How to Read Your Four Pillars (Saju) Chart
Your Saju — also called the Four Pillars of Destiny, or BaZi in Chinese — is a snapshot of the energy present at the exact moment you were born, written in the old language of ten Heavenly Stems and twelve Earthly Branches. A manse (만세력) is the traditional perpetual calendar used to convert any birth date and time into those four pillars. This free calculator does it for you in seconds.
The Four Pillars, one by one
Year Pillar — your roots: ancestry, early environment, and the broad generation you belong to.
Month Pillar — your formative years, your career engine, and your social self. It is the single most important pillar for judging the overall structure of a chart, because it carries the season you were born into.
Day Pillar — this is you. The upper character is your Day Master (your core self), and the lower character is your "spouse palace," which speaks to partnership.
Hour Pillar — your later years, your children, and your private inner world.
Your Day Master: the anchor of the whole chart
The Heavenly Stem sitting on top of your Day Pillar is your Day Master — the "you" that everything else in the chart is read against. There are ten of them: Yin and Yang versions of Wood, Fire, Earth, Metal, and Water. Knowing yours is the first real step into Saju, because it frames your personality, your strengths, and the relationships in your chart.
The Five Elements and their balance
Every stem and branch carries one of the five elements — Wood, Fire, Earth, Metal, Water. The balance between them (and, just as importantly, what is missing or excessive) shapes temperament, health tendencies, and the flow of fortune. The colored cells in your result show this balance at a glance.
The Ten Gods (십신): the relationships in your chart
Above each stem and branch, this manse now labels a Ten God (십신, sipsin). The Ten Gods are not extra characters — they are the relationship between your Day Master and every other element in the chart. Ask "what is this element to me?" and you get one of ten answers grouped into five pairs: does it share my nature (Companion / Rob Wealth), do I produce it (Output / Eating God), do I control it (Direct / Indirect Wealth), does it control me (Officer / Seven Killings), or does it produce me (Resource / Indirect Resource)?
This is the layer that turns raw stems into meaning. Wealth gods speak to money and — for some charts — partnership; Officer gods to career, discipline, and reputation; Output gods to expression, talent, and children; Resource gods to learning, support, and protection; Companion gods to peers, rivals, and independence. Seeing a Ten God sitting above each character is how a reader moves from "what are my pillars" to "what do they actually mean for my life."
Hidden Stems (지장간): what each branch conceals
Each Earthly Branch looks like a single character, but it secretly holds one to three Heavenly Stems inside it — the 지장간 (hidden stems), now listed beneath each branch in your result. They are the "sub-elements" quietly working underneath the visible chart.
Hidden stems are why two people with the same visible pillars can still read differently. The branch 寅 (Tiger), for example, conceals Wood, Fire, and Earth, and which of them is dominant depends on where in the solar-term month you were born. These concealed stems are the bridge between your four visible pillars and the deeper layers of 격국 (chart structure) and 용신 (the balancing element that a full analysis is built around).
Major Luck Cycles (대운): how your fortune unfolds over decades
Your four pillars are the fixed map; the 대운 (Major Luck Cycles) are how you travel across it. Every ten years a new stem-and-branch pillar governs the general climate of your life — a decade that leans toward career, or study, or relationships, depending on how it interacts with your natal chart. The timeline in your result lays these decades out in order, with the current one highlighted.
Two details decide the timeline. The starting age (대운수) is computed from how far your birth date sits from the nearest solar term. The direction — whether the cycles run forward or backward through the sixty stem-branch combinations — depends on the polarity (Yin/Yang) of your birth year together with your sex. That is exactly why the calculator asks for your sex: not to change the tone of any reading, but to decide which way your luck pillars turn.
Why your exact birth time matters
The Hour Pillar changes roughly every two hours, so a guessed time can change a quarter of your chart. Even more subtly, the Month Pillar is set by the 24 solar terms — not by the calendar month — so a birthday near a solar-term boundary can shift the whole reading. Enter your time as precisely as you can, and use the timezone and longitude options for the most accurate result.
Clock time vs. true solar time: the longitude correction
The time on your birth certificate is standard clock time, but Saju is calculated from true solar time — where the Sun actually was in the sky at your location. These two rarely match. Korea's standard time (UTC+9) is anchored to the 135°E meridian, yet most of the country sits near 127°E. Since every degree of longitude equals four minutes of solar time, Seoul runs roughly 32 minutes behind the clock: when your watch says 12:00, the true solar time is about 11:28.
