Saju, written 사주 in Korean and 四柱 in Chinese characters, means "four pillars." It is the Korean name for a traditional East Asian way of describing a birth moment, known in Chinese as Bazi, or "eight characters." Saju translates the year, month, day, and hour of birth into symbols drawn from an old calendar system. This guide covers the building blocks: the ten Heavenly Stems, the twelve Earthly Branches, the sixty-pair cycle they form, and the five elements behind them.

Four pillars, eight characters

A Saju chart has four columns, one each for the year, month, day, and hour of birth. Each pillar holds two characters: a Heavenly Stem on top and an Earthly Branch below. Four pillars of two characters makes eight in total, which is why Koreans say saju palja (사주팔자), "four pillars, eight characters," when talking about someone's lot in life.

Many practitioners treat the stem of the day pillar, often called the day master, as the symbol for the person, and read the other seven characters in relation to it. Methods differ between schools, so no chart has a single official interpretation.

The ten Heavenly Stems

The stems, cheongan (천간) in Korean, run in a fixed order of ten. They come in pairs: each of the five elements appears twice, first in its yang form and then in its yin form. Yang is usually described as outward and active, yin as inward and receptive. Korean readings come first, with the Mandarin readings used in Orbit Oracle's English reading in parentheses.

Teachers often attach a nature image to each stem as a memory aid: 甲 as a tall tree and 乙 as a vine, 丙 as the sun and 丁 as a candle flame.

The twelve Earthly Branches

The branches, jiji (지지) in Korean, are the same twelve signs most people know from the animal zodiac. Each branch also carries an element and marks a two-hour block of the day, which is how the hour pillar is assigned.

Two small details prevent confusion. First, the stem 辛 and the branch 申 are both romanized as "Sin" in Korean, so the Chinese character is the reliable way to tell them apart. Second, the four earth branches, 辰, 未, 戌, and 丑, each sit at the end of a season, which is one reason earth is linked with transition.

The sixty-pair cycle

Stems and branches advance together one step at a time: 甲子 (Gapja), 乙丑 (Eulchuk), 丙寅 (Byeongin), and onward. With ten stems and twelve branches, the two sequences realign only after sixty steps, the smallest number both ten and twelve divide evenly. The cycle ends at 癸亥 (Gyehae) and then begins again at 甲子. Only half of the 120 conceivable stem and branch pairings ever occur, because a yang stem always lands on a yang branch and a yin stem on a yin branch.

The same sixty-step sequence labels years, months, days, and hours. Days run through it as an unbroken count, independent of weeks and months, that has been kept for well over two thousand years. Two familiar examples: 2024 was 甲辰 (Gapjin), widely called the blue dragon year, and 2026 is 丙午 (Byeong-o), the red horse year, since 丙 is fire and fire is associated with red. The return of a person's birth-year pair after sixty years is also why hwangap (환갑), the sixtieth birthday, is a traditional milestone in Korea.

The five elements and their two cycles

The five elements, ohaeng (오행) in Korean, are wood, fire, earth, metal, and water. They are better understood as phases of change than as physical substances. Each is paired with a season: wood with spring, fire with summer, metal with autumn, water with winter, and earth with the transitions between seasons, or in some systems with late summer.

Two cycles describe how the elements relate. In the generating cycle, each element feeds the next: wood feeds fire, fire leaves ash that becomes earth, earth holds the ore that becomes metal, metal gathers condensation that becomes water, and water nourishes wood. In the controlling cycle, each element restrains another: wood breaks up earth with its roots, earth dams water, water puts out fire, fire melts metal, and metal cuts wood.

Much of Saju interpretation is about balance among these relationships. A chart heavy in one element and light in another is usually described as having a tilt, not as good or bad. For reflection, the cycles suggest two questions: what is feeding you right now, and what is keeping you in check?

Why an accurate chart needs a solar calendar and a birth time

Many people assume Saju runs on the lunar calendar. In most modern practice, the pillars follow the solar terms instead: twenty-four points on the Sun's yearly path, about fifteen days apart. The year pillar changes at Ipchun (입춘), the start of spring, around February 4, not on January 1 or at Lunar New Year. Someone born in mid-January 2026, for example, still belongs to the previous year's pillar, 乙巳 (Eulsa). Month pillars also turn over on solar terms, which fall around the fourth to the eighth of each Gregorian month, so they rarely match calendar months neatly.

The hour pillar needs a birth time, and even a recorded time needs care. Korea's standard clock is set to longitude 135 degrees east, while Seoul sits near 127 degrees east, so local solar time in Seoul runs roughly thirty minutes behind the clock. Many practitioners adjust for this. Korea has also changed its official time offset and used daylight saving time in some past years, and schools disagree about how to treat births between 11 p.m. and midnight. Without a reliable birth time, a practitioner can only work with three pillars.

How Orbit Oracle's Saju Lite is different

Orbit Oracle's Saju Lite reading borrows this vocabulary but keeps it deliberately simple. It takes a year tone from your calendar birth year, a season signal from your birth month, and a two-hour time branch from the time you enter, then pairs those symbols with a three-card tarot draw. It does not calculate solar-term boundaries, adjust for local solar time, or build a full four-pillar chart, so a January or early February birthday may show a different year tone than a professional chart would. Saju Lite is an entertainment and self-reflection tool, not a full Four Pillars consultation, and it makes no predictions about health, money, relationships, or any fixed future.

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