Heavenly stems and earthly branches (天干地支, often shortened to Gan-Zhi) are the two interlocking cycles behind Chinese calendar labels and BaZi charts. There are ten Heavenly Stems—Jia, Yi, Bing, Ding, Wu, Ji, Geng, Xin, Ren, Gui—and twelve Earthly Branches—Zi, Chou, Yin, Mao, Chen, Si, Wu, Wei, Shen, You, Xu, Hai. When both sequences advance together, they form the sixty Jia Zi pairs used to name years, months, days, and double-hours. A Four Pillars (BaZi) chart is four of those pairs stacked, so this vocabulary is the layer under Day Master, Ten Gods, and luck pillars. Treat the lists below as a glossary for study and self-reflection, not as a prediction engine.
BaZiCalc guides are for entertainment and self-reflection. They are not fortune-telling, medical, financial, or legal advice. Keep birth data private; this article uses no personal charts and invents no client examples. Stem-branch labels do not decide career, love, health, or wealth outcomes.
Heavenly stems and earthly branches in plain language
Takeaway: Gan-Zhi is a shared naming system for time units; BaZi reuses those names as the eight characters of a birth chart.
Search results for “heavenly stems and earthly branches” are usually definition pages: name lists, a sexagenary (60) table, and a note that the pairs label years and days. Hong Kong Observatory and other calendar references present the same classical order. BaZi teachers then show how year, month, day, and hour each take one stem-branch pair—the “eight characters.”
If you want the system overview first, start with What Is BaZi? or BaZi for Beginners. For chart layout, see How to Read a BaZi Chart. This page stays on the stem-branch glossary: the ten stems, the twelve branches, how sixty pairs form, and how that map connects to a free chart on the BaZiCalc calculator.
What are the 10 Heavenly Stems?
Takeaway: each stem carries one of the Five Elements plus a Yang or Yin polarity.
The Heavenly Stems (天干) run in a fixed ten-step cycle. In English teaching they are usually written with pinyin and paired with Wood, Fire, Earth, Metal, or Water. Yang stems sit in the odd positions of the cycle; Yin stems sit in the even positions. That polarity matters later when readers talk about Day Master strength or combination rules, but the first job is simply to memorize the order and element.
| # | Stem | Pinyin | Element | Polarity |
|---|---|---|---|---|
| 1 | 甲 | Jia | Wood | Yang |
| 2 | 乙 | Yi | Wood | Yin |
| 3 | 丙 | Bing | Fire | Yang |
| 4 | 丁 | Ding | Fire | Yin |
| 5 | 戊 | Wu | Earth | Yang |
| 6 | 己 | Ji | Earth | Yin |
| 7 | 庚 | Geng | Metal | Yang |
| 8 | 辛 | Xin | Metal | Yin |
| 9 | 壬 | Ren | Water | Yang |
| 10 | 癸 | Gui | Water | Yin |
When people say “Jia Wood Day Master,” they mean the day stem is Jia. Wood, Fire, Earth, Metal, and Water here are the same Five Elements family discussed in Five Elements in BaZi. Day-stem profiles such as Jia Wood Day Master and Yi Wood Day Master zoom into one stem; this page keeps the full ten-stem map.
What are the 12 Earthly Branches?
Takeaway: branches name the twelve animals, the civil months in many BaZi month rules, and the traditional double-hours (shichen).
The Earthly Branches (地支) form a twelve-step cycle. Popular culture knows them mainly through the Chinese zodiac animals. In calendar and BaZi practice they also mark months and two-hour periods. Animal labels are folk mnemonics; the branch character (Zi, Chou, Yin…) is the technical name that appears in charts.
| # | Branch | Pinyin | Animal | Typical shichen (local clock) |
|---|---|---|---|---|
| 1 | 子 | Zi | Rat | 23:00–01:00 |
| 2 | 丑 | Chou | Ox | 01:00–03:00 |
| 3 | 寅 | Yin | Tiger | 03:00–05:00 |
| 4 | 卯 | Mao | Rabbit | 05:00–07:00 |
| 5 | 辰 | Chen | Dragon | 07:00–09:00 |
| 6 | 巳 | Si | Snake | 09:00–11:00 |
| 7 | 午 | Wu | Horse | 11:00–13:00 |
| 8 | 未 | Wei | Goat | 13:00–15:00 |
| 9 | 申 | Shen | Monkey | 15:00–17:00 |
| 10 | 酉 | You | Rooster | 17:00–19:00 |
| 11 | 戌 | Xu | Dog | 19:00–21:00 |
| 12 | 亥 | Hai | Pig | 21:00–23:00 |
Your year animal is the Year Branch only. A full chart still needs month, day, and hour pillars. Births near Lunar New Year (and, in many BaZi schools, near Li Chun) can shift which year branch applies—see Chinese Zodiac vs BaZi and Birth Time and Four Pillars for boundary and hour detail. For a single-animal deep dive, Year of the Rabbit shows how Mao years work as cultural labels.
