Heavenly Stems

In one line: The Heavenly Stems are ten ancient "code characters" the Chinese used to keep track of days and years before Arabic numerals.

What Is It?

You've probably heard of "Jia, Yi, Bing, Ding" — those are the first four of the Heavenly Stems. The full set of ten:

Jia 甲, Yi 乙, Bing 丙, Ding 丁, Wu 戊, Ji 己, Geng 庚, Xin 辛, Ren 壬, Gui 癸

Before Arabic numerals existed, people used these ten characters in rotation to label time. These ten symbols are called the Heavenly Stems (天干).

Why Does It Matter?

Each Heavenly Stem carries a Five Element attribute and a Yin-Yang attribute:

Stem	Element	Yin/Yang
Jia 甲	Wood	Yang
Yi 乙	Wood	Yin
Bing 丙	Fire	Yang
Ding 丁	Fire	Yin
Wu 戊	Earth	Yang
Ji 己	Earth	Yin
Geng 庚	Metal	Yang
Xin 辛	Metal	Yin
Ren 壬	Water	Yang
Gui 癸	Water	Yin

How to Read It in Your BaZi Chart

At the moment of your birth, each of the year, month, day, and hour was assigned one Heavenly Stem — four in total. These form the "stem half" of the Four Pillars (四柱).

For example, if your Day Pillar is "Jia Chen 甲辰," then Jia 甲 is your Day Master — the character that represents you yourself.

All BaZi analysis revolves around the Day Master: is it strong or weak? What does it favor? What does it avoid?

Common Misconceptions

❌ "The Heavenly Stems are the same thing as the Five Elements" — the stems are symbols; the Five Elements are the attributes those symbols carry. ❌ "The ten stems represent ten days" — the ancients did use stems to count days, but BaZi analysis is far more complex. ❌ "More stems in a chart means a better chart" — the stems only make sense when read together with the Earthly Branches.

📜 Classical source: Di Tian Sui (《滴天髓》) — "Jia Wood towers to the sky; to be born, it needs Fire." 🔗 Next: Earthly Branches