Chronometry: The Measurments of Time, Seasons and Year by the Chinese

 As the current Chinese Zodiac Year of The Rabbit, the year I was born comes to a close exactly 2 weeks from now to give way to the Year of the Dragon on 10 February 2024 here is a brief history of the Chinese Calendar according to some information from Wikipedia with some corrections, deletions, editing and updating.

I shall write a better and more detailed technical version later. Briefly, we shall start with the current symbolic zodiac of the twelve animals. 

The Chinese zodiac of 12 animals, each representing a new lunar year in cycles is a traditional classification scheme based on the Chinese calendar.  In traditional Chinese culture, the Chinese zodiac is very important and exists as a reflection of Chinese beliefs and their culture. The Chinese belief system held that one’s personality is related to the attributes of their zodiac animal.  Although its origin is from China, the zodiac and its variations remain popular in many East Asian and Southeast Asian countries where the Chinese have migrated.

Identifying this scheme using the generic term "zodiac" replicates several superficial similarities to the Western zodiac: both have time cycles divided into twelve parts, each mark at least the majority of those parts with names of animals, and each is widely associated with a culture of ascribing a person's personality or events in their life to the supposed influence of the person's particular relationship to the cycle.

Surprisingly, the 12 Chinese zodiac animals in a cycle are not only used to represent years in China, but also believed to influence people’s personalities, career, compatibility, marriage, and fortune.

For the starting date of a zodiac year, there are two schools of thought in Chinese astrology: Chinese New Year or the Start of Spring.

The animals of the Chinese zodiac are not associated with constellations spanned by the ecliptic plane in astronomy. The Chinese twelve-part cycle corresponds to years, rather than months. The Chinese zodiac is calculated from the lunar calendar, which is based on astronomical observations of the longitude of the sun and the circularity of the moon.

Having briefly said this, the Chinese calendar is far more ancient and historical than the zodiac calendar.

Furthermore, the zodiac calendar does not tell us a single bit how time in days, months and years are measured. It just symbolizes the cycles of animals in each Chinese lunar year. So, we need to be more technical than that to examine how the various types of calendars were constructed. 

The Chronmetry of Chinese Calendars:

As far as I know, there are many types and subtypes of the Chinese calendars used for time measurements which over a millennium plus history has shaped many disparities, currently mainly associated with the 21st century nation state of the People's Republic of China. The topic of the Chinese calendar embraces various traditional types of the Chinese calendar, of which particularly obvious are, identifying years, months, and days according to astronomical phenomena and calculations, with usually an especial effort to correlate the solar and lunar cycles experienced on earth—but which are known to mathematically require some degree of approximation. Typical characteristics of early calendars incorporate the use of the sexagenary cycle-based ganzhi system's replicating cycles of Heavenly Stems and Earthly Branches. The logic of the various permutations of the Chinese calendar was based on technical mathematics and astronomy, the philosophical considerations, and the political, and the resulting disparities between different calendars is significant and notable. Numerous similar calendar systems are also known from various regions or ethnic groups of Central Asia, South Asia, and other areas. Indeed, the Chinese calendar has influenced and been influenced by most parts of the world these days. One predominantly popular feature is the Chinese zodiac as already briefly metioned. The Chinese calendar and horology include many multifaceted methods of computing years, eras, months, days, and hours (with modern horology even splitting the seconds).

Epochs are one of the important landscapes of calendar systems. An epoch is a particular point in time at which a calendar system may use as its initial time reference, allowing for the consecutive numbering of years from a chosen starting year, date, or time. In the Chinese calendar system, examples include the inauguration of Huangdi or the birth of Confucius. Likewise, many dynasties had their own dating systems, which could include regnal eras based on the inauguration of a dynasty, the enthronement of a particular monarch, or eras arbitrarily designated due to political or other considerations, such as a desire for a change the luck. Era names are useful for determining dates on artifacts such as ceramics, which were often traditionally dated by an era name during the production process.

Variations of the lunisolar calendar are a predominantly prominent feature of the Chinese calendar system. The topic of the Chinese calendar includes various traditional types of the Chinese calendar, of which particularly prominent are, identifying years, months, and days according to astronomical phenomena and calculations, with generally an especial effort to correlate the solar and lunar cycles experienced on earth—but which are recognized to mathematically require some degree of approximation. One of the major features of some traditional calendrical systems in China (and elsewhere) was the idea of the sexagenary cycle. The Chinese lunisolar calendar has had several significant variations over the course of time and history, and despite the name also deliberates various other astronomical phenomena besides the cycles of the sun and the moon, such as the planets and the constellations (or mansions) of asterisms along the ecliptic. Many Chinese holidays ancient and modern have been determined by a lunisolar calendar or considerations of the lunisolar calendar, now generally combined with more modern calendar considerations.

