What is the Day Master in a saju chart?
The Day Master is the Heavenly Stem of the day pillar: the upper character of the pillar for the day you were born. In the example above (born March 15, 1995 at 14:30 in Seoul, female), the four pillars are 乙亥 for the year, 己卯 for the month, 乙巳 for the day and 癸未 for the hour. The day pillar is 乙巳, so the Day Master is 乙 (eul), which is Yin Wood.
Korean sources call this character ilgan (일간, 日干), "the day stem". Day Master is the usual name for it in English-language BaZi books, and this site uses both.
The Day Master block above the pillar table shows what the calculator says about the character: its Korean reading and element ("eul Yin Wood"), a traditional image with a short description ("the vine and the flower"), and a seasonal type name ("Spring Flower").
A saju chart has eight characters in four pillars, and each pillar has a Heavenly Stem on top and an Earthly Branch below. The Day Master is the one character that stands for the person the chart belongs to. The Encyclopedia of Korean Culture describes a saju reading as centered on the stem of the day pillar, which it calls gisin (己身), "one's own self".
The other seven characters are named by how they relate to the Day Master. In the pillar table above, the Day pillar column says "Day Master" in the top Ten god row. The Month pillar column says Pyeonjae (Indirect Wealth) in that row, and the Year pillar column says Bigyeon (Friend). Both names describe those stems as seen from 乙.
For that reason the Day Master is the first step in reading a saju chart in order, and the saju compatibility calculator compares the Day Masters of two people.
Why is the Day Master not your birth-year animal?
The zodiac animal (tti, 띠) that most people know comes from a different pillar and a different kind of character.
| Point of comparison | Day Master (ilgan) | Zodiac animal (tti) |
|---|---|---|
| Character it comes from | Heavenly Stem of the day pillar | Earthly Branch of the year pillar |
| Number of kinds | 10 | 12 |
| How often it changes | Every day | Once a year. In a saju chart the change comes at Ipchun (立春, the Beginning of Spring), around February 4 |
| In the example above | 乙 (eul), Yin Wood | 亥 (hae), Pig |
Everyone born in the same saju year has the same animal. Their Day Masters differ, because the day stem moves to the next of the ten stems every day. March 14, 1995 was a 甲 day, March 15 an 乙 day and March 16 a 丙 day.
The year pillar used to carry more weight. According to the Academy of Korean Studies' dictionary of the Annals of the Joseon Dynasty, readings before China's Song dynasty were based mainly on the year pillar, and the book known in Korea as Seo Japyeong (徐子平) changed the basis to the day stem. The same entry says that this doctrine became the mainstream of modern saju, and that the book was an examination text for selecting officials of the Gwansanggam, the Joseon court office that published the calendars.
The example chart shows how the two get mixed up. Its year stem is also 乙, but that 乙 belongs to the year pillar and is read as Bigyeon (Friend). Only the stem in the Day pillar column is the Day Master.
The day pillar has an animal of its own, taken from its branch. The example's day pillar 乙巳 is the Blue Snake, and its year pillar 乙亥 is the Blue Pig. The page on Korean zodiac color animals explains both names.
Which element is "my saju element"?
When a saju reading speaks of your element, it means the element of your Day Master, because the chart is read from that stem. Two other things are sometimes called by the same name, and each comes from different characters.
| What gets called "my element" | Where it comes from | In the example above |
|---|---|---|
| Element of the Day Master | Heavenly Stem of the day pillar | Yin Wood (乙) |
| Element of the birth year | Heavenly Stem of the year pillar, which also gives the color in names such as Blue Pig | Yin Wood (乙) |
| Most common element | The five elements (ohaeng) count over all eight characters | Wood, with 3 of the 8 |
In the example all three are Wood, which is a coincidence of this chart. A birth one day later, on March 16, 1995 at the same time and place, has the Day Master 丙 (Yang Fire) while its year stem is still 乙 (Yin Wood).
