A plain-language definition for anyone researching heavenly stem, what it is, where it comes from, and how practitioners use it.
85 plain-language definitions · Cited sources · Persona-authored
By Master Wei Lin · Updated August 3, 2026
Chinese Metaphysics Scholar
What is heavenly stem?
The ten Heavenly Stems (天干 Tiān Gān) are the upper character of each pillar in a BaZi chart. They represent the five Wu Xing elements in Yin and Yang form, 甲 (Yang Wood) through 癸 (Yin Water), and form half of the sexagenary cycle used to count Chinese years, months, days, and hours.
The ten stems are Jiǎ (甲 Yang Wood), Yǐ (乙 Yin Wood), Bǐng (丙 Yang Fire), Dīng (丁 Yin Fire), Wù (戊 Yang Earth), Jǐ (己 Yin Earth), Gēng (庚 Yang Metal), Xīn (辛 Yin Metal), Rén (壬 Yang Water), and Guǐ (癸 Yin Water). Each represents an archetype: Yang Wood as the towering oak, Yin Wood as the climbing vine, Yang Fire as the sun, Yin Fire as the candle, and so on.
The Day Master of a BaZi chart is one of these ten stems, and the chart's interpretation depends entirely on which one. The classical sources also use the stems in time-counting, combined with the twelve Earthly Branches, they produce the 60-character sexagenary cycle used for years, months, days, and hours.
The ten Heavenly Stems appear in oracle-bone inscriptions from the Shang dynasty (around 1300 BCE), making them one of the oldest known Chinese counting systems. They were systematized into BaZi by Xu Zi-ping (徐子平) in the 10th century, and the Yuan Hai Zi Ping describes each stem in detail. Modern lineage holders including Joey Yap and Master Raymond Lo continue to publish on the stems.
In BaZi, the four Heavenly Stems of a person's chart (one per pillar) describe the visible expression of their qi. The Day Master is the most important; the other three stems modify, support, or pressure it. Reading the stems together is the second step of any BaZi reading, after computing the chart.
In date-time counting, the stems pair with the branches to produce a 60-day cycle, a 60-year cycle, a 60-month cycle, and a 60-hour cycle (called liushijiazi 六十甲子). Traditional Chinese almanacs (Tong Shu) use these cycles throughout.
These glossary terms are closely connected to heavenly stem:
Ten (十天干 shí tiān gān). The five Wu Xing elements (Wood, Fire, Earth, Metal, Water) each appear as a Yang and a Yin stem.
Stems are the upper character of a Chinese date-time pillar, representing the ten Yin-Yang Wu Xing variations. Branches are the lower character, representing the twelve animal signs. A complete pillar has one stem and one branch.
Yang Wood is the first Heavenly Stem. The classical sources describe it as 'the tree that touches heaven' (甲木參天), upright, decisive, hard to bend. People with Yang Wood as their Day Master are typically read as principled, ambitious, and somewhat stubborn.
Each year, month, day, and hour has one stem and one branch. The 10 stems and 12 branches combine to produce 60 unique pillars (lcm(10,12)=60), repeating every 60 of whatever unit, years, months, days, or hours.
Share Your Result
Vertical 9:16 format, perfect for Instagram Stories or TikTok. Opens in a new tab; long-press or right-click to save.
Free: how to choose a stone when everything looks appealing, the care matrix that tells you what is safe in water and what is not, and a first intention practice you can actually keep.
We respect your inbox. Unsubscribe anytime.