Heavenly Stems and Earthly Branches: The 60 Cycles
Heavenly stems and earthly branches are the alphabet of Chinese astrology. Every bazi chart, every four pillars chart and every traditional almanac is written in them, and once you can read the ten stems and the twelve branches, the rest of the system stops being mysterious and becomes a calendar you can actually follow.
This guide explains what the heavenly stems and earthly branches are, lists all ten stems and all twelve branches with their elements and animals, and shows how they combine into the sixty-cycle that dates a birth chart. Everything here is a reference for understanding, not a set of predictions to accept on faith.
Why Every Bazi Chart Is Built from Heavenly Stems and Earthly Branches
A bazi chart is a birth date and time rewritten in the language of the traditional Chinese calendar, and that language has exactly two kinds of letters: heavenly stems and earthly branches.
The stems and branches are a dating system, not a prophecy. Ancient China marked years, and later days, using pairs of one stem and one branch, cycling through sixty combinations. This sexagenary cycle is one of the oldest continuous dating systems in the world, and it is still used alongside the familiar solar calendar today. When a reader sketches your four pillars, they are converting your birth moment into this calendar code.
The reason the system uses two kinds of characters is that they carry different information. The stem carries the element and its polarity — the ten stems are the five elements in yang and yin form. The branch carries the zodiac animal, its element, and a set of hidden stems. When a stem sits on top of a branch, the pair becomes a pillar, and four such pillars — year, month, day and hour — make the eight-character chart.
This is why the stems and branches are worth learning first. They are not just decoration; they are the letters from which the day master, the ten gods and the element balance are all spelled. The four pillars of destiny are simply these letters arranged into four columns.
The Ten Heavenly Stems and Their Elements
The ten heavenly stems are the upper characters of the chart, and each one is a single element in a single polarity. There are five elements — wood, fire, earth, metal and water — and each element appears once as yang and once as yin.
| Romanization | Element | Polarity |
|---|---|---|
| Jia | Wood | Yang |
| Yi | Wood | Yin |
| Bing | Fire | Yang |
| Ding | Fire | Yin |
| Wu | Earth | Yang |
| Ji | Earth | Yin |
| Geng | Metal | Yang |
| Xin | Metal | Yin |
| Ren | Water | Yang |
| Gui | Water | Yin |
The yang and yin split is what turns five elements into ten stems, and it matters more than a beginner might expect. Yang wood is read as a tall tree, yin wood as a flowering vine; yang fire as the sun, yin fire as a candle flame; yang earth as a mountain, yin earth as garden soil; yang metal as raw ore and weapon steel, yin metal as the polished blade and ornament; yang water as the ocean, yin water as rain and stream.
The stem of your day pillar is your day master, which is why the ten stems are the first thing a reader identifies. Every other character in the chart is then compared against that stem to produce the ten gods. You can think of the ten stems as ten possible centers of a reading, each with its own element and its own temperament.
The Twelve Earthly Branches and the Zodiac Animals
The twelve earthly branches are the lower characters of the chart, and they are the ones that carry the familiar zodiac animals. Each branch is a zodiac sign with an element and a season.
| Romanization | Animal | Element |
|---|---|---|
| Zi | Rat | Yang Water |
| Chou | Ox | Yin Earth |
| Yin | Tiger | Yang Wood |
| Mao | Rabbit | Yin Wood |
| Chen | Dragon | Yang Earth |
| Si | Snake | Yin Fire |
| Wu | Horse | Yang Fire |
| Wei | Goat | Yin Earth |
| Shen | Monkey | Yang Metal |
| You | Rooster | Yin Metal |
| Xu | Dog | Yang Earth |
| Hai | Pig | Yin Water |
The zodiac animal is the door most people enter through, but it is also the part most people over-read. Your year branch gives your zodiac sign, but that is only one of four branches in a chart, and the month, day and hour branches differ from person to person. Two people born in the same year of the horse carry different month, day and hour branches, and those differences matter more than the shared animal.
Each branch also conceals a set of hidden stems, which is why a branch can carry more than one element in a detailed reading. For a first pass, the branch's main element and its animal are enough: they tell you the season, the element and the symbolic color of that pillar.
The hidden stems matter when a reader wants precision. A branch like the dragon conceals earth, wood and water stems, while the monkey conceals metal, water and earth. This is why two people with the same visible branch can still show different element balances once the hidden stems are unfolded. Beginners can set this layer aside at first; it becomes useful only after the visible stems and branches are familiar.
How the Sixty Jiazi Cycle Is Assembled
The sixty cycle comes from pairing the ten stems with the twelve branches, and it has a rule that keeps the pairing from ever repeating until sixty combinations have passed.
The rule is that stems and branches pair by polarity: odd stems pair with odd branches, even stems with even branches. The first stem jia pairs with the first branch zi to make jia-zi, the first pair of the cycle. Because ten and twelve share a factor of two, only half of the possible combinations are used, which yields exactly sixty pairs rather than one hundred and twenty.
