What Is Korean Saju?
Saju (사주, literally “four pillars”) is the Korean practice of reading a birth chart cast from your year, month, day, and hour of birth. It shares its framework — the four pillars of destiny — with Chinese BaZi, but it is read through a distinctly Korean tradition that puts the day master and relationship compatibility first.
Saju and BaZi: one framework, two traditions
A saju chart and a BaZi chart are built the same way: four pillars — year, month, day, hour — each written as one of the ten heavenly stems and twelve earthly branches, then read through the five elements. Calculated correctly, the chart itself comes out identical either way.
What differs is the reading culture. Chinese BaZi developed schools centered on structure, wealth, and career; Korean saju kept fortune reading close to everyday life and made relationship compatibility its signature question.
What makes the Korean reading different
The day master comes first. Korean readers anchor the whole chart on the day stem — who you are at the core — and read every other pillar in relation to it.
Compatibility is a discipline of its own. Gunghap (궁합), the practice of matching two charts before marriage, has been part of Korean life for centuries. It scores how two people's five elements support or clash, with the reasons attached — not a vague yes or no.
And it is ordinary, not occult. In Seoul, saju cafes sit between coffee shops; people in their twenties and thirties drop in with friends. Getting your chart read is closer to a life checkup than a séance.
Why two calculators can give you different pillars
In the four pillars system, the year and month do not change on January 1st or on the first of the month. They change at solar-term instants — the moments the sun crosses fixed points on the ecliptic, such as the start of spring (ipchun, 立春). A calculator that handles those instants loosely shifts a pillar for anyone born near a boundary — which means a different chart entirely.
Our free calculator resolves solar-term instants from astronomical data, not from a language model, and prints the exact boundary time and timezone conversion it used on the result screen. The same birth details always produce the same chart.
What's in a saju chart
Four pillars, eight characters: a stem and a branch for each of year, month, day, and hour. From these come your day master, the balance of the five elements — wood, fire, earth, metal, water — and 518,400 possible combinations. That chart is the raw material every reading is built from.
Cast your chart free
Enter your birth date, time, and place; the calculator returns your four pillars, day master, and element balance free, with no account. The written reading is paid — the chart and its calculation basis are free.
Frequently asked questions
- What is saju?
- Saju is Korean four pillars of destiny reading: a birth chart cast from the year, month, day, and hour of birth, written in heavenly stems and earthly branches and read through the five elements.
- Is saju the same as BaZi?
- The chart-building framework is the same, so a correctly calculated saju chart and BaZi chart are identical. The traditions differ in how they read it: Korean saju anchors on the day master and treats compatibility (gunghap) as a central discipline.
- Why do different calculators give me different charts?
- Year and month pillars change at solar-term instants, not calendar dates. Calculators that approximate those instants — or mishandle timezones — shift the pillars for anyone born near a boundary. Ours resolves the instants from astronomical data and shows the boundary time it used.
- Do I need my exact birth time?
- You can cast a chart without it — the calculator supports an unknown-time mode using three pillars. With the time, you also get the hour pillar and a more precise reading.
- Is the calculator actually free?
- Yes. The chart — four pillars, day master, element balance — and its calculation basis are free with no account. Only the written interpretation is paid.