What is Korean Saju? The four pillars, explained

Saju (사주, ‘four pillars’) is the Korean name for the four-pillars system that shares its roots with Chinese Bazi. A chart records the year, month, day and hour of a birth. Each pillar has two characters: a heavenly stem and an earthly branch. Four pairs make eight characters. Those characters give a reading its starting point. The name describes the chart's structure, rather than a separate animal calendar.

Your zodiac animal is your birth year. Saju reads the day you were born. It also keeps the other pillars in view. Two people can share a year animal and have different day pillars, so a year animal alone does not describe the whole chart.

There are ten heavenly stems and twelve earthly branches. They move together through a repeating sequence of sixty pairs. A branch has an animal association; a stem belongs to an element. These are two parts of the same pillar, rather than two competing results. Reading only the animal leaves out the stem, just as reading only the stem leaves out the branch.

The same pair can appear in different positions in a chart. Its position matters to how the chart is read. Bornimal starts with the day pillar as an accessible name tag, then uses the wider chart for context. The name tag is a way into the characters, rather than a substitute for them.

Wood, fire, earth, metal and water are the five elements. They are symbolic categories used to discuss the characters and their relationships. They give a reading a vocabulary for tendencies. They do not measure what a person is made of, and an element label does not settle who that person will become.

The heavenly stem of the day pillar is called the day master. In a reading it stands for ‘you’: the reference point for considering the other characters. The day master is one character, while the day pillar is the complete stem-and-branch pair. Keeping that distinction makes the chart easier to follow. An animal name refers to the pair; it is not another name for the day master alone.

In Korea, colour-and-animal names traditionally name years, such as the Year of the Red Horse. Naming the sixty day pillars as animals is Bornimal's own interpretation. We apply a readable colour-and-animal label to each day pillar. That label is a presentation choice, and we say so because a traditional year name and our day name can sound alike.

The colour comes from the day's stem element: Blue for wood, Red for fire, Golden for earth, White for metal and Black for water. The animal comes from the earthly branch. The result names one of sixty pairs. It does not add another pillar to the chart or change the characters calculated from your birth details.

Bornimal describes tendencies for reflection. It does not predict events. A description can give you language for a familiar habit or a pattern you want to consider. You can disagree with it. The useful question is whether the description helps you notice something, rather than whether a label can explain every choice you make.

The calculation and the interpretation do different jobs. Your birth details determine the chart; the writing offers a way to think about it. Year and month follow exact solar terms. Day and hour follow true solar time, with the day changing at 23:00 solar time. If your birth time is unknown, the result contains three pillars. Start with the details you know.