Solar and agricultural calendars have a long history in China. Purely lunar calendar systems were known in China, however they tended to be of limited utility, and were not widely accepted by farmers who for agricultural purposes needed to focus on predictability of seasons for planting and harvesting purposes and to thereby produce a useful agricultural calendar. For farming purposes and keeping track of the seasons Chinese solar calendars were particularly useful. The publication of multipurpose and agricultural almanacs has been a longstanding tradition in China.

The horology of the Chinese calendar also embraces variations of the modern Chinese calendar, influenced by the Gregorian calendar, which is a calendar system which was initially adopted in parts of Europe in 1582. Variations include methodologies of the People's Republic of China and Taiwan.

No reference date is universally accepted. The most popular is the Gregorian calendar (公曆; 公历; gōnglì; 'common calendar').

During the 17th century, the Jesuit missionaries tried to determine the epochal year of the Chinese calendar. In his Sinicae historiae decas prima (published in Munich in 1658), Martino Martini (1614–1661) dated the Yellow Emperor's ascension at 2697 BCE and began the Chinese calendar with the reign of Fuxi (which, according to Martini, began in 2952 BCE). Philippe Couplet's 1686 Chronological table of Chinese monarchs (Tabula chronologica monarchiae sinicae) 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 BCE 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. Jiangsu province counted 1905 as the year 4396 (using a year 1 of 2491 BCE, and implying that 2024 CE is 4515), and the newspaper Ming Pao (明報) reckoned 1905 as 4603 (using a year 1 of 2698 BCE and implying that 2024 CE is 4722). Liu Shipei (劉師培, 1884–1919) created the Yellow Emperor Calendar (黃帝紀元, 黃帝曆 or 軒轅紀年), with year 1 as the birth of the emperor (which he determined as 2711 BCE, implying that 2024 CE is 4735). 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.

Taoists later adopted Yellow Emperor Calendar and named it Tao Calendar (道曆).

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 BCE, making 2024 CE year 4722. Many overseas Chinese communities like San Francisco's Chinatown adopted the change.

The modern Chinese standard calendar uses the epoch of the Gregorian calendar, which is on January 1 of the year 1 CE.

Lunisolar calendar:

Lunisolar calendars involve correlations of the cycles of the sun (solar) and the moon (lunar).

Solar and agricultural:

A solar calendar keeps track of the seasons as the earth and the sun move in the solar system relatively to each other. A purely solar calendar may be suitable in planning times for agricultural activities such as planting and harvesting. Solar calendars tend to use astronomically observable points of reference such as equinoxes and solstices, events which may be approximately predicted using fundamental methods of observation and basic mathematical analysis.

Modern Chinese calendar and horology:

The topic of the Chinese calendar also embraces variations of the modern Chinese calendar, influenced by the Gregorian calendar. Variations include methodologies of the People's Republic of China and Taiwan.

Modern calendars:

In China, the modern calendar is defined by the Chinese national standard GB/T 33661–2017, "Calculation and Promulgation of the Chinese Calendar", issued by the Standardization Administration of China on May 12, 2017.

 Influence of Gregorian calendar:

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 overseas Chinese communities. It also provides the traditional Chinese nomenclature of dates within a year which people use to select auspicious days for weddings, funerals, moving or starting a business. The evening state-run news program Xinwen Lianbo in the People's Republic of China continues to announce the months and dates in both the Gregorian and the traditional lunisolar calendar.

History:

The Chinese calendar system has a long history, which has traditionally been linked with specific dynastic periods. Various separate calendar types have been developed with different names. In terms of historical development, some of the calendar variations are associated with dynastic changes along a spectrum beginning with a prehistorical / mythological time to and through well attested historical dynastic periods. Many individuals have been associated with the development of the Chinese calendar, including researchers into underlying astronomy; and, furthermore, the development of instruments of observation are historically important. Influences from India, Islam, and Jesuits also became significant.

