The Four Pillars: Year, Month, Day and Hour

Year pillar (연주): the year you were born

The pillar of the year you were born. It stands for ancestors and childhood. The lower character of the year pillar is what we call the zodiac animal (띠). In saju the year changes at Ipchun (입춘, the Start of Spring, around 4 February in the solar calendar), not on 1 January or on Seollal (Lunar New Year). So someone born in January 2001 is not a Snake of 2001 but a Dragon (庚辰) of 2000.

Month pillar (월주): the month you were born

The pillar of the month you were born. It stands for parents and the social environment. The month also changes not on the first day of the lunar month but at twelve solar terms such as Ipchun (입춘), Gyeongchip (경칩) and Cheongmyeong (청명). The lower character of the month pillar (the month branch, 월지) tells the season of birth, so it carries the most weight when judging whether the Day Master's energy is strong or weak.

Day pillar (일주): the day you were born

The pillar of the day you were born (two characters, upper and lower). It is the place for you and for your spouse. The upper character, the Day Master (일간), stands for "you" in the whole chart, and the lower character, the day branch (일지), is taken as the spouse's place. This pillar is the starting point for reading a saju.

Hour pillar (시주): the hour you were born

The pillar of the hour you were born. It stands for children and later life. The day is divided into twelve slots of two hours each. If the hour of birth is not known, the chart is read without the hour pillar, with six characters, and the reading becomes less detailed in proportion to the characters lost. In that case Halmeoni also avoids saying anything that relies on the hour pillar.

Adjusting the hour of birth

A saju is read not by clock time but by time based on the sun at the place of birth. Korea Standard Time is set to 135°E, a longitude on the Japan side, so the clock runs ahead of the real sun by about 32 minutes in Seoul and about 24 minutes in Busan. The time is therefore corrected by the longitude of the city of birth, which is called the longitude correction (경도 보정). This is also why Halmeoni asks where you were born.

Korea used daylight saving time during the summers of 1948–1951, 1955–1960 and 1987–1988. If you were born in those periods, the clock had been set one hour ahead, so that is corrected as well.

11 pm to 1 am (the Ja hour, 자시)

The Ja hour (자시) straddles the change of date, so there are two ways of handling it. One counts it as the next day already from 23:00; the other keeps it as the same day until midnight and only reads the hour character as 子 (the approach that separates the Night Ja hour 야자시 from the Early Ja hour 조자시). By default Halmeoni calculates with the day changing at midnight. If you were born in this hour, the day pillar may come out differently from other manseryeok.