The Chinese Calendar

Time is a unique concept that many people think of as an objective reality. However, nothing could be further from the truth. Time can be viewed from various perspectives and is, among other things, a cultural construct. This means that the way we perceive a concept like time is culturally determined. This relationship is also reciprocally valid. The way we interpret time has an impact on the development of culture. Cultural temporal orientation is of vital importance as it serves as a mirror to understand the deeper value systems and philosophies of a society. One could argue that our lifestyle is partly determined by this background. Menyu Li (4) provides a comprehensive overview of how this has been established in Western and Eastern cultures.

pocket watch in the sandWithin our own culture, most elements can be traced back to the origins of Greek culture and philosophers such as Plato and Aristotle. Firstly, there was the assumption that time has an overwhelming, if not all-determining, impact on our lives, approaching time from a physical component. Aristotle defined time as a measurable object in motion. While Plato considered the object (phenomenon) as unreal, under Aristotle, the physical aspect of existence was assigned more authenticity.

Time became something measurable within the physical object, where time follows a linear movement.

This was further adopted by influential figures throughout history. Time was used to measure the speed of an object in motion. Time was interpreted from the perspective of the physical object. This physical interpretation of absolute time as the object in motion became the predominant view of time within Western culture—materiality and linearity. This interpretation has certain consequences for how we perceive the world. Time is seen as a linear entity, something absolute with a certain regularity. These characteristics can clearly be seen in the development of the industrial revolution. Since time is a (linear) passing entity, we do not want to waste it under any circumstances. Time holds a prominent place in our lives. We live by the clock. We are future-oriented, primarily concerned with where that linear time is heading, bound by its rules. This focus on time and the physical aspect from which it is perceived is reflected in how we conduct ourselves in our existence. Our focus on materiality is a typical Western characteristic, where we must use all our time as efficiently and effectively as possible to create that material world.

However, traditional Chinese culture looks at time in a very different way. It is less absolute and more subjective and relative. It has flexible characteristics, unlike Western laws. Two important influences on this perspective are Confucianism and Daoism. An important difference is that Chinese culture sees time more as a cyclical phenomenon rather than a linear one. Therefore, there is less emphasis on the future per se. Confucius lived in a time of emerging wars and moral decline, so it was more important for him to look back at how things could be improved. This aspect is reflected in how we practice medicine. In Western culture, we are primarily focused on developing new techniques and medicines, gaining new insights into the workings of the human body. In the study of Chinese medicine, however, great value is placed on understanding classical texts and acquiring the skills of the ancient masters. Another important aspect was the flexible nature, emphasizing the importance of “good timing” for every task or life event. This is still clearly evident in modern times, for example, in the search for a suitable date for marriage, arranging a funeral, or starting a business.

Daoism, in particular, brought the aspect of relativity to the forefront. With its founders Lao Zi and Zhuang Zi, we see that breaking barriers is an important part of it, being boundless and free from various limitations, including time. The pursuit of immortality is a good example of this. What is a long life? For an ordinary mortal, their life is long compared to that of a mayfly, but for a wise person of 800 years, a 100-year lifespan is just like a short season. And what can we say about a tree that has stood for 8000 years? It is all relative. Zhuang Zi aimed to live a life free from limitations, both in time and in place. In this way, time became a non-dominant force in the perception of the Daoist. Enjoying freedom and leisure time, living a carefree existence where one is inclined to prioritize the enjoyment of play and conversation with friends and family over the pursuit of a specific physical goal in the future. This tendency is gradually disappearing as the Western pursuit of success becomes more ingrained in Eastern culture. However, conversely, as Eastern thinking becomes assimilated in our culture, there is also an increasing focus on spending our time freely and carefreely.


When we talk about time, two elements immediately come to the forefront: the clock and the calendar. Given that the perception of time is culturally determined, it won’t surprise you that the development of calendars differs across cultures. But before we delve into the calendar itself, let’s take a step back to the basics. The foundation of time lies in the study of astronomy, which examines all celestial bodies beyond Earth’s atmosphere. Astrology, on the other hand, is the study of the impact of these celestial bodies on human destiny.

