60Gapja / What is Saju
What is Saju? The Korean Four Pillars, explained
Saju (사주), Saju Palja (사주팔자), Four Pillars of Destiny — the same thing under three names.
Saju (사주, "four pillars") is the Korean system for reading a person from the exact moment of birth. The birth year, month, day and hour are each converted into one heavenly stem and one earthly branch, giving eight characters in total, which is why the full name is Saju Palja (사주팔자, "four pillars, eight characters"). A reader interprets the balance of the five elements among the eight characters, with the day stem standing for the person, and adds ten-year and yearly luck cycles to describe timing.
The four pillars
| Pillar | Korean | What it is built from | Traditionally stands for |
|---|---|---|---|
| Year pillar | 연주 (年柱) | The lunar-solar year, which begins at Ipchun (입춘, start of spring, around February 4), not on January 1 | Ancestry, early life, the wider environment |
| Month pillar | 월주 (月柱) | The solar term (절기) the birth falls in; the month changes on the term, not on the 1st | Parents, career and social life; the pillar readers weigh most |
| Day pillar | 일주 (日柱) | The day in the 60-day cycle; the day stem is the person | The self and the spouse |
| Hour pillar | 시주 (時柱) | The two-hour block of birth in true solar time | Children, later life |
Stems, branches and the sixty-year cycle
Each pillar pairs one of ten heavenly stems (천간) with one of twelve earthly branches (지지). Every stem and every branch belongs to one of the five elements: wood, fire, earth, metal and water. The stems and branches combine in a fixed order into sixty pairs, and the first pair, Gapja (갑자), gives this studio its name. The same sixty-pair cycle counts years, months, days and hours, which is why a Saju chart can be written for any moment.
The day master
The day stem (일간) is the character that represents the person being read. Every other character in the chart is described by its relationship to the day stem: the element that produces the day master, the element the day master produces, the element the day master controls, the element that controls the day master, and the same element. Korean readers call these relationships the ten gods (십신). A chart with a strong day master and a chart with a weak day master are read in opposite ways, so establishing the day master's strength is the first step of any reading.
Luck cycles
A Saju chart is not static. From the month pillar, a reader derives a sequence of ten-year luck pillars (대운) that begin at an age fixed by the distance from the birth to the nearest solar term. Each calendar year adds a yearly pillar (세운) on top. Most of what a Saju reading says about timing comes from how these moving pillars interact with the eight fixed characters.
How Saju differs from a horoscope
- A Western horoscope places planets against the zodiac. Saju uses no planets; the chart is a calendar calculation based on the sun's position in the year and the day and hour cycles.
- A sun sign is one of twelve. A Saju chart has 518,400 possible combinations of the four pillars before luck cycles are added.
- Saju treats the hour of birth as a full pillar, so two people born on the same day can have clearly different charts.
Where Saju comes from
The Four Pillars method was systematised in China during the Song dynasty and is known there as BaZi (八字, "eight characters"). Korea adopted the method and developed its own schools of interpretation, terminology and calendar conventions. The calculation is shared; the reading traditions differ. Saju vs BaZi covers the differences that matter in practice.
What you need to get a Saju chart
A Saju chart needs the birth date, the birth time to within an hour or so, and the birth place. The place matters because the hour pillar is defined by the sun's position, not by the clock: why birth time and place matter. If the time is unknown, a reader can still work with three pillars, but the hour pillar and part of the luck-cycle timing are lost.
See how a Saju calculator builds the chart
Frequently asked questions
- What does Saju mean in Korean?
- Saju (사주, 四柱) literally means "four pillars". The full term Saju Palja (사주팔자, 四柱八字) means "four pillars, eight characters", because each pillar is written with two characters.
- Is Saju the same as Korean astrology?
- Saju is often translated as Korean astrology because it reads a person from the moment of birth, but Saju uses no planets or constellations. Saju is a calendar-based system built on the ten stems, twelve branches and five elements.
- Is Saju the same as BaZi?
- Saju and BaZi are the same Four Pillars system. Saju is the Korean name and BaZi (八字) is the Chinese name. Given the same birth moment in true solar time, both produce the same eight characters. Korean and Chinese readers differ in some interpretation conventions and in how birth time is corrected.
- Can Saju be calculated without a birth time?
- Yes, with a loss. Without a birth time the year, month and day pillars can still be built, but the hour pillar is missing and the ten-year luck cycles cannot be timed as precisely. Most readers work with a three-pillar chart in that case and say so.
- Is Saju accurate?
- Saju is not a tested science. Saju is an interpretive system with a long tradition. What can be checked is the calculation: the four pillars for a given birth moment are a deterministic calendar result, and two correctly built charts for the same person must match character for character. 60Gapja publishes the corrections behind every pillar so that the calculation can be verified.