Phenology:

Early calendar systems often were closely tied to natural phenomena. Phenology is the study of periodic events in biological life cycles and how these are influenced by seasonal and interannual variations in climate, as well as habitat factors (such as elevation). The plum-rains season (梅雨), the rainy season in late spring and early summer, begins on the first bǐng day after Mangzhong (芒種) and ends on the first wèi day after Xiaoshu (小暑). The Three Fu (三伏; sānfú) are three periods of hot weather, counted from the first gēng day after the summer solstice. The first fu (初伏; chūfú) is 10 days long. The mid-fu (中伏; zhōngfú) is 10 or 20 days long. The last fu (末伏; mòfú) is 10 days from the first gēng day after the beginning of autumn.The Shujiu cold days (數九; shǔjǐu; 'counting to nine') are the 81 days after the winter solstice (divided into nine sets of nine days), and are considered the coldest days of the year. Each nine-day unit is known by its order in the set, followed by "nine" (九). In traditional Chinese culture, "nine" represents the infinity, which is also the number of "Yang". According to one belief nine times accumulation of "Yang" gradually reduces the "Yin", and finally the weather becomes warm.

Names of months

Lunar months were originally named according to natural phenomena. Contemporary naming conventions use numbers as the month names. Every month is also associated with one of the twelve Earthly Branches.

• Gregorian dates are approximate and should be used with caution. Many years have intercalary months.

Chinese astronomy:

 The Chinese calendar has been an enlargement involving much observation and calculation of the apparent movements of the Sun, Moon, planets, and stars, as observed from Earth.

Chinese astronomers:

Many Chinese astronomers have contributed to the development of the Chinese calendar. Many were of the scholarly or shi class (Chinese: 士; pinyin: shì), including writers of history, such as Sima Qian.

Distinguished Chinese astronomers who have contributed to the development of the calendar include Gan De, Shi Shen, and Zu Chongzhi

Technology:

Early technological developments assisting in calendar development include the development of the gnomon. Later technological developments useful to the calendar system include naming, numbering, and mapping of the sky, the development of analog computational devices such as the armillary sphere and the water clock, and the establishment of observatories.

Ancient six calendars:

From the Warring States period (ending in 221 BCE), six especially significant calendar systems are known to have begun to be developed. Later, during their future course in history, the modern names for the ancient six calendars were also developed, and can be translated into English as Huangdi, Yin, Zhou, Xia, Zhuanxu, and Lu.

Calendar variations:

There are various Chinese terms for calendar variations including:

• Nongli Calendar (traditional Chinese: 農曆; simplified Chinese: 农历; pinyin: nónglì; lit. 'agricultural calendar')
• Jiuli Calendar (traditional Chinese: 舊曆; simplified Chinese: 旧历; pinyin: jiùlì; Jyutping: Gau6 Lik6; lit.'former calendar')
• Laoli Calendar (traditional Chinese: 老曆; simplified Chinese: 老历; pinyin: lǎolì; lit. 'old calendar')
• Zhongli Calendar (traditional Chinese: 中曆; simplified Chinese: 中历; pinyin: zhōnglì; Jyutping: zung1 lik6; lit. 'Chinese calendar')
• Huali Calendar (traditional Chinese: 華曆; simplified Chinese: 华历; pinyin: huálì; Jyutping: waa4 lik6; lit. 'Chinese calendar')2017 Chinese calendar

Solar calendars:

Five-phase and four-quarter calendars

The traditional Chinese calendar was developed between 771 and 476 BCE, during the Spring and Autumn period of the Eastern Zhou dynasty. Solar calendars were used before the Zhou dynasty period, along with the basic sexagenary system.

Five-elements calendar:

One version of the solar calendar is the five-elements calendar (五行曆; 五行历), 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 (行御), 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 (甲子) day (and a 72-day wood phase), followed by a bǐngzǐ day (丙子) and a 72-day fire phase; a wùzǐ (戊子) day and a 72-day earth phase; a gēngzǐ (庚子) day and a 72-day metal phase, and a rénzǐ day (壬子) followed by a water phase. Other days were tracked using the Yellow River Map (He Tu).

Four-quarters calendar:

Another version is a four-quarters calendar (四時八節曆; 四时八节历; 'four sections', 'eight seasons calendar', or 四分曆; 四分历). The 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.

Well-adjusted calendar:

A third version is the balanced calendar (調曆; 调历). 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 (c. 1600 – c. 1046 BCE) was a balanced calendar with 12 to 14 months in a year; the month after the winter solstice was Zhēngyuè.

Lunisolar calendars by dynasty: Six ancient calendars:

Modern historical knowledge and records are limited for the earlier calendars. These calendars are known as the six ancient calendars (古六曆; 古六历), or quarter-remainder calendars, (四分曆; 四分历; sìfēnlì), since all calculate a year as 365+¹⁄₄ days long. Months begin on the day of the new moon, and a year has 12 or 13 months. Intercalary months (a 13th month) are added to the end of the year. The Qiang and Dai calendars are modern versions of the Zhuanxu calendar, used by mountain peoples.

