Kairo
Korean Saju
Patterns before predictions
Heavenly Stems and Earthly Branches in Saju
Four zodiac animals are the visible labels on the bottom row — not the whole Saju chart underneath them.
Every Saju pillar contains one Heavenly Stem (cheon-gan, 천간, 天干) and one Earthly Branch (jiji, 지지, 地支). Ten stems and twelve branches advance together through a sixty-pair cycle used to name years, months, days and hours. Stems show one elemental-polarity symbol; branches carry seasonal and temporal structure, plus a layer of hidden stems, beyond their familiar animal names.
Understanding the two rows prevents a common mistake: reading a Saju chart as four zodiac animals.
The ten Heavenly Stems
The stems are:
| Character | Korean | Polarity and element |
|---|---|---|
| 甲 | Gap | Yang Wood |
| 乙 | Eul | Yin Wood |
| 丙 | Byeong | Yang Fire |
| 丁 | Jeong | Yin Fire |
| 戊 | Mu | Yang Earth |
| 己 | Gi | Yin Earth |
| 庚 | Gyeong | Yang Metal |
| 辛 | Sin | Yin Metal |
| 壬 | Im | Yang Water |
| 癸 | Gye | Yin Water |
The Day Stem is the Day Master. Other stems are interpreted partly through their element and polarity relationship to it.
Stems are often described as the more visible or expressed layer of a pillar. That is an interpretive convention, not a measurement of what other people can literally observe.
The twelve Earthly Branches
| Character | Korean | Animal | Primary seasonal association |
|---|---|---|---|
| 子 | Ja | Rat | Winter |
| 丑 | Chuk | Ox | Winter transition |
| 寅 | In | Tiger | Early spring |
| 卯 | Myo | Rabbit | Spring |
| 辰 | Jin | Dragon | Spring transition |
| 巳 | Sa | Snake | Early summer |
| 午 | O | Horse | Summer |
| 未 | Mi | Goat | Summer transition |
| 申 | Sin | Monkey | Early autumn |
| 酉 | Yu | Rooster | Autumn |
| 戌 | Sul | Dog | Autumn transition |
| 亥 | Hae | Pig | Early winter |
Branches are also assigned two-hour periods and directions. Their meaning in Saju extends beyond the animal label.
How ten and twelve become sixty
Stems and branches move forward one step at a time, with yang paired to yang and yin to yin. The first pair is 甲子, Gap-Ja. The sequence returns to that pair after sixty combinations.
Because the two sets have different lengths, a specific stem does not pair with every branch—only branches of matching polarity.
This sixty-pair structure is called the sexagenary cycle. A complete Saju chart contains four positions within it. The same sixty-pair calendar underlies more than one East Asian charting tradition; for how Saju's use of it differs from its closest relative, see a direct comparison.
Why the branches contain hidden stems
Traditional Saju assigns one or more hidden stems to each Earthly Branch. These represent internal elemental components associated with the branch’s seasonal development.
Hidden stems matter because the visible animal or primary element does not show the whole branch structure. They can create relationships with the Day Master and other characters.
They should not be used to make the chart endlessly flexible. A responsible reading explains which layer produced a claim rather than reaching into hidden stems only when the visible chart does not fit the story.
Combinations, clashes and other relationships
Branches can be interpreted through relationships commonly translated as combinations, clashes, harms, punishments and breaks. Stems also have combination relationships.
These labels can sound deterministic. A “clash” does not prove that two people will fight or that disaster will occur. Within the traditional model, it marks a dynamic relationship that may be read as movement, tension, change or incompatibility depending on context.
Avoid converting a technical label directly into an event prediction.
Why the Month Branch matters
The Month Branch locates the chart in a season. Season affects how readers assess the condition of the Day Master and other elements.
That gives the Month Branch more structural importance than a simple “parents” or “career” label suggests. A wrong solar-term boundary therefore alters the chart’s seasonal foundation.
Stems versus branches: a useful distinction
A simplified teaching model is:
- stems: visible, expressed layer
- branches: rooted, contextual layer
Use this as an entry point, not a law. A branch can have obvious effects in an interpretation, and a stem can be weak or unsupported. Position and relationship matter.
Three beginner errors
1. Reading only the animals
Four animals do not equal a full Saju reading. The stems, hidden stems, season and Day Master relationships are missing.
2. Treating every clash as bad
Technical tension is not a guaranteed negative event. It can coincide with change or require active management, depending on the interpretive school.
3. Memorising symbols before understanding relationships
Knowing that 甲 is Yang Wood is useful. Knowing how it functions in a specific seasonal chart is the actual interpretive task.
A better learning sequence
- Learn the ten stems and polarity.
- Learn the twelve branches and seasons.
- Understand the sixty-pair cycle.
- Locate the Day Master and Month Branch.
- Add hidden stems.
- Study relationships and only then connect them with life questions.
This sequence keeps vocabulary from turning into fortune-cookie statements.
Sources and further reading
- Korea Astronomy and Space Science Institute: calendar resources
- David J. Kim, “Fate, Fluidity, and Invention in Horoscopic Saju Divination,” The Journal of Korean Studies (2019)