How the 60 Jia Zi cycle is built
Takeaway: stems and branches step forward together; after sixty pairs the sequence returns to Jia-Zi.
Pair the first stem with the first branch, the second with the second, and keep going. The list begins Jia-Zi, Yi-Chou, Bing-Yin, Ding-Mao… and ends Gui-Hai before restarting. Because ten and twelve share a factor of two, the least common multiple is sixty, not one hundred twenty. Jia (odd) only meets odd-positioned branches; Yi (even) only meets even-positioned branches. Half of the imaginary 10×12 grid never appears.
That sixty-name list is the sexagenary cycle, often called Jia Zi after its first term. Calendar years such as 2026 Bing-Wu (Fire Horse in popular wording) are simply one slot on that list. The same cycle also labels days historically and, with derived rules, months and hours. You do not need to memorize all sixty on day one; you do need to know that every pillar name is one legal pair from this list.
| # | Pair | # | Pair | # | Pair |
|---|---|---|---|---|---|
| 1 | Jia-Zi | 2 | Yi-Chou | 3 | Bing-Yin |
| 4 | Ding-Mao | 5 | Wu-Chen | 6 | Ji-Si |
| 7 | Geng-Wu | 8 | Xin-Wei | 9 | Ren-Shen |
| 10 | Gui-You | 11 | Jia-Xu | 12 | Yi-Hai |
How stems and branches form a BaZi chart
Takeaway: four pillars = four stem-branch pairs for year, month, day, and hour.
BaZi literally means “eight characters”: four stems on top and four branches underneath. Each column is one time unit:
- Year pillar — year stem + year branch (the branch is the familiar zodiac animal).
- Month pillar — month stem + month branch (month branch follows seasonal/civil month rules; month stem is derived from the year stem in classical tables).
- Day pillar — day stem + day branch. The day stem is the Day Master, the reference point for most beginner readings.
- Hour pillar — hour stem + hour branch (branch from shichen; stem derived from the day stem).
Classical month-stem and hour-stem derivation tables (year stem → month stems; day stem → hour stems) are what calendar authorities summarize when they say stems of the month follow the year, and stems of the hour follow the day. Software and lookup tables implement those rules so you do not hand-calculate every time. Once the four pairs are known, readers move to Day Master identity (What Is a BaZi Day Master?), element balance, and later topics such as combinations.
Unknown birth time usually means a missing or uncertain hour pillar. That is a data limit, not a moral failure—see the birth-time guide linked above before forcing an hour you do not have.
Stem vs hidden stem: what beginners mix up
Takeaway: the visible stem sits on top of a pillar; hidden stems are element qualities stored inside a branch.
A chart printout shows eight characters. Hidden stems are an extra lookup layer: each Earthly Branch can contain one or more Heavenly Stem qualities (main qi and, for many branches, residual qi) that are not written as a ninth visible row in simple UIs. They refine element counts and Ten Gods detail after the open stems and Day Master are clear.
Do not confuse “learning the ten stems” with “reading hidden stems.” Master the open Gan-Zhi names first, then open BaZi Hidden Stems when you need the branch interiors. Likewise, combination and clash language acts on branches and stems with conditions—see BaZi Combinations and Clashes after the vocabulary here feels stable.
How to use this glossary with a free chart
Takeaway: generate the four pillars, label each stem and branch from the tables above, then study the Day Master before advanced rules.
- Enter birth date (and time if known) on the free BaZi calculator.
- Read the year, month, day, and hour pairs aloud using the stem and branch tables on this page.
- Circle the day stem—that is your Day Master study focus.
- Note the year branch animal as cultural context only; it is one of four branches.
- When ready, continue to five elements, hidden stems, or a soft reflective report—without treating any label as a guaranteed outcome.