In Aslaksen’s article (1), we see that within astronomy, the Earth rotates in an elliptical orbit around the Sun. It does so at a specific inclination. Along this orbit lie four important points known as the seasonal markers. The point at which the Earth passes closest to the Sun is called the perihelion, better known as the summer and winter solstice. The point at which the Earth is farthest from the Sun is called the aphelion, the equinox. Equinox, derived from Latin, roughly translates to “equal night and day.” Additionally, Kepler’s Law states that the Earth’s speed changes as it moves closer to or farther from the Sun. Moreover, the average speed decreases over time due to the Earth’s rotational slowdown. As a result, each year becomes shorter by about half a second per century. To further complicate matters, it has been observed that the Earth’s orbit is distorted by the presence of the Moon.

In general, there are three types of calendars:

  1. Solar calendar
  2. Lunar calendar
  3. Lunisolar calendar

Within the first type, the timespan of a year is measured as one complete orbit. According to Western astronomy, it is measured from the March equinox, while Chinese astronomy uses the winter solstice. This is what we call the tropical year, also known as the seasonal year or solar year. On average, it consists of about 365.242… days.

So, the solar year takes the orbit around the Sun as a reference point. As you can see, these are not whole numbers. Our Gregorian calendar has 365 days, and to account for the decimals, we have a leap year every 4 years. However, the leap year is skipped if the year is divisible by 100 (e.g., 1900). But if it is divisible by 400, then it is still considered a leap year.

A lunar calendar disregards the Sun and the tropical year, and therefore, the seasons as well. Instead, it is based on the synodic month, which is the time between one new moon and the next. On average, it lasts about 29.53 days. If you multiply that by 12 months, you get approximately 354.367… days in a year. An example of a lunar calendar is the Islamic calendar. Islamic holidays shift through the seasons because the year is 11 days shorter than the tropical year. Although the Chinese calendar is a lunisolar calendar, it also utilizes the lunar calendar and its corresponding 28 constellations. This is relevant in practices such as neidan and magical Daoism (Fu or Talisman), as well as Feng Shui and divination techniques.

A lunisolar calendar uses the months of the lunar calendar to approximate the tropical year. However, because there are 11 fewer days, they add a leap month compared to the leap day in the Gregorian solar calendar. Examples of lunisolar calendars are the Jewish and Chinese calendars. This adjustment occurs approximately every three years, with the main purpose of keeping the calendar in sync with the seasons. The question is how to calculate this adjustment. An interesting anecdote from earlier times is that people would observe nature. Were the roads dry? Were the sheep ready for slaughter? Were the fish starting their migration? If not, it was time to insert a 13th month. A more systematic approach is what we call the Metonic cycle, which is a method of making the correction based on a 19-year cycle.

It is important to note that the Chinese calendar is not strictly a lunar calendar; it is a lunisolar calendar.

chinese calendarThis means it’s a solar calendar, but instead of taking the day (sunrise) as the unit, it takes the lunar cycle (new moon). As a result, the seasons, equinoxes, and solstices remain relatively constant, but the main difference lies in the addition of the 13th or leap month (Run Yue). In these years, the constancy does not apply.

A year in the Gregorian calendar is 365 or 366 days, but in the Chinese calendar, it is 354 days (sometimes 353 or 355) or, when adding a leap month, 384 days (sometimes 383 or 385). That is quite a significant difference. This is something that the Islamic culture does not do with a lunar calendar; they maintain the standard 354 days.

As you can see, independent of the addition of a leap month, there is still variation. This is because a month does not always have the same number of days. In contrast to our own calendar, where November always has 30 days and December always has 31 days (except for February), the manifestation of the new moon can vary. The day on which the new moon occurs is considered the first day of the month. Due to this variation, a month can have 29 days (Xiao Yue) in one year and 30 days (Da Yue) in another year. There is no necessary regularity to be found. For example, you can have 3 to 4 consecutive long months (30 days).

A fundamental concept within the Chinese calendar is Jié qi, also known as solar terms.

These are seen as the timing of life events in harmony with the Yellow Path. By this, it means the orbit of the Earth around the sun. And thus, it is based on the solar calendar. It is sometimes referred to as the Farmers’ Calendar. The even numbers are considered important and are called “zhong qi.” In Western astronomy, for example, spring begins at the spring equinox, while in Chinese astronomy, it starts somewhere between the winter solstice and the spring equinox. The Jie qi are comparable to the four seasonal points (equinoxes and solstices) and each has a unique evocative name. The orbit of the Earth is divided into 24 segments, each segment having a certain quality of qi. This determines whether a particular segment is more or less suitable for certain activities. On the next page, you will find an overview of the 24 Jie qi.

