Korean astrology: what saju actually is
Eight characters, four pillars, one Day Master. The same skeleton as BaZi, with a Korean reading tradition on top.
4 min read · Published 15 August 2026
The short answer
Saju (사주) is Korean four-pillars astrology, short for saju palja — 'four pillars, eight characters'. Your birth year, month, day and hour are each converted into a heavenly stem and an earthly branch, giving eight characters that are read through the five elements. It shares its mathematical base with Chinese BaZi: the same birth moment produces the same eight characters in both. What differs is the interpretive tradition Korea built on top of it, known as myeongnihak, and the questions Korean readings are typically asked.
What the four pillars are
Each pillar is a pair: a heavenly stem and an earthly branch. There are ten stems, cycling through the five elements in yang and yin form, and twelve branches, which are the animals you already know. Ten and twelve cycle together over sixty combinations — the sexagenary cycle, which has been running continuously for millennia.
Four pillars, two characters each, is eight characters. That is what palja means, and it is the whole chart.
What each pillar is read for
- Year — your wider environment, ancestry, the era you arrived into.
- Month — the season you were born into. This one carries the most weight in judging elemental balance, because season dominates.
- Day — you. The stem of this pillar is your Day Master, the reference point everything else is measured against.
- Hour — later life, what you produce, children in traditional readings. This is the pillar most people are missing, because it needs an exact birth time.
The Day Master is the whole thing
If you take one idea away, take this one. Your Day Master is the heavenly stem of your day pillar — one of ten possibilities, such as yang Wood or yin Water. It stands for you, and every other character in the chart is described by what it does to your Day Master: feeds it, drains it, controls it, or stands level with it.
Those relationships have names — the Ten Gods — and they are where the reading actually lives. Five relationships, each splitting by yin and yang, gives ten labels covering support, output, wealth, authority and peer competition. A Korean reader will tell you which of those dominates your chart and which is missing entirely, and that is a far more specific statement than any zodiac animal.
AsterNym computes this layer in full, including the stems hidden inside each branch, on your BaZi Four Pillars page.
Saju and BaZi: what actually differs
| Korean saju | Chinese BaZi | |
|---|---|---|
| The eight characters | Identical for the same birth moment | Identical for the same birth moment |
| Tradition name | Myeongnihak (명리학) | Ziping BaZi and related schools |
| Typical emphasis | Practical, direct, decision-oriented | Denser technical apparatus, more Ten Gods theory |
| Where you meet it | Cafés, apps, before weddings and job moves | Consultations, feng shui practice, date selection |
The honest summary is that saju and BaZi are the same system with different reading cultures, not two rival calculations. Anyone telling you one produces different pillars from the other for the same birth is mistaken.
Why saju is having a moment
Saju has moved from something you consulted an elder about to something on your phone. Saju cafés, dating-app compatibility features and matchmaking services have made it culturally routine in Korea in a way Western astrology is only approaching elsewhere.
It also asks a question Western astrology largely does not: what element are you short of, and what would balance you. That framing — deficiency and excess rather than personality type — travels well, which is part of why the interest has spread.
What saju will not tell you
It will not tell you when you will die, whether you will get ill, or the date you will marry, whatever a reading claims. Traditional saju does contain material addressing all three, and that material has no evidential basis. A practitioner willing to give you a date for any of them is telling you something about themselves, not about your chart.
For what a chart can and cannot support, see what your birth chart cannot tell you about marriage, and our published refusals.
Common questions
- What is saju?
- Saju is Korean four-pillars astrology, short for saju palja, meaning 'four pillars, eight characters'. Your birth year, month, day and hour are each converted into a heavenly stem and an earthly branch, producing eight characters that are interpreted through the five elements.
- Is saju the same as Chinese BaZi?
- The calculation is the same: an identical birth moment produces identical eight characters in both systems. What differs is the interpretive tradition, known in Korea as myeongnihak, and the typical emphasis of a reading. Saju readings tend to be practical and decision-focused.
- Do I need my exact birth time for saju?
- For the full chart, yes. The hour pillar is one of four and cannot be computed without a birth time, so a timeless chart is missing a quarter of its characters. The other three pillars are exact from the date alone.
- What is a Day Master in saju?
- The Day Master is the heavenly stem of your day pillar — one of ten, such as yang Wood or yin Water. It represents you, and every other character in the chart is interpreted by its relationship to it. It is the single most important element of a saju reading.