The ten Day Masters: element, yin-yang and traditional image
A Day Master is always one of the ten Heavenly Stems. The stems run in a fixed order in five pairs. Each pair shares one of the five elements, and within a pair the first stem is yang and the second is yin. The images and descriptions in this table are the ones the calculator shows in the Day Master block.
| Day Master | Korean reading | Element | Yin-yang | Traditional image | How the tradition describes it |
|---|---|---|---|---|---|
| 甲 | gap (갑) | Wood | Yang | The tall tree | Upright, principled and forward-moving. The same straightness is read as stubbornness. |
| 乙 | eul (을) | Wood | Yin | The vine and the flower | Gentle, flexible and good at adapting. Also read as quietly persistent. |
| 丙 | byeong (병) | Fire | Yang | The sun | Bright, open and generous. The same heat is read as impatience. |
| 丁 | jeong (정) | Fire | Yin | The candle flame | Warm, attentive and focused. Also read as sensitive, with feelings that run deep. |
| 戊 | mu (무) | Earth | Yang | The mountain | Steady, patient and dependable. The same weight is read as slowness to change. |
| 己 | gi (기) | Earth | Yin | The field | Practical, caring and good at helping things grow. Also read as cautious and inclined to worry. |
| 庚 | gyeong (경) | Metal | Yang | The iron sword | Direct, decisive and loyal. The same hardness is read as bluntness. |
| 辛 | sin (신) | Metal | Yin | The jewel | Precise, refined and sensitive to quality. Also read as proud and easily hurt by criticism. |
| 壬 | im (임) | Water | Yang | The ocean | Broad-minded, resourceful and always moving. The same flow is read as restlessness. |
| 癸 | gye (계) | Water | Yin | The rain | Quiet, perceptive and imaginative. Also read as changeable in mood. |
Two different characters are read "sin" in Korean: the stem 辛 (Yin Metal) and the Earthly Branch 申 (Monkey). Only 辛 can be a Day Master.
Most of these images go back to classical Chinese texts of the four-pillars tradition. Sanming Tonghui (三命通會), a compendium in use since the Ming dynasty, labels the ten stems in order as yang Wood, yin Wood, yang Fire and so on down to yin Water, and says for most of them what the stem is "in the sky" and "on the ground". Di Tian Sui (滴天髓) gives each stem a short verse.
| Day Master | Classical wording | Text |
|---|---|---|
| 甲 | "甲 Wood reaches the sky" (甲木參天) | Di Tian Sui |
| 乙 | "a vine that ties itself to 甲" (籐蘿繫甲) | Di Tian Sui |
| 丙 | "in the sky it is the sun and lightning" (在天為日為電) | Sanming Tonghui |
| 丁 | "on the ground it is lamp fire" (在地為燈火) | Sanming Tonghui |
| 戊 | "on the ground it is the mountain" (在地為山) | Sanming Tonghui |
| 庚 | "on the ground it is metal and iron" (在地為金鐵) | Sanming Tonghui |
| 壬 | "壬 Water is a vast sea" (壬水汪洋) | Di Tian Sui |
| 癸 | "in the sky it is rain and dew" (在天為雨露) | Sanming Tonghui |
The images are memory aids, and the old commentators treated them that way. The commentary printed with Di Tian Sui says that 辛 is yin Metal and that this "does not mean pearls and jade" (非珠玉之謂). The descriptions in the first table work the same way. They report what the tradition says about a stem, and the Day Master is one character out of eight.
What is the type name under the Day Master?
Under the description of the Day Master, the calculator prints a second name, which is "Spring Flower" in the example. It combines the season of the month branch with the Day Master. Four seasons and ten Day Masters give 40 types.
| Month branch | Season |
|---|---|
| 寅 (Tiger), 卯 (Rabbit), 辰 (Dragon) | Spring |
| 巳 (Snake), 午 (Horse), 未 (Sheep) | Summer |
| 申 (Monkey), 酉 (Rooster), 戌 (Dog) | Autumn |
| 亥 (Pig), 子 (Rat), 丑 (Ox) | Winter |
The example's month pillar is 己卯. Its branch 卯 belongs to spring and the Day Master is 乙, so the type is Spring Flower. An 乙 Day Master with the month branch 巳 is a Summer Vine. The 40 names are this site's own labels, a reminder that saju reads the same Day Master differently in each season. They are not terms from the classical texts.
What do strong and weak Day Masters mean?
Strength describes how much support the Day Master gets from the other seven characters. A character supports the Day Master when it has the same element or the element that produces it. For the Wood Day Master in the example, that means Wood and Water. Singang (신강, 身強) is the Korean word for a strong Day Master and sinyak (신약, 身弱) for a weak one. The two words describe balance, and neither is good or bad in itself.