TABLE: 24 JIE QI (approximate Gregorian dates – please note that these dates will vary each year but will be close) (7-p.180)

Li Chun Start of Spring Feb. 3-5
Yu Shui Spring Water Feb. 18-20
Jing Zhe Insects awaken Maa. 5-7
Chun fen Spring equinox Maa. 20-22
Qing ming Pure clarity Apr. 4-6
Gu yu Collect the rain Apr. 19-21
Li Xia Start of summer Mei 5-7
Xiao man Green buttons form Mei 20-22
Mang zhong Blossems Jun. 5-7
Xia zhi Summer Solstice Jun. 21-22
Xiao shu Minor heat Jul. 6-8
Da shu Major heat Jul. 22-24
Li qiu Start of fall Aug. 7-9
Chu shu Heat dissolves Aug. 22-24
Bai lu White dew Sep. 7-9
Qiu fen Fall equinox Sep. 22-24
Han lu Cold dew Okt. 8-9
Shuang Jiang First frost Okt. 23-24
Li dong Start of Winter Nov. 7-8
Xiao xue Light snow Nov. 22-23
Da Xue Big snow Dec. 6-8
Dong zhi Winter solstice Dec. 21-23
Xiao han Light cold Jan. 5-7
Da han Great cold Jan. 20-21

A fundamental concept that is associated with the origin of the Chinese calendar is the well-known Ten Heavenly Stems and Twelve Earthly Branches. Although history is always a challenging matter, we can trace the use of stems and branches back to the Shang Dynasty (1750 – 1122 BC). These ancient Chinese astrologers did not consider the orbit around the Sun, but rather the orbit of Jupiter as the cosmic basis. This orbit took approximately 12 years to complete, hence the Twelve Branches. This system was called “Ganzhi,” also known as the sixty-year cycle. It provided magicians, shamans, and physicians with insights into the specific forces that applied to a particular hour, day, month, or year.

Both the stems and branches can be classified as yin and yang. The odd numbers are yang, and the even numbers are yin. Additionally, they have associations with the Wu Xing (Five Phase Theory or Five Elements). This means that, similar to Wu Xing, there are interconnections between the stems and branches. What is referred to as a “stem-branch” is a combination of a heavenly stem and an earthly branch. There are 120 possible combinations of these, but the rule applies that only yin stems can be combined with yin branches, and the same for the yang variant. This results in a total of 60 possible combinations. A complete cycle of 60 is called a “Jia Zi.” The combinations are made as follows: 1-1, 2-2, 3-3, and so on until 10-10; then 1-11, 2-12, 3-1, 4-2, and so on. As you can see, it always pairs odd with odd and even with even, yin with yin, and yang with yang.

This system was widely used in China for counting purposes. Simply counting, regardless of what it was. We mainly know it in the context of timekeeping, not only in terms of years but also in terms of months, days, and hours. Until 1949, this was the customary system for determining dates. The division into hours is what we know from Chinese medicine as the organ clock, where each block of 2 hours (12x 2 hours) is associated not only with a specific organ but also with a branch and its corresponding Wu Xing associations.

The Ten Stems are said to have their historical origin in Chinese mythology and the existence of 10 suns. In later times, the correlation was mainly made from the five primary colors or the five natural elements or movements (once again, Wu Xing). Furthermore, reference is made to the ten-day week that served as a unit of time in earlier times. The Twelve Branches, on the other hand, are associated with the signs of the zodiac. However, this correlation is said to have emerged only since the Eastern Han Dynasty (25-220 AD). This was not the case in the first 1000 years of using the cycle. These 22 elements are represented as specific characters, serving as a guide for modern character signs. The occurrence of these signs was discovered as early as the Shang Dynasty (around 1200 BC) and was found on the famous oracle bone inscriptions. There are various speculations that suggest these signs form the basis of the origin of the Chinese language. This would imply that the language originated from a more astronomical context, as opposed to a more arithmetical context like in Mesopotamia. However, a definitive etymological explanation for these concepts has never been established.