The sixty pairs have a fixed order, and the cycle is used to date years, months, days and hours. When the cycle reaches its end at gui-hai — the sixtieth pair — it simply starts again at jia-zi. This means the same stem-and-branch pair recurs every sixty years, sixty months, sixty days or sixty hours, depending on what is being dated.
For a birth chart, the sixty cycle is what gives the system its precision. Your year, month, day and hour are each a point in the cycle, so your four pillars are four slices of the same repeating calendar, taken at the moment you were born. That is what a free bazi calculator reconstructs when you enter your birth details.
The same sixty-cycle names every part of a chart. The year pillar is the pair for the birth year, the month pillar the pair for the birth month, the day pillar the pair for the birth day, and the hour pillar the pair for the two-hour block of the birth. Four slices of one repeating cycle, each anchored to a different unit of time, is all a birth chart is.
This also explains why the birth hour matters so much. The hour pillar advances every two hours, so missing the birth time leaves the fastest-moving pillar unknown, while the year, month and day pillars can still be fixed. A reader who asks for the birth time is not being difficult; they are asking for the last of the four letters.
Stems and Branches in the Four Pillars: A Worked Table
To see the stems and branches in action, it helps to lay out a sample four pillars chart the way a reader would.
| Pillar | Heavenly Stem | Earthly Branch | Reading |
|---|---|---|---|
| Year | Jia (Yang Wood) | Chen (Dragon) | Family background and early environment |
| Month | Bing (Yang Fire) | Wu (Horse) | Upbringing and working style |
| Day | Jia (Yang Wood) | Zi (Rat) | The self — the day master |
| Hour | Ren (Yang Water) | Shen (Monkey) | Later years and outward direction |
In this example, the day master is jia, yang wood, sitting on the rat branch. The year pillar shares the same stem, jia, which a reader would note as a strong wood influence from the early environment. The month pillar brings fire, the element wood generates, and the hour pillar brings water, the element that generates wood.
The branches add their own layer. The year branch is the dragon, the month branch the horse, the day branch the rat, and the hour branch the monkey. Each branch contributes its element and its hidden stems, so a detailed reading of this chart would weigh the wood of jia, the fire of the horse, the water of the rat and the metal of the monkey all at once.
The point of the table is that the stems and branches are not abstract symbols. They are specific, repeatable letters, and the same birth details always produce the same four pairs. That reproducibility is what makes the whole system teachable rather than secret.
One practical reason to learn the stems and branches before anything else is that every deeper layer of the system is written in them. The day master is a stem, the ten gods are stems and branches read in relation to that stem, and the luck pillars are more pairs of stems and branches laid over the birth chart as time passes. Master the twenty-two characters and their sixty combinations, and the rest of the tradition becomes a matter of vocabulary rather than arithmetic.
Clashes, Combinations and What Readers Watch For
Beyond the basic pairs, readers watch how the stems and branches interact across the chart, and the most common interactions are clashes and combinations.
Clashes occur between branches that sit opposite each other in the twelve-cycle. The rat clashes with the horse, the ox with the goat, the tiger with the monkey, the rabbit with the rooster, the dragon with the dog, and the snake with the pig. A clash between two branches in a chart is read as friction or movement in the life areas those pillars represent.
Combinations are the opposite: certain branches and stems are read as harmonizing. The six pairs of branches that combine are the rat with the ox, the tiger with the pig, the rabbit with the dog, the dragon with the rooster, the snake with the monkey, and the horse with the goat. Each pair is read as attraction and cooperation, and a pair appearing together in a chart is noted as a place where two parts of life pull toward each other.
There are also three-branch combinations, sometimes called the three harmonies. The tiger, horse and dog combine into fire; the pig, rabbit and goat combine into wood; the monkey, rat and dragon combine into water; and the snake, rooster and ox combine into metal. Each trio links three branches of the same season into a strengthened element, and a chart containing a full trio is read as carrying a concentrated version of that element.
Stems also combine. Certain heavenly stems are read as fusing into a new element when they meet, such as jia and ji fusing toward earth. These stem fusions are subtler than branch clashes and combinations, but a detailed reader checks them for the same reason: they change the element balance by turning two characters into a third force.
These interactions are the reason a bazi chart is read as a whole rather than as eight isolated characters. A chart full of clashes reads as restless and eventful; a chart full of combinations reads as smooth and connective. The stems and branches are the letters, but the reading is in how the letters relate.
The same vocabulary also shows up across other Chinese systems. The Da Liu Ren board and the Qi Men Dun Jia chart are both built on the same stems and branches, which is why learning this alphabet once unlocks several traditions at the same time.
If you want to see your own stems and branches in action, start with the day master — the single stem that anchors your chart — and work outward from there. The ten stems and twelve branches are a small alphabet, but they spell out an entire system of self-understanding.
Ready to read your own chart's letters? Open the free bazi calculator and generate your four pillars. Each pillar will show its stem and branch in English, so you can match them against the tables here and begin reading the calendar that dates your life.