Zhou dynasty:

The first lunisolar calendar was the Zhou calendar (周曆; 周历), introduced under the Zhou dynasty (1046 BC – 256 BCE). This calendar sets the beginning of the year at the day of the new moon before the winter solstice.

Competing Warring states calendars:

Several competing lunisolar calendars were also introduced as Zhou devolved into the Warring States, especially by states fighting Zhou control during the Warring States period (perhaps 475-221 BCE). The state of Lu issued its own Lu calendar (魯曆; ). Jin issued the Xia calendar (夏曆; 夏历) with a year beginning on the day of the new moon nearest the March equinox. Qin issued the Zhuanxu calendar (顓頊曆; 颛顼历), with a year beginning on the day of the new moon nearest the winter solstice. Song's Yin calendar (殷曆; 殷历) began its year on the day of the new moon after the winter solstice.

Qin and early Han dynasties:

After Qin Shi Huang unified China under the Qin dynasty in 221 BCE, the Qin calendar (秦曆; 秦历) 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 (後九月; 后九月; 'later Jiǔyuè'), was placed at the end of the year. The Qin calendar was used going into the Han dynasty.

Han dynasty Tàichū calendar:

Emperor Wu of Han r. 141 – 87 BCE introduced reforms in the seventh of the eleven named eras of his reign, Tàichū (Chinese: 太初; pinyin: Tàichū; lit. 'Grand Beginning'), 104 BC – 101 BCE. His Tàichū Calendar (太初曆; 太初历; 'grand beginning calendar') defined a solar year as 365+³⁸⁵⁄₁₅₃₉ days (365; 06:00:14.035), and the lunar month had 29+⁴³⁄₈₁ days (29;12:44:44.444). Since the 19 years cycle used for the 7 additional months was taken as an exact one, and not as an approximation.

This calendar introduced the 24 solar terms, dividing the year into 24 equal parts of 15° each. Solar terms were paired, with the 12 combined periods known as climate terms. The first solar term of the period was known as a pre-climate (节气), and the second was a mid-climate (中气). Months were named for the mid-climate to which they were closest, and a month without a mid-climate was an intercalary month.

The Taichu calendar established a framework for traditional calendars, with later calendars adding to the basic formula.

Northern and Southern Dynasties Dàmíng calendar:

The Dàmíng Calendar (大明曆; 大明历; 'brightest calendar'), created in the Northern and Southern Dynasties by Zu Chongzhi (429–500 AD), introduced the equinoxes.

Tang dynasty Wùyín Yuán calendar:

The use of syzygy in astronomy to determine the lunar month was first described in the Tang dynasty Wùyín Yuán Calendar (戊寅元曆; 戊寅元历; 'earth tiger epoch calendar').

Yuan dynasty Shòushí calendar:

The Yuan dynasty Shòushí calendar (授時曆; 授时历; 'season granting 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.

Although the Chinese calendar lost its place as the country's official calendar at the beginning of the 20th century, its use has continued. The Republic of China Calendar published by the Beiyang government of the Republic of China still listed the dates of the Chinese calendar in addition to the Gregorian calendar. In 1929, the Nationalist government tried to ban the traditional Chinese calendar. The Kuómín Calendar published by the government no longer listed the dates of the Chinese calendar. However, Chinese people were used to the traditional calendar and many traditional customs were based on the Chinese calendar. The ban failed and was lifted in 1934. The latest Chinese calendar was "New Edition of Wànniánlì, revised edition", edited by Beijing Purple Mountain Observatory, People's Republic of China.

Shíxiàn calendar:

From 1645 to 1913 the Shíxiàn or Chongzhen was developed. During the late Ming dynasty, the Chinese Emperor appointed Xu Guangqi in 1629 to be the leader of the ShiXian calendar reform. Supported by Jesuits, he translated Western astronomical works and introduced new concepts, such as those of Nicolaus Copernicus, Johannes Kepler, Galileo Galilei, and Tycho Brahe; 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 which was edited by the lead of Xu Guangqi to the Shunzhi Emperor. The Qing government issued it as the Shíxiàn (seasonal) calendar. In this calendar, the solar terms are 15° each along the ecliptic and it can be used as a solar calendar. Nevertheless, the length of the climate term near the perihelion is less than 30 days and there may be two mid-climate terms. The Shíxiàn calendar changed the mid-climate-term rule to "decide 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. (Modern) astronomical data, rather than mathematical calculations, is used.

