Saju, Five Elements & Chinese Zodiac Basics Explained Simply

Last updated: 2026-06-25

⚠️ This guide explains the basic concepts of saju; saju and fortune interpretations are for entertainment only.

What is saju (the Four Pillars)?

'Saju' (四柱) literally means 'four pillars'. The four pillars are your birth year, month, day, and hour. Each pillar consists of one heavenly stem on top and one earthly branch below, and since there are four pillars, there are eight characters in all. That's why it is also called sajupalja (四柱八字), emphasizing the 'eight characters'. Saju and sajupalja essentially mean the same thing.

For example, someone born around midday on January 1, 2000 has a year pillar of Gyeongjin (庚辰) and a day pillar of Muo (戊午), with two characters per pillar. Laying out these eight characters and reading the structure of energy within them is the starting point of traditional saju study (命理學, myeongnihak).

10 heavenly stems and 12 earthly branches

The two axes of the stem-branch are the heavenly stems and the earthly branches. The stems are the ten characters Gap (甲), Eul (乙), Byeong (丙), Jeong (丁), Mu (戊), Gi (己), Gyeong (庚), Sin (辛), Im (壬), Gye (癸), and the branches are the twelve characters Ja (子), Chuk (丑), In (寅), Myo (卯), Jin (辰), Sa (巳), O (午), Mi (未), Sin (申), Yu (酉), Sul (戌), Hae (亥). Pairing stems and branches one by one in order gives combinations like Gapja (甲子), Eulchuk (乙丑), and the least common multiple of 10 and 12 — 60 combinations — completes one cycle. This is the sexagenary cycle, which is also why a 60th birthday (hwangap) is celebrated.

The year pillar is set by your birth year. By formula, the stem is the (year−4)%10-th character and the branch is the (year−4)%12-th. The day pillar cycles through the sexagenary cycle one per day, so we convert the date into a unified day count, the Julian Day Number (JDN), and take the remainder modulo 60. FortuneMoa's free saju tool computes the 8 characters this way.

The Five Elements: Wood, Fire, Earth, Metal, Water

The key to reading saju is the Five Elements (五行, ohaeng). They are the five energies that make up nature: Wood (木), Fire (火), Earth (土), Metal (金), Water (水). Every stem and branch belongs to one of these five energies. Gap/Eul are Wood, Byeong/Jeong are Fire, Mu/Gi are Earth, Gyeong/Sin are Metal, Im/Gye are Water; among the branches, In/Myo are Wood, Sa/O are Fire, Sin/Yu are Metal, Ja/Hae are Water, and Chuk/Jin/Mi/Sul are Earth.

The Five Elements cycle through mutually supportive generation (相生) and mutually restraining control (相剋) relationships. Generation runs Wood→Fire (wood feeds fire), Fire→Earth, Earth→Metal, Metal→Water, Water→Wood; control runs Wood→Earth (wood breaks soil), Earth→Water, Water→Fire, Fire→Metal, Metal→Wood. This endless turning of the five energies is the idea of the Five Elements, applied to nature and human fortune by analogy.

By counting how many of each Five Element appear among the saju 8 characters, you can see which way a person's energy leans. When an element is excessive or entirely absent, a common approach is to interpret toward supplementing the lacking energy. This, however, is a traditional perspective and has no scientific basis.

The 12 branches and the Chinese zodiac

What we commonly call your 'zodiac animal' is the animal attached to the year branch — the earthly branch of your birth year. Ja is the Rat, Chuk the Ox, In the Tiger, Myo the Rabbit, Jin the Dragon, Sa the Snake, O the Horse, Mi the Goat, Sin the Monkey, Yu the Rooster, Sul the Dog, and Hae the Pig. So someone born in 2000 (the Gyeongjin year) is a Dragon, and someone born in 2026 (the Byeong-O year) is a Horse.

Branches also form special relationships with one another: the trine (三合) where three branches unite into one energy, the six-harmony (六合) where two pair up, and the clash (沖) where opposites collide. Zodiac compatibility uses exactly these branch relationships. If two people's animals form a trine or six-harmony they are seen as a good match, and a clash is seen as a dynamic relationship. To try it yourself, pick two animals at Zodiac Compatibility.

The day master: the character that symbolizes 'you'

Of the saju 8 characters, the most important is the day master (日干, ilgan). The day master is the heavenly stem of your birth day, and it represents 'you yourself' in saju. The other seven characters are all interpreted relative to the day master — which energies they add to or take away from it. For example, someone whose day master is Gap (Wood) is read as upright and upward-reaching like a tree, while someone whose day master is Im (Water) is read as flexible and wise like water.

The lunar calendar, solar terms, and a caution

The standard for saju is to set the stem-branch from the solar (Gregorian) date. If you only know your lunar birthday, you must convert it to solar for accuracy. Also, professional saju divides the month by solar terms (like Ipchun and Gyeongchip) rather than the calendar month. FortuneMoa's free saju computes the year, day, and hour pillars accurately by the standard method, but the month pillar uses a simplified, for-fun approximation of the solar month without solar terms. So keep in mind it may differ from a precise professional saju consultation.

Wrapping up

So far we've covered the most fundamental concepts of saju: the four pillars (year, month, day, hour), the 10 stems and 12 branches, the sexagenary cycle, the Five Elements (Wood, Fire, Earth, Metal, Water) with generation and control, and the 12 zodiac animals and the day master. Even this much makes it far easier to understand what your saju 8 characters mean and why zodiac compatibility considers the trine and six-harmony. Now go check your own 8 characters and Five Elements distribution with free saju, and enjoy the 2026 Chinese zodiac forecast too. Once more: all saju and fortune readings are for entertainment only and should not be the basis for important decisions.

Last updated: 2026-06-25