Day Master Compatibility: Why Couples Compare Day Pillars

Day master compatibility compares the day stems in two saju charts. The day stem, called the day master or ilgan (일간 日干), is traditionally read as the “you” of the chart, so comparing two of them is the most personal layer of saju compatibility. Practitioners check three things: how the two elements relate, whether the stems form a classic combination, and how the two day branches interact.

Saju (사주 四柱, “four pillars”) builds a chart from the year, month, day and hour of birth. Each pillar has a heavenly stem on top and an earthly branch below. Year animals are fun, but when Koreans get serious about gunghap (궁합 宮合, compatibility), the conversation usually moves to the day pillar.

Here is how to read the day pillar step by step, with the tables you need.

Step 1: know the ten day masters

There are ten heavenly stems, or cheongan (천간 天干). Each is one of five elements in a yang or yin form:

Stem	Name	Element	Polarity	Classic partner (stem combination)	SajuBunny tteok
甲	gap	Wood	Yang	己 gi	Garaetteok
乙	eul	Wood	Yin	庚 gyeong	Songpyeon
丙	byeong	Fire	Yang	辛 sin	Mujigae-tteok
丁	jeong	Fire	Yin	壬 im	Kkultteok
戊	mu	Earth	Yang	癸 gye	Sirutteok
己	gi	Earth	Yin	甲 gap	Baekseolgi
庚	gyeong	Metal	Yang	乙 eul	Jeolpyeon
辛	sin	Metal	Yin	丙 byeong	Gyeongdan
壬	im	Water	Yang	丁 jeong	Yakbap
癸	gye	Water	Yin	戊 mu	Injeolmi

Find both of your day stems in the table. The tteok column is SajuBunny’s playful rice-cake mascot for each day master.

Step 2: see how the two elements relate

Five-element theory, known as ohaeng (오행 五行), links the elements through two cycles:

Generating (상생 sangsaeng): wood → fire → earth → metal → water → wood
Controlling (상극 sanggeuk): wood → earth → water → fire → metal → wood

Between any two day masters there are only five possible relationships. Each one has a ten-god label (십성 sipseong 十星) from the point of view of Person A:

Relationship	Example	Ten-god label for A	Plain-English feel
Same element	Wood + Wood	Bigyeon / Geopjae (Peer / Rival)	Equals, teammates, sometimes competitors
A feeds B	Wood → Fire	Siksin / Sanggwan (Creator / Performer)	A inspires and expresses; B receives
B feeds A	Water → Wood	Pyeonin / Jeongin (Unconventional / Nurturing mentor)	B supports and teaches A
A controls B	Wood → Earth	Pyeonjae / Jeongjae (Adventurer / Steady wealth)	A shapes and manages; B grounds A
B controls A	Metal → Wood	Pyeongwan / Jeonggwan (Challenger / Guardian)	B sets structure; A is stretched and refined

The first word in each pair is used when the two stems share the same polarity (both yang or both yin). The second word is used when they differ.

In saju symbolism, a relationship reads differently from each side. If you are wood and your partner is fire, you “feed” them and they get their spark from you. From their side, you are their mentor element. That is why many practitioners read both directions before saying anything.

A historical note. Classical texts gave these labels gendered spouse meanings. A Korea Times saju column describes the older rule: a woman’s “officer” star stood for her husband, and a man’s “wealth” star stood for his wife. Many modern readers now apply the relationships to any couple, whatever their genders.

Step 3: check for a stem combination

The five classic stem combinations, called cheongan-hap (천간합 天干合), pair stems that sit five places apart in the cycle, always one yang with one yin:

Combination	Transforms toward
甲 + 己	Earth
乙 + 庚	Metal
丙 + 辛	Water
丁 + 壬	Wood
戊 + 癸	Fire

When two day masters form one of these pairs, practitioners traditionally read a natural pull, a “we fit” feeling. Look closely and something interesting shows up: every combining pair is also a controlling pair. 甲 wood controls 己 earth, 庚 metal controls 乙 wood, and so on. So the classic “attraction” pairs mix tension with pull. Many long-married couples would recognize that feeling.

Step 4: compare the day branches

The branch under each day stem is often called the “spouse palace” (배우자궁 baeujagung). It is read as your private, at-home self. Compare the two day branches using the same branch relationships used for zodiac animals:

Yukhap (육합 六合): 子丑, 寅亥, 卯戌, 辰酉, 巳申, 午未, a one-to-one bond
Samhap (삼합 三合): 申子辰, 寅午戌, 巳酉丑, 亥卯未, shared direction
Chung (충 沖): 子午, 丑未, 寅申, 卯酉, 辰戌, 巳亥, contrast and movement
Wonjin (원진 怨嗔): 子未, 丑午, 寅酉, 卯申, 辰亥, 巳戌, small irritations to name early

A day-branch clash does not cancel a warm day-master link. Most couples have a mix, and that is normal.

Two worked examples

丙 byeong (yang fire) + 辛 sin (yin metal). Fire controls metal, so from 丙’s side 辛 is a wealth star, and from 辛’s side 丙 is an officer star. The pair is also the classic 丙辛 combination. The traditional reading is strong attraction with a need for gentleness. The sunny partner should not “melt” the refined one. In SajuBunny terms, it is a rainbow tteok and a gyeongdan sharing a plate.

甲 gap (yang wood) + 丁 jeong (yin fire). Wood feeds fire, and the polarities differ, so 甲 plays the Performer role (sanggwan) toward 丁, and 丁 sees 甲 as a nurturing mentor (jeongin). It is traditionally read as a warm, supportive flow. The prompt for this pair is balance: does the wood partner get support back?

How to use this without overthinking it

Read both directions. Every relationship has two sides.
Treat control as structure, not dominance. In the cycles, control means shaping, like a riverbank guiding water.
Use the result as a conversation starter: “The chart says I’m your challenger. Do you feel that?”
Remember that the rest of both charts, and the actual people, matter more than one pair of stems.

FAQ

What is a day master in saju?

The day master, or ilgan, is the heavenly stem of your day pillar, one of ten stems from 甲 gap to 癸 gye. Saju practitioners traditionally treat it as the core self of the chart. Every other character is read in relation to it through the five-element cycles, which is why it sits at the center of compatibility readings.

Which day masters are most compatible?

There is no single best pair. Practitioners often highlight the five stem combinations: 甲己, 乙庚, 丙辛, 丁壬 and 戊癸. They also highlight generating relationships, where one partner’s element feeds the other’s. But same-element pairs and controlling pairs can work beautifully too, because they bring teamwork or healthy structure. The full chart always adds nuance.

What does it mean if my partner’s day master controls mine?

In saju symbolism, being “controlled” means your partner’s element shapes or challenges yours, like metal carving wood. Traditionally this is the officer or challenger star. It can feel like being stretched, organized or held to a standard. It is a description of dynamics, not a warning. Many people value a partner who helps them grow.

Do I need birth times to compare day pillars?

No. The day pillar comes from the birth date, so you can compare day masters and day branches without knowing birth hours. Just note that the saju day changes at the start of the 子 hour, around 23:00, so late-night births are worth double-checking. Birth times add the hour pillars, which help a fuller reading.

Try it with the Moon Rabbit

Find your day master in about 30 seconds with a free saju card. Then open the pro chart to see your day branch and every other pillar. Compare with someone you like and see what the Moon Rabbit notices.

Saju is a cultural tradition, not a science. SajuBunny readings are for fun and self-reflection, not professional advice.

Sources

For fun and self-reflection. Saju is a traditional way of looking at yourself, not a prediction or professional advice.