Complete Guide to the 10 Heavenly Stems
The Heavenly Stems (천간, Cheongan; 天干; also called "Celestial Stems") are the ten characters that carry heaven's energy through the chart: 甲乙丙丁戊己庚辛壬癸 — Gap, Eul, Byeong, Jeong, Mu, Gi, Gyeong, Shin, Im, and Gye. This is shared vocabulary across Korean Saju and Chinese BaZi — the same system read in two languages — so if you have seen the "Ten Heavenly Stems" in a BaZi context, these are the exact same ten. In Saju they sit in the "heaven" layer of the pillars, the visible, expressed side of your nature. Your Day Stem (日干) is the single most important of them all: it is your Day Master (日主), the character that literally means "you" in the chart. Know your stem, and you begin to know yourself.
For how the Stems pair with the Earthly Branches and how the Korean and Chinese terms line up, see the Saju–BaZi glossary.
The ten stems are not ten random symbols. They are simply the five elements (Wood, Fire, Earth, Metal, Water), each split into a Yang and a Yin form. That is why there are exactly ten — five elements times two polarities. The grid below lays the whole family out at a glance.
The Ten Stems at a Glance
| Stem | Pinyin | Element + Polarity | Classic Imagery |
|---|---|---|---|
| 甲 Gap | Jiǎ | Yang Wood | Tall tree, towering oak |
| 乙 Eul | Yǐ | Yin Wood | Vine, grass, flower |
| 丙 Byeong | Bǐng | Yang Fire | The sun |
| 丁 Jeong | Dīng | Yin Fire | Candle, lamplight |
| 戊 Mu | Wù | Yang Earth | Mountain |
| 己 Gi | Jǐ | Yin Earth | Field, garden soil |
| 庚 Gyeong | Gēng | Yang Metal | Blade, raw ore |
| 辛 Shin | Xīn | Yin Metal | Jewel, refined gem |
| 壬 Im | Rén | Yang Water | Ocean, great river |
| 癸 Gye | Guǐ | Yin Water | Rain, dew |
Notice the rhythm: each element appears twice, first in its bold, outward Yang form, then in its soft, inward Yin form. Yang Wood is the oak that pushes upward; Yin Wood is the vine that winds and adapts. Yang Fire is the sun that lights a whole sky; Yin Fire is the candle that warms one room. This pairing is the key to reading every stem.
Yang Stems (陽干) — Active Force
Gap Wood (甲 = Yang Wood; Gap, Jiǎ) — The Towering Oak
Picture an ancient oak refusing to bend. Gap Wood stands upright, leads naturally, and carries a fierce sense of justice. Once committed to a direction, it is almost unmovable.
BTS RM (Kim Namjoon) embodies this — an unwavering team anchor, fearless on global stages, Gap Wood leadership made visible.
Byeong Fire (丙 = Yang Fire; Byeong, Bǐng) — The Blazing Sun
Solar energy personified. Byeong Fire radiates: passionate, bright, magnetic. A crowd only feeds this fire, and hiding is simply not in its vocabulary.
Son Heung-min burns with Byeong Fire — explosive presence on the pitch, that infectious smile, pure solar charisma.
Mu Earth (戊 = Yang Earth; Mu, Wù) — The Mountain
An unmovable mountain. Mu Earth holds everything and stabilizes everyone. Reliability incarnate — others lean on this pillar without thinking twice.
Gyeong Metal (庚 = Yang Metal; Gyeong, Gēng) — Tempered Steel
Sharp, decisive, allergic to injustice. Gyeong Metal cuts through nonsense with judgment like a blade. Reform and transformation are this energy's calling.
Im Water (壬 = Yang Water; Im, Rén) — The Vast Ocean
Deep wisdom, endless vision. Im Water flows around any obstacle, absorbs infinite knowledge, and thinks in vast scales. This is the strategist's stem.
Yin Stems (陰干) — Receptive Power
Eul Wood (乙 = Yin Wood; Eul, Yǐ) — The Climbing Vine
Do not confuse flexibility with weakness. Eul Wood bends but never breaks — a resilient vine that outlives rigid trees. Soft leadership that quietly gets everywhere.
Jeong Fire (丁 = Yin Fire; Jeong, Dīng) — The Intimate Flame
Candle warmth, not bonfire heat. Jeong Fire carries delicate sensitivity, a literary soul, an intellectual glow. A small light with profound impact.
IU (Lee Ji-eun) is quintessential Jeong Fire — music that feels like candlelight, gentle yet soul-penetrating.
Gi Earth (己 = Yin Earth; Gi, Jǐ) — Nurturing Soil
Receptive, fertile, embracing. Gi Earth feeds everything without fanfare. Practical and meticulous, quietly essential to those around it.
Shin Metal (辛 = Yin Metal; Shin, Xīn) — The Polished Jewel
Refined beauty meets sharp precision. Shin Metal obsesses over aesthetic perfection — a soft exterior over an uncompromising core.
Gye Water (癸 = Yin Water; Gye, Guǐ) — Morning Dew
Quiet contemplation and intuitive wisdom. Gye Water enriches from hidden places — the morning dew that nourishes the field before anyone wakes.
How Stems Combine (天干合)
Stems do not act alone. When certain pairs meet, they form a stem combination (天干合), a kind of magnetic attraction between complementary energies. The five classic pairs are 甲己, 乙庚, 丙辛, 丁壬, and 戊癸. Each Yang stem bonds with a specific Yin stem five places away, and when the conditions are right the pair can even transform into a new element. These combinations shape relationships, cooperation, and turning points in a chart, which is why reading the stems together — not just one by one — is the mark of real analysis.
Rooted in the Classics
The stems anchor all three great texts of the tradition. Ziping Zhenquan (子平真詮) builds its structure theory on how the Day Master relates to the other stems; Dripping Water Essentials (滴天髓) opens with poetry on the nature of heaven and earth flowing through these very characters; and The Sea of Fate (窮通寶鑑) reads each Day Master season by season. Learn the ten stems well and every classic becomes easier to open.
Curious about your own Day Master? Find out at Saju Analysis.