The Alphabet
Heavenly Stems & Earthly Branches — The 22 Symbols Every BaZi Chart Is Built From
BaZi has exactly 22 symbols — 10 stems and 12 branches — and every chart is just four pairs of them. Learn the symbols and you can read the surface of any chart.
TL;DR
- The 10 Heavenly Stems (天干 tiāngān) pair each of the five elements with a yang or yin polarity. That gives you ten.
- The 12 Earthly Branches (地支 dìzhī) align with the twelve animals of the Chinese zodiac, twelve two-hour blocks, and twelve solar months.
- Every branch contains one to three hidden stems— secondary energies that aren’t visible on the chart but still influence its analysis.
- Two charts can share the same surface stems but very different hidden-stem profiles. This is why a serious reading goes deeper than the four characters everyone sees.
The 10 Heavenly Stems (天干)
The Heavenly Stems are the upper half of every pillar in your chart. Each one is a single Chinese character, and each pairs an element with a polarity. Five elements times two polarities equals ten stems. The order is canonical — the Chinese counted millennia of years using this sequence.
| # | Char | Pinyin | English | Element | Polarity |
|---|---|---|---|---|---|
| 0 | 甲 | Jiǎ | Yang Wood | Wood | yang |
| 1 | 乙 | Yǐ | Yin Wood | Wood | yin |
| 2 | 丙 | Bǐng | Yang Fire | Fire | yang |
| 3 | 丁 | Dīng | Yin Fire | Fire | yin |
| 4 | 戊 | Wù | Yang Earth | Earth | yang |
| 5 | 己 | Jǐ | Yin Earth | Earth | yin |
| 6 | 庚 | Gēng | Yang Metal | Metal | yang |
| 7 | 辛 | Xīn | Yin Metal | Metal | yin |
| 8 | 壬 | Rén | Yang Water | Water | yang |
| 9 | 癸 | Guǐ | Yin Water | Water | yin |
Read this list once and you already know more than most people who casually use the Chinese zodiac. The stem of your day pillar — your Day Master — is one of these ten, and it sets the lens for everything else in your reading.
The 12 Earthly Branches (地支)
The Earthly Branches are the lower half of every pillar. Each branch carries an element and polarity of its own — but unlike stems, branches also contain hidden stems: anywhere from one to three additional stems “stored” inside them. The hidden stems are why branches do most of the analytical heavy lifting in real chart reading.
Branches differ in how concentrated their qi is. Three of the four cardinal branches (子 Rat, 卯 Rabbit, 酉 Rooster) contain a single hidden stem — pure water, pure wood, pure metal — while the fourth, 午 Horse, contains two(Yin Fire and Yin Earth). The four “earth season” branches at the seasonal transitions (丑 Ox, 辰 Dragon, 未 Goat, 戌 Dog) each carry three hidden stems, reflecting their role as the bridge between two seasons. The corner branches that mark the start of each season (寅 Tiger, 巳 Snake, 申 Monkey) each carry three hidden stems, while 亥 Pig carries two. Refer to the table above for the exact contents of each branch. None of this is decoration — it changes how the chart is scored.
Hours map directly to branches
Your hour pillar branch is read straight off the clock, in two-hour windows. Note that the day rolls over at 23:00, not midnight, because the first 子 hour begins at 11 PM. This is also why someone born at 23:30 on a Tuesday belongs to Wednesday in BaZi terms.
| Branch | Pinyin | Animal | Time window |
|---|---|---|---|
| 子 | Zǐ | Rat | 23:00 – 00:59 |
| 丑 | Chǒu | Ox | 01:00 – 02:59 |
| 寅 | Yín | Tiger | 03:00 – 04:59 |
| 卯 | Mǎo | Rabbit | 05:00 – 06:59 |
| 辰 | Chén | Dragon | 07:00 – 08:59 |
| 巳 | Sì | Snake | 09:00 – 10:59 |
| 午 | Wǔ | Horse | 11:00 – 12:59 |
| 未 | Wèi | Goat | 13:00 – 14:59 |
| 申 | Shēn | Monkey | 15:00 – 16:59 |
| 酉 | Yǒu | Rooster | 17:00 – 18:59 |
| 戌 | Xū | Dog | 19:00 – 20:59 |
| 亥 | Hài | Pig | 21:00 – 22:59 |
Why hidden stems matter
The four characters that appear at the top of a chart are the surface stems. They are what every casual reading talks about. But every Earthly Branch in the lower row is also a small container, and inside each container sit one to three hidden stems. Two charts can have the same surface stems but very different hidden-stem profiles, which is why a serious reading goes deeper than the four characters everyone sees.
