Saju calculator · Korean Four Pillars · free
Enter your date, time and place of birth to see your Saju (사주): the year, month, day and hour pillars with their Heavenly Stems (cheongan) and Earthly Branches (jiji), your Day Master (ilgan), the hidden stems and the Ten Gods (sipseong), with the Korean names beside the Chinese ones. Calculated from the solar terms, without an account and without AI.
Saju is the Korean reading of the Four Pillars, the method known in China as BaZi. The year pillar changes at the start of spring — Ipchun (입춘), Li Chun in Chinese — around 4 February, the month pillars at the solar terms, the day pillars follow an unbroken cycle of sixty days, and the hour pillars divide the day into twelve two-hour periods. AstroSensus uses one engine for all three traditions, so the pillars here are exactly those of the BaZi calculator; only the names change.
The time correction is where Korean practice often differs. Korean Standard Time is reckoned from 135° East, while Seoul lies near 127° East, so many Saju apps read the birth time about 30 minutes earlier. Our option “solar time” does this from the longitude of the birthplace and adds the equation of time; by default the official clock is used, and the result always says which rule it used. South Korea’s historical time zones (UTC+8:30 from 1954 to 1961) and its summer time, including 1987 and 1988, are applied automatically.
Strength of the Day Master, the useful element (용신 yongsin) and the ten-year luck cycles (대운 daeun) are not shown yet: schools judge them differently, and we would rather show nothing than one school’s verdict without saying so.
The same eight characters, read in Korean. The calculator shows both names on every sign.
| Concept | Chinese (BaZi) | Korean (Saju) |
|---|---|---|
| Four Pillars (eight characters) | 八字 bāzì | 사주팔자 saju palja |
| Day Master | 日主 rìzhǔ | 일간 ilgan |
| Heavenly Stems | 天干 tiāngān | 천간 cheongan |
| Earthly Branches | 地支 dìzhī | 지지 jiji |
| Ten Gods | 十神 shíshén | 십성 sipseong |
| Hidden stems | 藏干 cánggān | 지장간 jijanggan |
| Five phases | 五行 wǔxíng | 오행 ohaeng |
| Year pillar | 年柱 niánzhù | 연주 yeonju |
| Month pillar | 月柱 yuèzhù | 월주 wolju |
| Day pillar | 日柱 rìzhù | 일주 ilju |
| Hour pillar | 時柱 shízhù | 시주 siju |
Year, month, day and hour — each Heavenly Stem (천간) and Earthly Branch (지지) in Chinese characters, in Hangul with romanization, and in plain words.
The stem of the day pillar, the point the whole chart is read from, with the image the tradition gives it.
The stems hidden in each branch and how every stem relates to your Day Master, under their Korean and Chinese names.
How many signs of Wood, Fire, Earth, Metal and Water the chart holds, and which pillars combine or clash.
Want your Western birth chart too — planets, houses and aspects? Open the free birth chart
Korea and Japan read the same Four Pillars under their own names. The pillars are calculated the same way; only the names differ.
Saju (사주, “four pillars”), in full Saju Palja (사주팔자, “four pillars, eight characters”), is the Korean name for the Four Pillars reading of the moment of birth. Each pillar — year, month, day and hour — has a Heavenly Stem and an Earthly Branch, eight characters in all. It is a traditional symbolic system: it describes how a tradition reads a chart, not proven facts about a person.
The calculation is the same: the same solar terms, the same sixty-day cycle and the same eight characters. Korean practice reads them in Korean — the Day Master is ilgan (일간), the stems are cheongan (천간), the branches jiji (지지) and the Ten Gods sipseong (십성). This calculator shows both names side by side, so a Saju chart and a BaZi chart of the same birth can be compared directly.
Korean Standard Time is counted from 135° East, but Seoul lies near 127° East, so the Sun stands highest over Seoul about 32 minutes after noon on the clock. Many Korean apps therefore move the birth time back by about 30 minutes before reading the hour pillar. Here this is the “solar time” option: it uses the longitude of the birthplace and also the equation of time, which adds up to about 16 minutes more or less depending on the season. Without it the calculator reads the official clock.
Yes. The time-zone history of the birthplace is applied automatically: South Korea used UTC+8:30 from 1954 to 1961, had summer time in several years between 1948 and 1960, and again in 1987 and 1988. Enter the time as it was on the clock; the calculator works out the moment of birth from it.
Then the calculator shows three pillars — year, month and day — and leaves the hour pillar (siju) empty instead of guessing it. The hour pillar changes every two hours.
Not in our database. It stays in your browser session for up to two hours and is deleted when you press “Forget my data”. Only if you create an account does it become the first person in that account.