Is Korean saju the same thing as Chinese astrology?
Comparisons · 6 min read · Updated 28 September 2026
In short
Yes. Korean saju and Chinese astrology are the same system under different names: same calendar, same method, same four parts. What differs is the vocabulary and, in one place that genuinely matters, the clock: Korea’s official time is set to a line that runs through Japan, so a Korean birth time sits about half an hour ahead of the sun and readings there correct for it. Everything else comes out identical.
One system, several names
The method spread out of China across the region and kept its structure everywhere it landed. In Korea it is 사주 or 사주팔자. In Japan it is 四柱推命, shichū suimei. In Vietnam it is Tứ Trụ. In English it appears as Bazi, Four Pillars, Four Pillars of Destiny, and occasionally Ziping, after the Song-dynasty figure associated with reading from the day master rather than the year.
These are not variants the way tropical and sidereal astrology are variants. Feed the same birth moment into a Korean 만세력 and a Chinese 排盤 and, time conventions aside, the eight characters come out identical, because both are reading the same astronomical calendar.
The vocabulary, side by side
Four pillars: 四柱 in both · 사주 saju
Heavenly stems: 天干 · 천간 cheongan
Earthly branches: 地支 · 지지 jiji
Day master: 日主 or 日元 · 일간 ilgan, the day stem
Five elements: 五行 · 오행 ohaeng
Ten Gods: 十神 · 십성 sipseong, or 육친 yukchin for the family readings
Luck pillars: 大運 · 대운 daeun
Perpetual calendar: 萬年曆 · 만세력 manseryeok
The one difference that changes the chart
Korea’s standard time is UTC+9, built on the 135th meridian east, which runs through Japan, not Korea. Seoul sits near 127 degrees east, about eight degrees west of that meridian, so Korean clock time runs roughly half an hour ahead of the sun. Much of Korean Saju practice handles this by subtracting about thirty minutes from the recorded birth time before reading the hour pillar.
The history makes it worse rather than better. Korea has not always used UTC+9: it kept UTC+8:30 from 1908 to 1912 and again from 1954 to 1961, which means the correct offset depends on the birth year and not only on the birthplace. A birth in 1958 and a birth in 1968 need different arithmetic.
This is why a Korean reader and a Chinese reader can produce different hour pillars for the same person and both be working correctly by their own convention. It is also why it is worth knowing which convention any tool you use has applied. A calculator that converts properly to true solar time from the birth place sidesteps the argument entirely, because it is reading the sun rather than a national standard.
Where the traditions actually diverge
Beyond the clock, the differences are of emphasis rather than mechanism. Popular Korean Saju leans heavily on the Ten Gods as relationship and family readings, and on 신살, the symbolic stars, which parts of contemporary Chinese practice treat as a secondary layer. Japanese 四柱推命 developed its own terminology and its own popular literature from the Meiji period onward. Within China itself the schools disagree with each other at least as much as they disagree with Korea.
The practical consequence for an English-speaking reader is reassuring: material written for Saju, for Bazi and for Shichū Suimei is all describing one thing, and learning the stems, branches and Ten Gods once gives you access to all of it. Search for both terms: the English writing on Saju and the English writing on Bazi cover different ground and rarely cite each other.
Common questions
Can I use a Bazi calculator for my Saju?
Yes, for the year, month and day pillars in almost every case. The exceptions are births within about half an hour of midnight or of a change of month, where the Korean clock correction can tip the day or month pillar. Check the hour pillar if you were born in Korea, since the two traditions handle Korean clock time differently. Also check whether the tool asked you for a birth place at all.
Is Saju the same as the Korean zodiac animal?
No, though they overlap. The animal, 띠, is the branch of the year pillar, one of the eight characters. Saju is the whole chart, and most of a reading is about the other seven.
Is Bazi related to Feng Shui?
They share a vocabulary (five elements, stems, branches) and practitioners often study both, but they answer different questions. Bazi reads a person from a birth moment; Feng Shui reads a space. Neither is derived from the other.
Which is older?
Neither, since they are the same tradition. The sexagenary cycle itself is attested in Shang-dynasty oracle bone inscriptions, and the day-master method that both use today took its familiar shape around the Song dynasty.
Build the chart once and read it either way
8 Signs converts your birth time to true solar time from the place you were born, so the hour pillar does not depend on which country's clock you grew up with. Free to start.
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