Korean Saju Calculator (사주 · Four Pillars)

What is saju?

Saju (사주, 四柱) means "four pillars." Its full name, saju palja (사주팔자, 四柱八字), means "four pillars, eight characters": the year, month, day and hour of your birth, each written as one Heavenly Stem above one Earthly Branch. It is the Korean name for the same chart known in Chinese as BaZi, built on the same calendar, the same solar terms and the same rules. Korean readers use Korean names for each part, and often describe themselves by their day pillar.

The calculator above draws the chart and explains its parts. Like any saju reading, the chart is a framework for reflection, not a prediction of events.

Why Korean birth times need correcting

Korea Standard Time is set for 135° east, a line that runs through Japan. Seoul sits at 126.98° east, so the sun there is about 32 minutes behind the clock; in Busan, at 129.03° east, about 24 minutes. Saju reads the Day and Hour pillars by the sun's time, so the clock time has to move back. The sun also runs a little fast or slow during the year (the equation of time), which adds between −14 and +16 minutes.

Korean clocks have also changed several times. We apply the rule that was in force on your birth date and place:

A common shortcut in Korean saju is to take 30 minutes off the clock, so the Zi hour runs from 23:30 to 01:29. That is close for most births in Seoul after 1961, but it goes wrong in three cases:

• Summer time. The clock was an extra hour ahead. Born in Seoul at 1:40 pm on May 20, 1988, your solar time was 12:11 and your hour pillar is 壬午 (임오). Taking off only 30 minutes gives 13:10 and a different hour pillar, 癸未 (계미).
• 1954 to 1961. The clock was already set to UTC+8:30, so taking off another 30 minutes moves the time too far. At 7:20 am on March 1, 1958 in Seoul, the solar time was 07:04, still in the 甲辰 hour; the shortcut gives 06:50 and the 癸卯 hour.
• Cities far from Seoul. At 11:35 am on July 15, 1995, the solar time was 10:57 in Seoul (乙巳 hour) but 11:05 in Busan (丙午 hour). One fixed number can't be right for both.

This calculator uses your birth city's longitude, the equation of time for your birth date and the clock rules in force at the time. You can switch true solar time off under the chart to see the clock-time version. How we calculate and test it.

Your ilju: the day pillar

Koreans often talk about their ilju (일주), the day pillar. "I'm a gyeongin ilju" means the day pillar is 庚寅 (경인). The top character of the day pillar, the ilgan (일간), is your Day Master: the character that represents you, and the one every other character in the chart is read against. There are 10 day stems and 60 day pillars; your result shows yours in Korean, romanized and in Chinese characters.

Read what each of the ten stems stands for on the Day Master pages.

Saju and BaZi: same chart, different words

The ten stems in Korean are 갑 을 병 정 무 기 경 신 임 계, and the twelve branches are 자 축 인 묘 진 사 오 미 신 유 술 해. Korean saju usually calls the Seven Killings star (七杀) 편관 (pyeongwan); the other Ten Gods have the same names in both traditions.

The Zi hour: 정자시 or 야자시?

The Zi hour runs from 23:00 to 01:00 by solar time, across midnight, and saju readers in Korea disagree about when the new day begins:

• 정자시 (jeongjasi): the new day starts at 23:00. Born at 23:30 solar time, you take the next day's pillar.
• 야자시 / 조자시 (yajasi / jojasi): the day changes at midnight. 23:00–23:59 is the night Zi hour: it keeps the same day pillar, and its hour pillar takes the next day's stem.

We start the new day at 23:00 by default, the same as our BaZi calculator. If your solar birth time falls between 23:00 and midnight, we show both versions, and you can switch the rule under the chart.

How to read your saju chart

1. Find your ilgan. The top character of the day pillar is your Day Master. The chart labels it "You".
2. Read the Ten Gods. The labels above the other stems (in Korean, the 십신 row) name how each one relates to your Day Master, such as Direct Officer (정관, structure and responsibility) or Eating God (식신, creativity).
3. Look at the month. The month pillar places you in a season, which classical texts use to judge how strongly your Day Master is supported.
4. Check the Five Elements. Which of Wood, Fire, Earth, Metal and Water appear often, and which are rare? A count shows emphasis, not good or bad.
5. Read your Daeun as phases. Each ten-year Luck Pillar brings a new stem and branch that highlight different themes.

The guide reads your own chart for you in plain English: work, money, love, your current decade and the next three years. It is built from the same chart and uses the English names shown here. See what's in the guide