A practical example. Imagine two people with identical surface stems but one was born in a Tiger month (寅, hidden stems Yang Wood, Yang Fire, Yang Earth) and the other in a Rabbit month (卯, single hidden stem Yin Wood). On the surface they look the same. Underneath, the first person has a chart with active Fire and Earth currents that don’t appear in the surface pairing at all. The second has a clean, single-element Wood signal. The element balance, the Day Master strength score, and the favorable element analysis can all come out differently — sometimes radically — based on what is hidden where.
Hidden stems are also where most of the chart’s scoring weight comes from. Surface stems get the credit; hidden stems do the math.
Practitioner detail: main qi, penetration, and the order inside a branch
The hidden stems inside each branch are not equal. Practitioners order them as 主气 zhǔqì (main qi), 中气 zhōngqì (secondary, or middle qi), and 余气 yúqì(residual qi). The main qi is always the dominant element of the branch and the one that aligns with its own surface element — for example, Yin Wood (乙) is the main qi of Rabbit (卯). It carries the most weight in element-balance scoring. The secondary qi adds significant character. The residual is a faint trace, often described as “leftover energy from the previous season,” and counts for the least.
Different lineages weight these slightly differently, but a common scoring rule is roughly 1.0 for main qi, 0.5 for secondary, and 0.2 for residual. Our engine uses values in this range when computing element balance and Day Master strength.
The other technical concept is 透干 tòugān (penetration): when a hidden stem inside a branch also appears as a visible stem elsewhere in the same chart, that stem is said to “penetrate” to the surface. A penetrated hidden stem counts for more than a non-penetrated one, because it has somewhere to express itself in the visible chart. The reverse — 通根 tōnggēn (rooting)— is the same relationship described from the other side: a surface stem is “rooted” when its element appears as a hidden stem in any branch. A surface stem with no rooting is structurally weak no matter how prominent it looks. Rooting and penetration are half of why good practitioners read so much more out of a chart than beginners do.
How it connects
Stems and branches are the alphabet. The next layers are what those symbols mean and how they interact:
- The Five Elements — every stem and branch carries one. The substrate they sit on.
- The 10 Day Masters — your day stem is one of the ten Heavenly Stems above. That single symbol becomes the anchor of your chart.
- Clashes & Combinations — how the twelve Earthly Branches push, pull, and bond with each other. Where most life events show up.
- Reading a Chart — the workflow practitioners use once they have the eight characters in front of them.
FAQ
How is this different from the Chinese zodiac?
The Chinese zodiac (生肖 shēngxiào) uses just one of your twelve possible Earthly Branches — the year branch — and turns it into an animal label. BaZi uses all four pillars and both the stems and branches, giving you eight characters of resolution instead of one. Saying you're a 'Year of the Tiger' is to BaZi what saying you're a Sagittarius is to a full Western natal chart: a single slice of a much larger picture.
Why are there only 22 symbols when the cycle is 60?
The famous 60-year cycle (六十甲子 liùshí jiǎzǐ) is generated by pairing stems and branches in sequence. Naively, 10 stems × 12 branches = 120 combinations — but only same-polarity pairings work (a yang stem only pairs with a yang branch, a yin stem only with a yin branch). That cuts the valid combinations in half: 120 / 2 = 60. The 60-cycle is the cycle of valid pairs, not a cycle of new symbols.
What if my birth hour is exactly on a boundary like 23:00?
You shift into the next day's 子 (Zǐ) hour. The day pillar rolls over at 23:00, not midnight, because the first hour of the new day begins at 11 PM in the traditional system. So 22:59 is still the previous day's Pig hour; 23:00 is already the next day's Rat hour, and the day stem advances accordingly. This is one of the most common sources of error in calculators that copy Western midnight conventions.
Why do Earth branches contain so many hidden stems?
The four Earth branches — 辰 Dragon, 戌 Dog, 丑 Ox, 未 Goat — sit at the seasonal transitions, one between each pair of neighboring seasons. Because they bridge seasons, they store the residual energy of the previous season alongside the main Earth qi and a third related element. They function as 'storage vaults' (墓 mù in classical terms) and are usually the most analytically dense branches in any chart they appear in. When practitioners say a chart is 'unlocked' by a particular luck pillar, they often mean a luck pillar is hitting one of these storage vaults and releasing what was stored inside.
Do I need to memorize all 22 to read a chart?
Eventually, yes — the way you eventually memorized the alphabet. Before that, treat this page as a lookup table. Most beginners memorize the ten stems first (because they keep showing up as Day Masters), then the four cardinal branches, then the rest as needed. After ten or twenty charts they stop being symbols and start being faces.