively, Chinese New Year will fall on the new moon that is closest to lì chūn, or the solar term that begins spring. However, this rule is not as reliable since it can be difficult to determine which new moon is the closest in the case of an early or late Chinese New Year.
It has been found that Chinese New Year moves back by either 10, 11, or 12 days in some years. If it falls before 21 January, then it moves forward in the next year by either 18, 19, or 20 days.

Phenology

The plum-rains season, the rainy season in late spring and early summer, begins on the first bǐng day after Mangzhong and ends on the first wèi day after Xiaoshu. The Three Fu are three periods of hot weather, counted from the first gēng day after the summer solstice. The first fu is 10 days long. The mid-fu is 10 or 20 days long. The last fu is 10 days from the first gēng day after the beginning of autumn. The Shujiu cold days are the 81 days after the winter solstice, and are considered the coldest days of the year. Each nine-day unit is known by its order in the set, followed by "nine".

Common Holidays Based on the Chinese (Lunar) Calendar

There are several traditional and religious holidays shared by communities throughout the world that use the Chinese calendar:

Holidays with the Same Day and Same Month

Lunar New Year is on the first day of the first month and was traditionally called the Yuan Dan or Zheng Ri. In Vietnam it is known as Tết Nguyên Đán and in Korea it is known as 설날. Traditionally it was the most important holiday of the year. It is an official holiday in China, Hong Kong, Macau, Taiwan, Vietnam, Korea, the Philippines, Malaysia, Singapore and Indonesia. It is also a public holiday in Thailand's Narathiwat, Pattani, Yala and Satun provinces and is an official public school holiday in New York City.
The Double Third Festival is on the third day of the third month and in Korea is known as 삼짇날.

The Dragon Boat Festival or the Duanwu Festival is on the fifth day of the fifth month and is an official holiday in China, Hong Kong, Macau and Taiwan. It is also celebrated in Vietnam where it is known as Tết Đoan Ngọ and in Korea where it is known as 단오 or 수릿날 .
The Qixi Festival is celebrated the evening of the seventh day of the seventh month. It is also celebrated in Vietnam where it is known as Thất tịch and in Korea where is known as 칠석.
The Double Ninth Festival is celebrated on the ninth day of the ninth month. It is also celebrated in Vietnam where it is known as Tết Trùng Cửuand in Korea where it is known as 중양절.

Full Moon Holidays (Holidays on the Fifteenth Day)

The Lantern Festival is celebrated on the fifteenth day of the first month and was traditionally called the Yuan Xiao or Shang Yuan Festival. In Vietnam it is known as Tết Thượng Nguyênand in Korea it is known as 대보름Daeboreum.
The Zhong Yuan Festival is celebrated on the fifteenth day of the seventh month. In Vietnam, it is celebrated as Tết Trung Nguyênor Lễ Vu Lan and in Korea it is known as 백중Baekjong or 망혼일Manghongil or 중원Jungwon.
The Mid-Autumn Festival is celebrated on the fifteenth day of the eighth month. In Vietnam, it is celebrated as Tết Trung Thuand in Korea it is known as 추석Chuseok.
The Xia Yuan Festival is celebrated on the fifteenth day of the tenth month. In Vietnam, it is celebrated as Tết Hạ Nguyên.

Celebrations of the Twelfth Month

The Laba Festival is on the eighth day of the twelfth month. It is the enlightenment day of Sakyamuni Buddha and is celebrated in Korea as 성도재일 and in Vietnam is known as Lễ Vía Phật Thích Ca Thành Đạo.
The Kitchen God Festival is celebrated on the twenty-third day of the twelfth month in northern regions of China or on the twenty-fourth day of the twelfth month in southern regions of China. In Vietnam it is known as Tết Táo Quân.
Chinese New Year's Eve is also known as the Chuxi Festival and is celebrated on the evening of the last day of the lunar calendar. It is celebrated where ever the lunar calendar is observed.

Celebrations of Solar-Term Holidays

The Qingming Festival is celebrated on the fifteenth day after the Spring Equinox. It is celebrated in Vietnam as Tết Thanh Minh.
The Dongzhi Festival or the Winter Solstice is celebrated as Lễ hội Đông Chíin Vietnam and as 동지in Korea.

Religious Holidays Based on the Lunar Calendar

East Asian Mahayana, Daoist and some Cao Dai holidays and/or vegetarian observances are based on the Lunar Calendar.

Celebrations in Japan

Many of the above holidays were celebrated in pre-Meiji Japan based on the lunar calendar but are now celebrated based on the Gregorian calendar.

Double Celebrations Due to Intercalary Months

In the case where there is a corresponding intercalary month, the holidays may be celebrated twice. For example, in the hypothetical situation where there is an additional intercalary seventh month, the Zhong Yuan Festival will be celebrated on the seventh month followed by another celebration on the intercalary seventh month.