Chinese Calendar the Lunisolar Calendar — Formation, Record, Elements, Facts, and Utilization
Today in China, people use two calendars concurrently.
One is the Gregorian Calendar, introduced in 1912 and has been used till today, to better connect with the international world.
The other is the Chinese Calendar, which originated since the Xia Dynasty (2070 BC — 1600 BC), and had been revised and improved several times in history.
Chinese Calendar is also called Agriculture Calendar or Nong Li, which notes the movement of the sun and moon, includes 12 months and 24 Solar Terms, and had been used as accurate guides to agricultural activities.
Today, all traditional Chinese Festivals are based on the Chinese Calendar, and many people still celebrate their Nong Li birthdays.
Movement of the Moon — 12 Months in Chinese Calendar
In ancient times, people found that the movement of the moon was periodic, so they started to note the dates and months that correspond to the moon's different phases.
A period of the moon's wax and wane is a month, usually, 29 or 30 days long; and 12 months consists of a year.
This is named the Yin or Lunar Calendar, in which every month is represented by a kind of Lucky Flower with special cultural meanings.
However, they also realized that the movements of the moon and the sun are slightly different: 12 times' wax and wane of the moon is over 350 days, while the Revolution of Earth is around 365 days.
This disparity is a big flaw that makes the Yin or Lunar Calendar inaccurate to guide agricultural activities.
Movement of the Sun — 24 Solar Terms
The sun is significantly important and influential in agricultural activities; therefore, learning the movement of the sun is of great importance.
Around 3000 years ago, Ji Dan, a younger brother of King Ji Fa (? — 1043 BC), found and first documented the Winter Solstice, when he was trying to determine the geographical center of their kingdom by measuring the length of shadows.
After the Winter Solstice (with the longest shadow) was noted, soon the Summer Solstice was discovered as well.
Centuries later, the Spring and Autumn Equinoxes were recorded, when the day and night are of equal length.
The four seasonal boundaries were documented since then.
Restored Ancient Chinese Observatory of Taosi Site of Longshan Culture (Around 2500 BC — 2000 BC) in Shanxi Province.
Until the year 104 BC, 24 Solar Terms had been formed and clearly documented.
The 24 Solar Terms in the Chinese Calendar correspond to the sun’s positions in the ecliptic; every 15° apart along the ecliptic, there is a solar term that represents the season, temperature, agricultural and natural phenomena.
It was a perfect guide for agricultural and fishery activities in The Central Plains of China, the cradle area of ancient Chinese Civilization.
Every Solar Term has an exact date, with precision to second, and a poetic name.
Combination of Lunar-Solar Systems — Chinese Calendar the Lunisolar Calendar
Taking the movement of the sun and moon into consideration, there are 12 Lunar Months and 24 Solar Terms in each year.
Therefore, generally, there are 2 Solar Terms in every Lunar Month.
However, because of the different movement periods of the moon and the sun, sometimes there is only 1 Solar Term in a Lunar Month.
When this situation happened, a Leap Month will be added to that year.
Within this system, there are approximately 7 Leap Months in every 19 years in the Traditional Chinese Calendar.
This way, the movements of the sun and the moon are all recorded and harmonized in one lunisolar calendar, the Chinese Calendar or Nong Li, which can both note dates clearly and guide agricultural activities efficiently.
Record and Count System of Chinese Calendar — Sexagenary Cycle or Ganzhi
It was formed no later than Shang Dynasty (1600 BC — 1046 BC) and had been documented in oracle inscriptions unearthed from this era.
But why 60?
Oracle Inscriptions of the Shang Dynasty that Records The Sexagenary Cycle System — National Museum of China (Photo by Qu Jiong)
Ten Heavenly Stems or Tiangan
Except for the sun and the moon, other five bright planets had been documented as important stars in astrology: Venus, Jupiter, Mercury, Mars, and Saturn.
These five stars move toward and away from the earth periodically, with different influences and power; the approaching earth phase is the Yang, while the apart one is the Yin.
Therefore, the Five planets, each with two phases, together, they composed the Ten Heavenly Stems:
甲（jiǎ） 乙（yǐ） 丙（bǐng） 丁（dīng） 戊（wù）
己（jǐ） 庚（gēng） 辛（xīn） 壬（rén） 癸（guǐ）
Twelve Earthly Branches or Dizhi
The Ecliptic is divided into 12 sections and there are 12 months in a year, hence the 12 Earthly Branches:
子（zǐ） 丑（chǒu） 寅（yín） 卯（mǎo） 辰（chén） 巳（sì）
午（wǔ） 未（wèi） 申（shēn） 酉（yǒu） 戌（xū） 亥（hài）
Based on the different meanings, 6 of them are Yin and the other 6 are Yang.
Later, 12 Chinese Zodiac Signs were formed to represent the 12 Earthly Branches.
Combination of Heavenly Stems and Earthly Branches
A Heavenly Stem and an Earthly Branch (both are Yin or Yang) can compose a symbol, which can be used to note the year, month, date, and hour.
For instance, a Yang Heavenly Stem + a Yang Earthly Branch, or a Yin Heavenly Stem + a Yin Earthly Branch can form a symbol. But a Yang Heavenly Stem + a Yin Earthly Branch cannot form a symbol.
According to this system, there are 60 types of combinations in the Sexagenary Cycle.
Utilization of Chinese Calendar or Nong Li
In history, the Chinese Calendar had been used to note dates and times, as well as guide agricultural activities.
Today, many Chinese still celebrate their birthdays based on the Traditional Chinese Calendar. Some people would celebrate birthdays twice a year, one from the Chinese Calendar, one on the Gregorian Calendar.
In Traditional Weddings, some people would choose their date through divination, which is also based on the Chinese Calendar.
A Chinese Calendar Page with Gregorian Calendar Date, Traditional Chinese Calendar Date, Almanac, Auspicious and Inauspicious Activities.
Meanwhile, traditional festivals are based on the Chinese Calendar as well:
Spring Festival: 1st of January
Lantern Festival: 15th of January
Qingming Festival: Qingming Solar Term
Dragon Boat Festival: 5th of May
Qixi Festival: 7th of July
Ghost Festival: 15th of July
Mid-Autumn Festival: 15th of August
Chongyang Festival: 9th of September
Dongzhi Festival: Winter Solstice Solar Term
Laba Festival: 8th of December
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