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Imsin Day Pillar (壬申)
— Sword-Edge Metal, metal honed like a blade's edge

Day pillars · 2026.08.25 · 5 min read

The day pillar (ilju 日柱) is the stem-branch pair of the day you were born — the pillar that represents you yourself in Saju (四柱, the Four Pillars). The Imsin day pillar is the 9th of the sixty Gapja (六十甲子, 60 stem-branch pairs). In this note, we'll lay out its structure — Day Master and day branch, Nayin element (napeum ohaeng 納音五行), Gongmang (空亡, the Void) and Twelve Sinsal (十二神殺, twelve symbolic stars) — using calculations from the Mutal Unnie Saju engine.

What kind of pairing is the Imsin day pillar?

Picture great, ceaselessly flowing water sitting on the early autumn of harvest. Im Water (壬水) is an energy of water whose depth is hard to gauge. Even when calm on the surface, it's seen as holding a great current within.

Sin Metal (申金) is the first point where summer's expansion stops and the gathering-in begins. It's said to be a seat of many talents and nimble movement. In Five Elements terms, the Day Master Im is Water and the day branch Sin is Metal — a shape in which your seat supports you. If the idea of a day pillar is new to you, it's worth reading that first.

What does the Nayin element Sword-Edge Metal mean?

It means metal honed like a blade's edge — the metal of a sword tip sharpened again and again. Among the metals of the sixty Gapja, it's the most keenly refined image, so it's read as an energy of quick judgment and decisiveness. The better honed a blade, the less it's swung carelessly, so restraint is also mentioned alongside this Nayin.

The partner that shares Sword-Edge Metal is the Gyeyu day pillar. Of the two, Imsin has a yang stem, so even with the same image it's read as the one that moves first and shows it outwardly.

How do the Day Master Im and the day branch Sin relate?

The hidden stems held in Sin, the day branch of the Imsin day pillar, are Mu, Im and Gyeong. Matching the main stem Gyeong (庚) against the Day Master Im, the Ten God of this seat reads as Indirect Resource.

It sits on an energy that helps you, but in a somewhat unusual way. It's seen as a position where intuition and ideas develop, suited to studying paths others don't take. On days when your thoughts multiply, moving your body is said to be the remedy. If the very idea of the Ten Gods is unfamiliar, we recommend starting with The Ten Gods: the complete guide.

When is the next Imsin day?

An Imsin day comes around once every 60 days. Here are the nearest Imsin days, calculated with the Mutal Unnie Saju engine.

A day carrying the same stem-branch pair as your day pillar is seen as a day when your own energy doubles up. If you jot down how you felt on days like these, your rhythm starts to show. How the daily stem-branch pairs rotate is explained in the story of iljin.

What does Gongmang Sul and Hae mean?

The Void is set by the group (decade, sun 旬) a day pillar belongs to. The Imsin day pillar belongs to the Gapja decade, so its Void branches are Sul·Hae. Sul (戌) and Hae (亥) are the seats left without a partner. When these two characters appear in your birth chart or in a day's stem-branch pair, the energy is seen as having less force behind it than usual.

Gongmang isn't something to fear; it's closer to a marker telling you where to ease off. How Gongmang works across the whole birth chart is described in detail in Gongmang explained.

What does the Jisal position mean?

Sin is the birth position (saengji 生地) in the Three Harmony Water frame (水局) of Sin·Ja·Jin. That's why the day-branch seat of the Imsin day pillar is read as Jisal in the Twelve Sinsal.

Jisal (地殺, Earth Star) is the star of movement and beginnings. When the character in the birth position (saengji) sits in the day branch, a life on the move is said to suit you. It's a seat where your energy actually comes alive with moving house, travel and new surroundings. The full picture of the twelve sinsal is in the Twelve Sinsal complete guide.

Is the day pillar all I need to look at?

The day pillar is two of the Eight Characters. Even with the same Imsin day pillar, a different birth season (month branch) and birth hour make a completely different chart. An Im (壬) born in the depths of winter and an Im (壬) born at the height of summer need different things from the start. So this note introduces the nature of the Imsin pairing — it isn't a personal Saju reading. If you're curious about your whole birth chart, start with the complete guide to reading Saju.