The calculator makes three yes-or-no checks.
| Check | What it asks | In the example above |
|---|---|---|
| In season (deukryeong, 得令) | Does the month branch, which sets the season of birth, support the Day Master? | Yes. The month branch 卯 is Wood. |
| Rooted (deukji, 得地) | Does the day branch, which sits directly under the Day Master, support it? | No. The day branch 巳 is Fire. |
| Supported (deukse, 得勢) | Do the other stems and branches mostly help the Day Master? | Yes. |
It then rates the chart on seven levels. The rating combines the three checks with a score for the support found in each pillar, and the month pillar counts most.
| Level | Name on the result | What it means |
|---|---|---|
| 1 | Very weak | The Day Master gets very little support from the rest of the chart. |
| 2 | Weak (sinyak) | The Day Master has less support than pressure. |
| 3 | Slightly weak | The Day Master leans a little to the weak side. |
| 4 | Balanced | Support and pressure on the Day Master are close to even. |
| 5 | Slightly strong | The Day Master leans a little to the strong side. |
| 6 | Strong (singang) | The Day Master has more support than pressure. |
| 7 | Very strong | The Day Master is supported by almost the whole chart. |
The example is rated Slightly strong, level 5 of 7. The strength section appears in the complete result on the saju calculator home page. The guide to reading a saju chart shows where strength comes in the reading order and what follows from it.
How was the Day Master found before calculators?
Before software, finding a Day Master meant opening a manseryeok (만세력, 萬歲曆, "ten-thousand-year almanac") and reading off the sign of the birth day. According to the Encyclopedia of Korean Culture, the Gwansanggam published the Manseryeok in 1782 by royal command, with the calendar worked out for 100 years from 1777 and designed to be extended ten years at a time. It was first called Cheonseryeok (千歲曆, "thousand-year almanac") and was reissued as Manseryeok in 1904. Its contents include the sign of each year (taese, 太歲), of each month (wolgeon, 月建) and of each day (iljin, 日辰).
The encyclopedia's entry on saju explains how the almanac is used. The formal procedure for setting up four pillars is laborious, so people commonly look them up in the Manseryeok. The year and month printed there need care, because the saju year starts at Ipchun and the saju months start at the solar terms. The day pillar is copied exactly as printed, because the day sign has its own cycle and does not depend on the year or the solar terms.
That cycle has 60 steps, one for each day. The same day pillar comes back every 60 days, and the same Day Master every 10 days. March 15, 1995 was an 乙巳 day, and so was May 14, 1995.
The same lookup can be done online today. The Korea Astronomy and Space Science Institute (KASI) publishes a monthly solar-lunar calendar that gives the lunar date and the year, month and day signs for every date. For March 15, 1995 it shows the day sign 을사 (乙巳), which is the day pillar of the example above. Only the day sign carries over to a saju chart as it stands. That calendar's year and month signs follow the lunar calendar: it gives March 31, 1995 the month sign 庚辰, while this calculator keeps the month pillar 己卯 until the solar term Cheongmyeong (清明, Pure Brightness) on April 5.
Which day counts if you were born close to midnight?
A calendar changes date at midnight. This calculator changes the day pillar at 23:00 in true solar time, when 子 hour (the hour of the Rat, 23:00–00:59) begins. True solar time is clock time corrected for the longitude of the birthplace and for the equation of time. In Seoul on March 15, 1995 it ran 42 minutes behind the clock, so the day pillar changed at 23:42 by the clock.
| Time entered for a birth in Seoul on March 15, 1995 | True solar time | Day pillar | Day Master |
|---|---|---|---|
| 00:10 | 23:28 on March 14 | 乙巳 | 乙, Yin Wood |
| 14:30 (the example above) | 13:48 | 乙巳 | 乙, Yin Wood |
| 23:30 | 22:48 | 乙巳 | 乙, Yin Wood |
| 23:42 | 23:00 | 丙午 | 丙, Yang Fire |
| Birth time unknown | Not used | 乙巳 | 乙, Yin Wood |
The first row falls in the 子 hour that began on the evening of March 14, which this calculator already counts as March 15. The fourth row has just entered the 子 hour that begins on the evening of March 15, so it takes the day pillar of March 16. In both of those rows, the note under the pillar table says that the birth came after 23:00 in true solar time and that the chart counts it as the start of the next day.
Other conventions exist. The Encyclopedia of Korean Culture records that some practitioners divide 子 hour into yajasi (夜子時, 23:00 to midnight) and jeongjasi (正子時, midnight to 01:00) and set the day pillar differently for the two halves. A person born in the hour before midnight can therefore get a different Day Master from a calculator that follows another convention. The page on saju and BaZi conventions compares them, and About and method gives this calculator's rules in full.
Two cases skip the solar-time correction. With "Birth time unknown", the Day Master is the one for the calendar date as entered. With a birthplace that is not in the list, you choose a time zone, and the day pillar changes at 23:00 standard clock time. If daylight saving time was in effect at the birth, that hour is taken off first.