Four Pillars
Your birth year, month, day and hour, each written as a pair of characters.
Saju means “four pillars”. Each pillar is a Heavenly Stem on top and an Earthly Branch below, giving eight characters in total (BaZi, 八字).
Learn the language of Saju
A plain-English glossary of every term you’ll see in your chart.
Heavenly Stems (天干)
Ten characters combining an element with Yin or Yang.
Jia/Gap 甲 (Yang Wood), Yi/Eul 乙 (Yin Wood), Bing/Byeong 丙 (Yang Fire), Ding/Jeong 丁 (Yin Fire), Wu/Mu 戊 (Yang Earth), Ji/Gi 己 (Yin Earth), Geng/Gyeong 庚 (Yang Metal), Xin/Sin 辛 (Yin Metal), Ren/Im 壬 (Yang Water), Gui/Gye 癸 (Yin Water). Stems are the visible, outward energy of a pillar.
Earthly Branches (地支)
Twelve characters linked to the zodiac animals, months and hours.
Rat 子, Ox 丑, Tiger 寅, Rabbit 卯, Dragon 辰, Snake 巳, Horse 午, Goat 未, Monkey 申, Rooster 酉, Dog 戌, Pig 亥. Branches are the deeper, seasonal ground of a pillar.
Day Master (日干)
The stem of your Day Pillar — the element that represents you.
Everything else in the chart is read in relation to the Day Master. It’s the single most important character in Saju.
Five Elements (五行)
Wood, Fire, Earth, Metal and Water — five phases of energy.
Elements feed each other (Wood → Fire → Earth → Metal → Water → Wood) and control each other (Wood → Earth → Water → Fire → Metal → Wood). Balance between them is a central theme.
Yin and Yang
Complementary energies: Yang is active and outward, Yin is receptive and inward.
Every stem and branch is either Yin or Yang. Neither is better — a mix is considered healthy.
Ten Gods (十神)
Ten roles each character plays relative to your Day Master.
Friend & Rob Wealth (same element: peers, independence), Eating God & Hurting Officer (what you produce: expression, creativity), Indirect & Direct Wealth (what you control: resources, effort), Seven Killings & Direct Officer (what controls you: discipline, pressure, status), Indirect & Direct Resource (what supports you: learning, care).
12 Life Stages (十二運星)
How strong your Day Master feels in each branch, like a life cycle.
Growth, Bath, Crown & Belt, Coming of Age, Peak, Decline, Sickness, Death, Tomb, Extinction, Conception, Nurture — a metaphor for rising and falling energy, not literal events.
Luck Pillars (大運)
Ten-year chapters of life, each with its own pillar.
They start a few years after birth and move forwards or backwards from your Month Pillar. Starting age = days to the nearest solar term ÷ 3.
Annual Pillars (歲運)
The pillar of each calendar year.
Each Saju year begins at Start of Spring (around 4 February), not 1 January or Lunar New Year.
Solar Terms (節氣)
24 points of the sun’s yearly path; 12 of them (Jie) start each Saju month.
Because Saju months follow the sun, they begin around the 4th–8th of each Gregorian month. We compare these to your birth as exact moments in time.
True Solar Time
Clock time adjusted to where the sun actually was at your birthplace.
Time zones are wide, so local noon rarely matches the sun. We correct for longitude (4 minutes per degree), daylight saving and the equation of time (Earth’s elliptical orbit).
Day Master strength
Whether your core element is strongly or lightly supported in the chart.
We look at the season of birth, roots in the branches and supporting stems. It’s a starting point for balance, not a judgement.
Symbolic Stars (神煞)
Traditional ‘stars’ found from your Day or Year pillar and marked on the branches where they fall.
We show seven widely used stars: Nobleman (天乙貴人), Peach Blossom (桃花), Travelling Horse (驛馬), Canopy (華蓋), Goat Blade (羊刃), Kui Gang (魁罡) and Void (空亡). Schools use different tables; ours follow common Korean practice. They add colour to a reading but never outweigh the elements.
Combinations & clashes (合沖刑破害)
How the characters of different pillars attract, merge or collide.
Stems can combine (天干合). Branches can form Six Harmonies (六合), Three Harmonies (三合), Directional combinations (方合), or clash (沖), punish (刑), destroy (破) and harm (害) each other. Interactions with your Luck and Annual Pillars show which natal areas a period stirs up.
Useful Element (用神)
The element that best brings your chart into balance.
Classical methods weigh season, strength, climate and combinations. We use a simplified, transparent version based on Day Master strength alone, and translate the result into colours, directions, seasons and activities.
Monthly Pillars (月運)
The pillar of each solar month in a given year.
Each month starts at one of the 12 Jie solar terms. Month stems follow the Five Tiger rule from the year stem, so the same branch gets a different stem each year.
Rat Hour (子時)
23:00–01:00, the first of the twelve two-hour periods.
Traditionally the new day starts at 23:00. Some schools split it into Late Rat (23–24) and Early Rat (0–1) and change the day at midnight.