Stems Jia Yi Bing Ding Wu
Ji Geng Xin Ren Gui
Branches Yin Mao Chen Si Wu Wei
Shen You Xu Hai Zi Chou

Over the foundation of these signs, John Steele has extensively reported. He refers to a unique way of depicting the Jia Zi as two gears that interlock. This immediately reveals the parallel with the Mesoamerican Tzolkin Cycle as well as the African Akan cycle. One notable feature of the use of the 10 terms was that they were used in reference to deceased family members. Notably, the 60-cycle served as the underlying mechanism for determining ritual offerings. An example of this method of naming is the Shang King List (approximately 1600 – 1050 BC), which lists over 30 names spanning about twenty generations. Each king on this list is named after a term in the 10-cycle. This is a unique aspect in Chinese historiography and demonstrates the close connection between the cyclical terms and the Shang Dynasty.

The theory of stems and branches appears in numerous aspects of Chinese culture. Within magical Daoism, they are important for determining the precise timing of writing Fu or talismans. Feng shui extensively utilizes them, as well as the personality characteristics of Ba Zi and the Four Pillars of Personality. This applies not only to the time division in stems and branches but, as we have seen, also to the lunar calendar and the different phases of the moon within those cycles. Each stem-branch is governed by a combination of specific qi and influences. These influences extend to various aspects of life, including societal, social, and personal realms.

Image of the symbols of the stems and branches:

symbols of stems and branchesWithin Chinese medicine, it is stated that certain techniques cannot be performed without this knowledge. This applies particularly to more traditional Daoist methods. Modern TCM, on the other hand, pays little to no attention to timing acupuncture treatments, although you may occasionally come across the organ clock. However, understanding this matter helps in better comprehending Chinese medicine. The associations of the stems with Wu Xing go beyond the five phases alone. Stems and branches are intertwined throughout the entire theory of Wu Xing and its interrelationships. This clearly demonstrates the interconnectivity of time, space, and humans. While the stems primarily relate to Wu Xing, the branches pertain to the six qi (heat, dampness, fire, dryness, cold, wind). A well-known example in acupuncture is chronoacupuncture, where Zi Wu Liu Zhu is the most renowned variant. According to these theories, each moment (stem-branch) has certain points or combinations of points that are most effective and generate a greater effect when needled. It essentially involves aligning your treatment not only with the seasons but specifically with the stem-branch of that moment. It is determined which channel (meridian) is open according to calculations using the ancient method of Na Zi Fa. Nowadays, this doesn’t have to be so complex since there are apps available that indicate the most suitable points for treatment according to various available methods.

In this article, we have seen that time is culturally determined. As Einstein said, time is relative. Each culture has its own calendar depending on its astronomical perspective. We distinguish between a solar and lunar calendar, of which the Chinese use a mixture: the lunisolar calendar. Certain aspects rely solely on the lunar calendar, while others utilize the solar calendar, of which the 24 Jie Qi are an example, representing specific time elements such as solstices and equinoxes. Another important element of the calendar is the use of stems and branches, which leads to the 60-year cycle. Although this knowledge has faded into the background, it still forms an essential part of various Chinese (pseudo-)sciences such as Feng Shui, divination, and medicine. If you want to get started, try finding out which stem and branch you were born under. It is an extremely fascinating world.



  1. Aslaksen Helmer (2006) The Mathematics of the Chinese Calendar; Department of Mathematics National University of Singapore
  2. Boltz William G. (2019) The Chinese Sexagenary Cycle and the Origin of the Chinese Writing System; From Culture and Cognition—essays in Honor of Peter Damerow; Max Plank Research Library for the History and Development of Knowledge; ISBN 978-3-945561-35-5
  3. Liu Zheng-Cai (1999) A study of Daoist acupuncture & Moxibustion; Bleu Poppy Press; ISBN 1-891845-08-X
  4. Mengyu Li (2008) The Unique Values of Chinese Traditional Cultural Time Orientation: In comparison with Western Cultural Time Orientation; Ocean University of China; Intercultural communication studies XVII.
  5. Smith Adam (2010) The Chinese Sexagenary Cycle and the Ritual Origins of the Calender; From Calendars and years II: Astronomy and Time in the Ancient and Medieval World—John M. Steele; Oxford Oxbow Books; ISBN 9781842179871
  6. Van Kervel Peter (2018) Acupunctuur Hemelse Stammen en aardse taken—Wu Yun Liu Qi—De filosofie en fysiologie van de acupunctuur; Lan Di Press; Kockengen, Nederland; ISBN 978-90-79212-17-0
  7. Wen Benebell (2016) The Tao of Craft—Fu Talismans and Casting Sigils in the Eastern Esoteric Tradition; North Atlantic Books, Berkeley, California; ISBN 9781623170660