The Heavenly Stems and Earthly Branches: The Alphabet of BaZi
In a Nutshell
The ten Heavenly Stems and twelve Earthly Branches are the alphabet of BaZi: paired one-to-one, they form the sixty pairs of the sexagenary cycle, and a BaZi chart is simply four such Stem-Branch pairs.
Quick facts
| Item | Detail |
|---|---|
| Heavenly Stems | 10: Jia, Yi, Bing, Ding, Wu, Ji, Geng, Xin, Ren, Gui |
| Earthly Branches | 12: Zi, Chou, Yin, Mao, Chen, Si, Wu, Wei, Shen, You, Xu, Hai |
| Pairings | 60 (the sexagenary cycle), then it repeats |
| Pairing rule | Yang stems pair only with yang branches; yin stems only with yin branches |
| Role in BaZi | Year, Month, Day, and Hour Pillars are each one stem + one branch |
| Day Master | The stem of the Day Pillar — the "I" of the whole chart |
The ten Heavenly Stems
Jia, Yi, Bing, Ding, Wu, Ji, Geng, Xin, Ren, Gui.
The ancients used them to count days and years — expressions like "a Jia Zi day" or "a Bing Wu year" come from this system. Each stem carries a yin or yang polarity: Jia, Bing, Wu, Geng, and Ren are yang; Yi, Ding, Ji, Xin, and Gui are yin. Memorize this split — you'll need it when you meet the Ten Gods.
The twelve Earthly Branches
Zi, Chou, Yin, Mao, Chen, Si, Wu, Wei, Shen, You, Xu, Hai.
The branches' most famous identity is the zodiac: Zi–Rat, Chou–Ox, Yin–Tiger, Mao–Rabbit, Chen–Dragon, Si–Snake, Wu–Horse, Wei–Goat, Shen–Monkey, You–Rooster, Xu–Dog, Hai–Pig. Your zodiac animal is simply the branch of your birth year.
The pairing rule: sixty combinations
Stems and branches pair up in order — yang with yang, yin with yin — starting from Jia Zi and running through to Gui Hai: sixty pairs in all, known as the sexagenary cycle, after which it repeats.
Why sixty and not 120? Because polarity must match: the yang stem Jia can only pair with yang branches (Zi, Yin, Chen, Wu, Shen, Xu), while the yin stem Yi pairs only with yin branches (Chou, Mao, Si, Wei, You, Hai). Sixty is the least common multiple of 10 and 12 — so one full Jia Zi round takes exactly sixty years. That's where the saying "one jia zi is sixty years" comes from.
Element and polarity of each stem and branch
| Stem | Jia | Yi | Bing | Ding | Wu | Ji | Geng | Xin | Ren | Gui |
|---|---|---|---|---|---|---|---|---|---|---|
| Element & polarity | Yang Wood | Yin Wood | Yang Fire | Yin Fire | Yang Earth | Yin Earth | Yang Metal | Yin Metal | Yang Water | Yin Water |
| Branch | Zi | Chou | Yin | Mao | Chen | Si | Wu | Wei | Shen | You | Xu | Hai |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Element & polarity | Yang Water | Yin Earth | Yang Wood | Yin Wood | Yang Earth | Yang Fire | Yin Fire | Yin Earth | Yang Metal | Yin Metal | Yang Earth | Yang Water |
(Wei and Chou are classed as Yin Earth — the standard convention.)
Where they sit in a BaZi chart
A BaZi chart is four Stem-Branch pairs marking your birth time: Year Pillar, Month Pillar, Day Pillar, Hour Pillar. Four pillars, eight characters. The stem of the Day Pillar is the Day Master — the reference point of the entire chart.
Heads-up: the Year Pillar changes at Li Chun (the start of spring, around Feb 4), not on Lunar New Year's Day. Born before Li Chun? You still belong to the previous year's Stem-Branch — the single most common chart-casting pitfall, explained in detail in Casting the Four Pillars.
MoZhu tip
Don't try to memorize all sixty combinations. Learn the order and polarity of the ten stems and twelve branches first — chart software does the pairing for you. Understanding *why* there are sixty matters more than reciting all sixty.
Classical sources
Traditional BaZi fundamentals; the sexagenary cycle (liu shi jia zi) is documented across classical calendrical and divination literature.
*For entertainment purposes only.*