Plans:

To optimize the Chinese calendar, astronomers have suggested several changes. Gao Pingzi (高平子; 1888–1970), a Chinese astronomer who co-founded the Purple Mountain Observatory, proposed that month numbers be calculated before the new moon and solar terms to 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 that adopted the calendar but calculate with their own time could vary from the time in China.

Chinese astronomy and Chinese astrology:

Horology, or chronometry, refers to the measurement of time. In the context of the Chinese calendar, horology involves the definition and mathematical measurement of terms or elements such observable astronomical movements or events such as are associated with days, months, years, hours, and so on. The Chinese calendar is lunisolar, like the Hindu, Hebrew, and ancient Babylonian calendars.

Basic horologic definitions include that days begin and end at midnight, and months begin on the day of the new moon. Years start on the second (or third) new moon after the winter solstice. Solar terms govern the beginning, middle, and end of each month. A sexagenary cycle, comprising the heavenly stems (Chinese: 干; pinyin: gān) and the earthly branches (Chinese: 支; pinyin: zhī), is used as identification alongside each year and month, including intercalary months or leap months. Months are also annotated as either long (Chinese: 大; lit. 'big' for months with 30 days) or short (Chinese: 小; lit. 'small' for months with 29 days). There are also other elements of the traditional Chinese calendar.

Day:

Days are Sun oriented. Day (日; rì), from one midnight to the next

Month:

Months are Moon oriented. Month (月; yuè), the time from one new moon to the next. These synodic months are about 29+¹⁷⁄₃₂ days long. This includes the Date (日期; rìqī), when a day occurs in the month. Days are numbered in sequence from 1 to 29 (or 30). And a Calendar month (日曆月; rìlì yuè), is when a month occurs within a year. Some months may be repeated.

Year:

Year (年; nián), time of one revolution of Earth around the Sun. It is measured from the first day of spring (lunisolar year) or the winter solstice (solar year). A year is about 365+³¹⁄₁₂₈ days. This includes the Calendar year (日曆月年; rìlì nián) when it is agreed that one-year ends and another begins. The year usually begins on the new moon closest to Lichun, the first day of spring. This is typically the second and sometimes third new moon after the winter solstice. A calendar year is 353–355 or 383–385 days long. Also includes Zodiac, ¹⁄₁₂ year, or 30° on the ecliptic. A zodiacal year is about 30+⁷⁄₁₆ days.

Solar terms:

Solar term (節氣; jiéqì), ¹⁄₂₄ year, or 15° on the ecliptic. A solar term is about 15+⁷⁄₃₂ days.

Planets:

The movements of the Sun, Moon, Mercury, Venus, Mars, Jupiter, and Saturn (sometimes known as the seven luminaries) are the references for calendar calculations.

• The distance between Mercury and the sun is less than 30° (the sun's height at chénshí: 辰時, 8:00 to 10:00 am), so Mercury was sometimes called the "chen star" (辰星); it is more commonly known as the "water star" (水星).
• Venus appears at dawn and dusk and is known as the "bright star" (啟明星; 启明星) or "long star" (長庚星; 长庚星).
• Mars looks like fire and occurs irregularly and is known as the "fire star" (熒惑星; 荧惑星 or 火星). Mars is the punisher in Chinese mythology. When Mars is near Antares (心宿二), it is a bad omen and can forecast an emperor's death or a chancellor's removal (荧惑守心).
• Jupiter's revolution period is 11.86 years, so Jupiter is called the "age star" (歲星; 岁星); 30° of Jupiter's revolution is about a year on earth.
• Saturn's revolution period is about 28 years. Known as the "guard star" (鎮星), Saturn guards one of the 28 Mansions every year.

The Constellations:

The Big Dipper is the celestial compass, and its handle's direction indicates, or some said determines the season and month.

Chinese constellations: Twenty-Eight Mansions and Lunar station

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, (紫微), Supreme Palace (太微), and Heavenly Market. (天市) The eastern mansions are 角, 亢, 氐, 房, 心, 尾, 箕. Southern mansions are 井, 鬼, 柳, 星, 張, 翼, 轸. Western mansions are 奎, 婁, 胃, 昴, 畢, 參, 觜. Northern mansions are 斗, 牛, 女, 虛, 危, 室, 壁. 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 (袁天罡) matched the 28 mansions, seven luminaries and yearly animal signs to yield combinations such as "horn-wood-flood dragon" (角木蛟).

(Adapted and edited by jb lim from information in Wikipedia)