That gap matters because the Hour Pillar changes on two-hour boundaries (23:00, 01:00, 03:00, and so on). A birth recorded at 23:10 standard time is really about 22:38 in true solar time — which moves it out of the early 자시 (Rat hour) back into 해시 (Pig hour), changing the entire Hour Pillar. The further your birthplace is from its timezone's central meridian, the larger the correction.
This is also why birthplace, not just the clock, matters: someone born in Japan (135°E) needs almost no correction, while births in western China or under a historical daylight-saving period (Korea used DST in several years between 1948 and 1988) need an extra adjustment. Use the timezone and longitude options above so the calculator works from your true solar time, not the raw clock reading.
What the 24 solar terms (절기) are
Long before clocks and calendars settled into their modern form, East Asian astronomy divided the year by the Sun's actual position. Picture the Sun's yearly path across the sky as a 360° circle, then slice it into 24 equal arcs of 15° each — every slice begins at a solar term (절기). The familiar markers — 입춘 (start of spring), 춘분 (spring equinox), 하지 (summer solstice), 추분 (autumn equinox), 동지 (winter solstice) — are all solar terms. Because they follow the Sun, they track the seasons far more faithfully than calendar months, which is exactly why farmers relied on them for planting and harvest.
The 24 terms alternate between two kinds: twelve "nodes" (절, 節) and twelve "mid-points" (중기, 中氣). For Saju, the twelve nodes are the ones that count — each node opens one of the twelve Saju "months." So the Saju year is not built from January through December at all; it runs from 입춘 to 경칩, 경칩 to 청명, and so on around the wheel.
Here is why it matters for your chart: your Month Pillar is decided by which solar-term month your birth falls into, not by the calendar month on your certificate. The month branch (월지) is fixed directly by the solar term, and the month stem (월간) follows from it by a set rule tied to your year stem. Get the solar term wrong and the entire Month Pillar — the single most important pillar for judging a chart's structure — comes out wrong.
Why the exact moment of a solar term matters
Because a solar term is the instant the Sun reaches an exact ecliptic longitude (입춘 at 315°, 경칩 at 345°, 청명 at 15°, and so on), the boundary between two Saju months is not a day but a precise minute — the moment of entry, 절입. That is why a good manse lists each term down to the hour and minute, and why a birth on the "same day" can fall in different months depending on the time.
A subtle point: the moment of solar-term entry is geocentric, so it is the same physical instant everywhere on Earth — it does not depend on your longitude. What the longitude correction from the previous section shifts is your birth time. Because the boundary is precise to the minute, that correction can decide which side of it you fall on. The term instant is fixed; your corrected birth instant is what slides across it.
This is most dramatic at 입춘, the year boundary in Saju — the Year Pillar and your zodiac animal change at 입춘, not at January 1st or Lunar New Year. Suppose 입춘 falls at 11:43 on February 4. A birth at 11:30 standard time keeps the previous year's pillars (and the previous animal sign); 11:50 takes the new ones. Apply Seoul's ~32-minute correction and a clock reading of 12:10 becomes 11:38 true solar — back before 입춘. For births near a boundary, the correction doesn't just nudge the Hour Pillar; it can flip the Month and even the Year Pillar.
How the lunar date is computed — and why Saju is not "lunar"
A lunar month follows the Moon's synodic cycle of about 29.53 days, so lunar months alternate between 29 and 30 days. Twelve of them total roughly 354 days — about 11 days short of the 365.24-day solar year. To keep the lunar calendar from drifting through the seasons, a leap month (윤달) is inserted about seven times every 19 years (the Metonic cycle), which works out to roughly once every two to three years.
Here is the part that trips people up: Saju does not run on the lunar calendar. The pillars — and the Month Pillar in particular — are set by the solar-term calendar described above, which tracks the Sun, not the Moon. Your 음력 생일 (lunar birthday) is a cultural date for traditional celebrations; it is not what determines your Month Pillar. Two people can share a lunar birthday and still have different month pillars if a solar-term boundary falls between them.
The lunar date this calculator shows is provided as a convenient cross-reference, so you can match your chart to a traditional lunar birthday. Just don't mistake that lunar date for the basis of the reading — the analysis itself is built on true solar time and the solar terms.
How to use this calculator
Enter your birth date and time above. The calculator instantly returns all four pillars with five-element colors, identifies your Day Master, and shows the matching lunar date and any solar term — no sign-up required.