Saju in One Place: Heavenly Stems, Earthly Branches, the Five Phases, Luck Cycles, Void and Auxiliary Stars, the Comparison with Astrology — and the Limits

Saju is eight characters on a calendar

Saju (the Four Pillars) records the year, month, day and hour of birth as four pillars of two characters each — eight characters in all. Each pillar pairs one of the ten Heavenly Stems with one of the twelve Earthly Branches; there are sixty such pairs, known as the sexagenary cycle. This cycle has been used to count days in China for over three thousand years.

The discipline that links these characters to personality and fortune is called myeongri (Chinese mingli). Classics such as Yuanhai Ziping, which systematised the method associated with Xu Ziping around the Song dynasty, and Ditian Sui underpin interpretation today (Smith, 1991; Ho, 2003).

Heavenly Stems and Earthly Branches

Group	Characters	Role
10 Stems	Gap, Eul, Byeong, Jeong, Mu, Gi, Gyeong, Sin, Im, Gye	Visible energies
12 Branches	Ja, Chuk, In, Myo, Jin, Sa, O, Mi, Sin, Yu, Sul, Hae	Season, time and earth energies; the 12 zodiac animals

The twelve branches pair with the twelve zodiac animals — rat, ox, tiger, rabbit, dragon, snake, horse, goat, monkey, rooster, dog and pig. Personality readings of the animals are symbols added by folk tradition.

Worth knowing: in saju, the year begins not at Lunar New Year but at Ipchun, the “beginning of spring” (around 4 February), and months change at the solar terms rather than at each new moon. So people born in January or early February may have a different animal than they expect.

The five phases: wood, fire, earth, metal, water

Each stem and branch belongs to one of the five phases. They relate through a generating cycle (wood→fire→earth→metal→water→wood) and a controlling cycle (wood→earth→water→fire→metal→wood). Interpretation usually takes the stem of the birth day (the day master) as “the self” and looks at the balance of phases with the other characters.

Ten-year and yearly cycles

• Daeun (ten-year luck cycles): a sequence starting from the month pillar that changes roughly every ten years. The starting age is calculated from the number of days between the birthday and the next (or previous) solar term.
• Seun (yearly luck): each year’s own sexagenary pair. 2026 is a byeong-o (fire horse) year.

Interpretation looks at which phases are added when the ten-year and yearly cycles overlap with the natal chart.

Void and auxiliary stars

• Void (gongmang): because there are ten stems and twelve branches, grouping the sixty pairs into sets of ten always leaves two branches unpaired. These two unpaired branches are called the void and read as “emptiness.” Mathematically, it is a natural result of two cycles of different lengths.
• Auxiliary stars (sinsal): names such as the “travelling horse” or “peach blossom” attached to particular character combinations. There are very many, schools differ on which to use and how to read them, and many were added later. Be wary of readings that judge a whole life by one or two of them.

How it differs from Western astrology

	Saju	Western astrology
Basis	The sexagenary calendar (Ipchun, solar terms)	Actual positions of celestial bodies (planets, zodiac)
Information needed	Year, month, day, hour	Year, month, day, hour + birthplace
Core elements	Balance of the five phases	Planets, signs, houses, aspects
Time cycles	Ten-year and yearly cycles	Transits and returns

The biggest difference is that saju is computed from a calendar system rather than from direct observation of the sky.

The trend of combining saju and MBTI

Much content overlays saju and MBTI to read “your evolving personality.” Both can be useful as languages for self-reflection, but MBTI has long been criticised because people fairly often get a different type when they retake it (Pittenger, 2005). Stacking two uncertain systems does not make either more accurate.

The limits of the evidence, and how to use it

There has been no controlled research confirming that saju predicts personality, career aptitude or the future. In double-blind tests of astrology, a comparable system, predictions did no better than chance (Carlson, 1985).

So saju is most useful as a question rather than an answer. Instead of taking “my chart lacks fire” as destiny, use it as a prompt: “What passion or activity am I missing lately?” Make important decisions about careers, health or money on facts and professional advice.

In OIYO’s saju calculator you can see your eight characters and phase balance, and the sexagenary cycle page explains each pair.

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References

• Yuanhai Ziping (淵海子平), Song-era compilation in the Xu Ziping tradition.
• Ditian Sui (滴天髓).
• Smith, R. J. (1991). Fortune-tellers and Philosophers: Divination in Traditional Chinese Society. Westview Press.
• Ho, P. Y. (2003). Chinese Mathematical Astrology: Reaching Out to the Stars. RoutledgeCurzon.
• Pittenger, D. J. (2005). Cautionary comments regarding the Myers-Briggs Type Indicator. Consulting Psychology Journal: Practice and Research, 57(3), 210–221.
• Carlson, S. (1985). A double-blind test of astrology. Nature, 318(6045), 419–425.