Chinese Calendar the Lunisolar Calendar — Formation, Records, Elements, Facts, and Utilizations
Today in China, people use two calendars concurrently.
One is the Gregorian Calendar, introduced in 1912 and has been in use to better connect with the international world.
The other is the Chinese Calendar, which originated in the Xia Dynasty (2070 BC — 1600 BC) and has been revised and improved several times in history.
The Chinese Calendar is also called the Agriculture Calendar or Nongli, noting the movement of the sun and moon. It includes 12 months and 24 Solar Terms, serving as an accurate guide to agricultural activities.
Today, all traditional Chinese Festivals are based on the Chinese Calendar, and many people still celebrate their Nongli birthdays.
Movement of the Moon — 12 Months
In ancient times, people observed the periodic movement of the moon, prompting them to note the dates and months corresponding to the different phases, from crescent to full moon.
The moon's wax and wane period, usually 29 or 30 days long, constitutes a month, and 12 months make up a year.
This system is known as the Yin or Lunar Calendar, where each month is represented by a specific Lucky Flower with special cultural meanings.
However, they also realized that the movements of the moon and the sun are slightly different: 12 cycles of the moon's wax and wane take over 350 days, while the Earth's revolution lasts around 365 days.
This disparity is a significant flaw that renders the Yin or Lunar Calendar inaccurate in guiding agricultural activities.
Movement of the Sun — 24 Solar Terms
The sun plays a crucial and influential role in agricultural activities; therefore, learning about the sun's movement is very important.
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 noting the Winter Solstice, which has the longest shadow, the Summer Solstice was soon discovered.
Centuries later, the Spring and Autumn Equinoxes were recorded, marking the days when the day and night are of equal length.
The documentation of these four seasonal boundaries has continued since then.
Restored Ancient Chinese Observatory of Taosi Site of Longshan Culture (Around 2500 BC — 2000 BC) in Shanxi Province.
Until 104 BC, 24 Solar Terms had been formed and documented.
The 24 Solar Terms correspond to the sun’s positions in the ecliptic; every 15° apart along the ecliptic, there is a solar term representing the season, temperature, and various 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.
Each Solar Term has an exact date, precise to the second, along with a poetic name.
Combination of Lunar-Solar Systems — Chinese Calendar as the Lunisolar Calendar
Taking the movement of the sun and moon into consideration, there are 12 Lunar Months and 24 Solar Terms each calendar year.
Therefore, generally, there are 2 Solar Terms in every Lunar Month.
However, due to the different movement periods of the moon and the sun, there are times when only 1 Solar Term occurs in a Lunar Month.
In such cases, a Leap Month is added to that year.
Within this system, there are approximately 7 Leap Months 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 Nongli, which can clearly note dates and efficiently guide agricultural activities.
Sexagenary Cycle — Record and Count System of Chinese Calendar
The Sexagenary Cycle (Ganzhi), or Heavenly Stems and Earthly Branches (Tiangan Dizhi), is the system used to count and record in the traditional calendar, Astrology, medication, Fengshui, and divination.
It was formed no later than the 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, the other five bright planets have been documented as essential 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 compose 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 as there are 12 months in a year, we have 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 their different meanings, 6 are Yin, and 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 with the same Yin or Yang can compose a symbol that is 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. However, a Yang Heavenly Stem + a Yin Earthly Branch cannot create a symbol.
According to this system, there are 60 combinations in the Sexagenary Cycle, hence the 60-year cycle.
Utilizations of the Chinese Calendar or Nongli
Historically, the Chinese Calendar was used to note dates and times and guide agricultural activities.
Today, many Chinese still celebrate their birthdays based on the traditional calendar.
Some people would celebrate birthdays twice a year, one in the Chinese Calendar and one in the Gregorian Calendar.
In Traditional Weddings, some people would choose their date through divination, which is also based on the Chinese Calendar.
A 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 or Chinese New Year: 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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