If a page ranks for “jia zi” or “60 jia zi cycle,” it is usually selling the same sexagenary list. Keep one mental model: ten stems, twelve branches, sixty legal pairs, four pairs per chart. Extra folklore can wait.
Month stems and hour stems: the derivation idea
Takeaway: month stems follow the year stem; hour stems follow the day stem, using fixed classical tables.
Early calendars often named months and hours by branch alone. Later practice attached stems as well. The practical rule students meet first is a lookup: given the year stem, the twelve month stems for Yin through Chou months are predetermined; given the day stem, the twelve hour stems for Zi through Hai hours are predetermined. Observatory-style references print those grids so readers can verify software output.
You rarely need to memorize every cell. You do need the mental model: branches can stand alone as seasonal or clock labels, while full Gan-Zhi pairs appear once stems are filled in. When a calculator shows Bing-Yin as a month pillar under a Jia or Ji year stem pattern, that is the table speaking—not a personality judgment.
Common mix-ups when learning Gan-Zhi
Takeaway: separate calendar nicknames, zodiac folklore, and chart mechanics before stacking advanced rules.
- Animal ≠ full chart. “Year of the Horse” names the Year Branch Wu. It does not describe month, day, or hour.
- Stem element ≠ branch animal element slogans. Popular posts sometimes assign a second element story to animals. Keep the stem’s Five Elements mapping clean first; treat folk slogans as optional color.
- Same English syllable, different characters. The stem Wu (戊, Earth) and the branch Wu (午, Horse) share a pinyin spelling in English teaching materials. In Chinese they are different characters. Always check which column you are reading.
- Sixty pairs are not sixty luck scores. Jia-Zi through Gui-Hai are names on a cycle. Ranking them as “good” or “bad” years for everyone is entertainment mythology, not something this site endorses as fact.
- Hidden stems come later. If the open eight characters are still fuzzy, pause before branch-interior tables.
A useful drill: pick any recent year label you already know (for example a Fire Horse year discussion in the news), split it into stem + branch, and locate each piece in the tables above. Then open your own chart and do the same for all four pillars. Repetition beats memorizing the entire sixty list in one sitting.
When you compare systems, remember Western sun-sign astrology and BaZi share curiosity about birth timing but use different calendars and symbols—see BaZi vs Western Astrology if that contrast is your next question. For Useful God vocabulary after pillars are solid, What Is Useful God (Yong Shen) in BaZi? is a later stop, not a substitute for learning stems and branches.
FAQ: heavenly stems and earthly branches
What does Gan-Zhi mean?
Gan-Zhi (干支) is the Chinese shorthand for Heavenly Stems and Earthly Branches together. “Gan” points to the stem cycle; “Zhi” points to the branch cycle.
How many Heavenly Stems and Earthly Branches are there?
Ten stems and twelve branches. Combined in lockstep they produce sixty repeating pairs.
What is the Jia Zi cycle?
Jia Zi is both the name of the first pair (Jia + Zi) and a common nickname for the whole sixty-pair sexagenary cycle used for years and other time units.
Is my Chinese zodiac animal an Earthly Branch?
Yes in the year-pillar sense: the animal maps to the Year Branch. Your month, day, and hour branches may be different animals entirely.
Do stems and branches predict luck?
No reliable public evidence supports using Gan-Zhi labels as guaranteed predictions for career, romance, health, or money. On BaZiCalc they are educational symbols for reflection and entertainment only.
What is a hidden stem?
A hidden stem is a stem-quality stored inside an Earthly Branch according to traditional tables. It is separate from the visible stem written on top of the pillar.
Why does BaZi need birth time?
Birth time selects the hour branch (shichen) and, through derivation rules, the hour stem. Without a trustworthy time, the hour pillar stays incomplete.
Where should I go after this page?
Generate a chart on the homepage, then read Day Master, Five Elements, and Hidden Stems in that order if you are new.
Try your chart next
You now have the stem list, the branch list, the reason there are sixty Jia Zi names, and how four pairs become a BaZi chart. Run the free calculator to see your pillars labeled in the same vocabulary. If you want a longer structured walkthrough of what is on the page, you can unlock a personal reflective report from the homepage—still for entertainment and self-reflection, with no promise of outcomes. For neighboring topics, continue with How to Read a BaZi Chart, Hidden Stems, or Strong vs Weak Day Master.