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What Is Saju? Korean Four Pillars, Explained
Saju in one paragraph
Saju (사주) is the Korean practice of reading a birth moment as eight characters — 사주팔자, “four pillars, eight characters.” Your birth year, month, day and hour each get a pair: a Heavenly Stem on top, an Earthly Branch below. The stem of the day pillar is your Day Master, the “you” that the rest of the chart is measured against. Everything else — the five elements, the Ten Gods, the ten-year luck pillars — describes how the other seven characters treat that one. It is Korean Myeongri (명리), the same calendar tradition as Chinese BaZi, read in a Korean way.
A real chart, character by character
Explanations of Saju are easy to write and hard to check, so here is a real one. IU was born on 1993-05-16; the birth date is public and cited below, and the chart is computed by the same engine that runs our free calculator — not typed in by hand.
Her birth time is not public, so the hour pillar is left empty. Six of the eight characters are still exact — which is why a Saju reading works without a birth time, and why every claim on this page uses only those six.
Birth date source: Wikipedia
丁 (정) — Fire. This one character is the anchor. Read the other seven as things that happen to it.
What the other characters say about it
Each remaining stem is classified by how it relates to the Day Master. That relationship has a name — one of the Ten Gods. Computed live from the two stems we can trust:
- Year stem → Seven Killings 偏官
- Month stem → Companion 比肩
- Read all ten →
What each pillar governs
The four pillars are not four predictions. They are four vantage points on one life, and traditional readings assign each a stretch of time and a domain.
| Pillar | Life stage | What it describes |
|---|---|---|
| Year 年柱 | roots, early years | Family background and the era you arrived in. Its branch is the character that gives you a Korean zodiac animal. |
| Month 月柱 | youth, adulthood | Parents, upbringing, career and social role. Often the heaviest pillar in a reading, because the month decides which season your Day Master was born into. |
| Day 日柱 | the middle of life | You and your closest partner. The stem is your Day Master; the branch is called the spouse palace (일지 / 배우자궁), which is why compatibility readings look here. |
| Hour 時柱 | later years | Children, the second half of life, and what you do when nobody is watching. The only pillar that needs a birth time. |
Your Day Master is the “you”
There are ten possible Day Masters: five elements — Wood, Fire, Earth, Metal, Water — each in a yang and a yin form. A yang Wood day master (甲) reads like a standing tree; yin Wood (乙) reads like a vine. The difference is not decoration. It changes which elements support you, which drain you, and how every other character in the chart is scored.
The five elements are the grammar
Wood feeds Fire, Fire makes Earth, Earth holds Metal, Metal carries Water, Water grows Wood. Each element also keeps another in check. A Saju reading is largely bookkeeping over these two cycles: which elements crowd your chart, which are missing, and which one — the useful element (용신) — would settle it.
The Ten Gods are the sentences
Elements say what the material is. The Ten Gods (십신) say what it does to you: the same Metal is a rival, a paycheck, a boss, or a mentor depending on where it stands relative to your Day Master. This is the layer that turns a chart into a description of a person.
What Saju is not
Saju is not a Korean zodiac horoscope. Your animal sign is one character out of eight — the branch of the year pillar — so it describes at most an eighth of a chart, and it is the character a reader weighs least. Two people born in the same year routinely have opposite charts. Saju is also not a spirit speaking through a medium: a Saju reader works from a calendar and a rule set, which is why two readers agree on what the eight characters *are* even when they disagree about what to do with them.
Twelve words you will keep seeing
Korean readings use Korean vocabulary. These are the ones worth knowing.
The four pillars — the whole chart.
The eight characters. “사주팔자” is the full phrase.
The perpetual calendar the characters are looked up in.
The ten Heavenly Stems — the top character of each pillar.
The twelve Earthly Branches — the bottom character, and the zodiac animals.
The Day Master: the stem of the day pillar. You.
The day branch, called the spouse palace — read for partnership.
The five elements: Wood, Fire, Earth, Metal, Water.
The Ten Gods — how each character relates to your Day Master.
Luck pillars: the ten-year periods a chart moves through.
The useful element — the one your chart most needs.
Compatibility: two charts read against each other.
This describes the pattern in general — every chart carries it differently. The app reads the whole chart — how it moves through the years, and what to do with it.
Unlock the full readingSaju — frequently asked questions
Do I need my exact birth time to read my Saju?
No, not to start. Your year, month and day pillars are six of the eight characters, and your Day Master lives in that group — so your core reading is exact without a birth time. A birth time only adds the hour pillar, which traditionally covers children and the later half of life.
Is Saju the same thing as Chinese BaZi?
They read the same sexagenary calendar, so the eight characters come out the same. What differs is emphasis and vocabulary: Korean Myeongri leans hard on the Day Master and the useful element, and Korean practice built compatibility (궁합) into ordinary social life in a way Chinese practice did not.
What is a Day Master?
The Heavenly Stem sitting on top of your day pillar. It is one of ten characters — five elements × yin/yang — and it represents you. Every other character in the chart is graded by what it does to your Day Master: supports it, drains it, controls it, or is controlled by it.
How is Saju different from my Korean zodiac sign?
Your zodiac animal is the branch of your year pillar — one character. Saju reads all eight, and the year branch is usually the least informative of them. That is why two people born in the same animal year can be described in completely opposite ways.
Is Saju a religion?
No. It is a calendar-based interpretive system, and in Korea it is consulted by people of every religion and none — closer in social role to a personality framework or a second opinion than to a faith. Read it for self-reflection, not as instruction.
Keep reading
The Ten Gods (십신), ExplainedThe Five Elements of Korean SajuKorean Fortune Telling, Explained From the InsideSaju vs. BaZi vs. Astrology — What Is Actually Different