If the Zombie Apocalypse Hits,
What's Your Role? 🧟

Saju (사주) is Korea's traditional Four Pillars birth-chart system, the same one behind the fortune-telling booths of Seoul and the new-year readings Koreans still line up for. It transcribes the year, month, day, and hour of your birth into four "pillars" of two characters each. The upper character of each pillar is one of the ten heavenly stems (Gap, Eul, Byeong, Jeong, Mu, Gi, Gyeong, Sin, Im, Gye), and the lower one is one of the twelve earthly branches — the same twelve animals of the East Asian zodiac. Four pillars, two characters each: eight characters in total, which is why Koreans also call it saju palja, "four pillars, eight characters". Pairing stems with branches in order produces a cycle that returns to its start after sixty combinations — the famous sexagenary cycle that also names years (2024, for instance, was a "Blue Dragon" year in this system).

The pillar for the day you were born is the day pillar, and its upper character is the day master — the conventional English term used by Four Pillars practitioners. Korean saju theory treats this one character as "you", and reads the other seven characters as the environment surrounding you. That is why this test can assign a role from your birth date alone: the role comes from the day master, and the day master is fixed the moment your birth date is.

The eight characters themselves are closer to calendar data than to a fortune. Old East Asian calendars printed each day's stem-branch pair right on the page; a saju chart simply transcribes your moment of birth into that old notation. What the characters mean is interpretation, and interpretation is where schools diverge. The zombie role assignments below are one such interpretation — not orthodox saju doctrine but this page's own house rules. If you want to see your actual eight characters, the Korean calendrical calculator (in Korean) shows your full chart down to the minute of each seasonal term.

The ten heavenly stems are the five elements — Wood, Fire, Earth, Metal, Water — each split into a yang and a yin form. Two Wood stems are still two different kinds of wood: yang Wood (Gap) and yin Wood (Eul) behave nothing alike. Below is how saju tradition characterizes each day master, and where this test stationed that character when the dead start walking.

Gap 甲 and Eul 乙 — the Wood day masters

Gap, yang Wood, is the great tree growing straight toward the sky — timber fit for the pillars of a building. It starts things, it leads, and once it picks a direction it does not bend. So this test reads Gap as the Barricade Architect: the one who raises pillars in a collapsing building — the person who builds structure.

Eul, yin Wood, is the flower and the vine. It never pushes head-on like a big tree; it climbs the wall, goes around, and stands back up after being trampled. Its softness is its survival skill, so it becomes the Master of Stealth. A vine never needs to beat the axe — that is the Eul way.

Byeong 丙 and Jeong 丁 — the Fire day masters

Byeong, yang Fire, is the midday sun: impossible to hide, reaching everywhere, holding no grudges — and utterly incapable of conserving fuel. That is why it charges at the front as the Vanguard Captain.

Jeong, yin Fire, is the lamp and the candle. Not as bright as the sun, but it earns its keep precisely when it gets dark, and it can light one spot for a very long time. Night watches and bedside vigils suit it, so it becomes the Keeper of the Campfire.

Mu 戊 and Gi 己 — the Earth day masters

Mu, yang Earth, is the mountain and the levee: broad, thick, unshakable — and it hates to move. Holding out is how it wins, so it stands as the Fortress Gatekeeper.

Gi, yin Earth, is the soil of fields and paddies. Instead of blocking like a mountain, it grows things and stores things. It feeds the camp after the canned food runs out: the Garden Overlord.

Gyeong 庚 and Sin 辛 — the Metal day masters

Gyeong, yang Metal, is raw ore, pig iron, the axe. It hardens with every blow and decides fast. Gathering scattered scrap and turning it into weapons, it becomes the Armory Master.

Sin, yin Metal, is the finished jewel, the needle, the well-honed blade: precise, fastidious, allergic to sloppiness. That is where the Cold-Eyed Sniper comes from — one shot, done.

Im 壬 and Gye 癸 — the Water day masters

Im, yang Water, is the ocean and the great river. Big in scale, it cannot stand being boxed in, and it finds new paths where roads are blocked: the Route Pioneer.

Gye, yin Water, is rain, dew, spring water — seeping quietly into everything, touching everywhere. It collects rumors and signals and turns them into maps: the Intel Broker.

The eleventh and twelfth roles — Goegang and Zombie No. 1

There are twelve roles rather than ten because two special conditions sit on top of the day masters. The first is Goegang (괴강, 魁罡): six specific day pillars out of the sixty — Mujin, Gyeongjin, Imjin, Musul, Gyeongsul, Imsul — that saju tradition calls the "chieftain star", an extreme and forceful energy. Born on one of these six pillars, you become The Last Survivor regardless of day master, and your survival score gets +16. Exactly 10% of all dates between 1950 and 2010 fall here.

The second is Zombie No. 1. This one is decided by score, not pillar: if your computed survival rate lands below 5%, your role flips to Zombie No. 1. Only 63 of the 22,280 days in the same period — about 0.28% — produce it. In other words, it is the rare pull.

The best teammate and worst pairing under your result follow the same logic as the score. The best teammate carries the day master of the element that feeds yours — the "resource" star in saju terms (Water for a Gap Wood, Wood for a Byeong Fire) — while the worst pairing carries the element that strikes yours, the "officer" star (Metal against Wood, Water against Fire). In the survival formula below, the resource star is the biggest bonus and the officer star the biggest penalty, by the same reasoning.

The survival rate is built in the following order. The rules are invented for the zombie setting, but the same rules apply to everyone.

1. Base score — Your starting point depends on the day master's element: Wood 47, Fire 54, Earth 51, Metal 56, Water 44.

2. Relations with the rest of the chart — The elements of your year, month, and day branches (plus the hour branch if you enter a birth time) are scored by their relationship to your day master: same element (peers) +3, the element you produce (output) 0, the element you control (wealth) −1, the element that controls you (officer) −8, the element that produces you (resource) +6. The month branch is weighted ×1.6, the day branch ×1.4, the year branch ×1.0, and the hour branch ×0.8. Weighting the month heaviest follows saju convention, which treats the season of birth as the root of the whole chart.

3. Yin and yang — Yang day masters (Gap, Byeong, Mu, Gyeong, Im) get +2; yin day masters (Eul, Jeong, Gi, Sin, Gye) get −2. A world of head-on collisions favors the yang stems — that is the house rule here.

4. Goegang — The six chieftain-star pillars get +16, the single largest item in the whole formula.

5. Scatter — Up to this point, people who share a day pillar would score nearly identically. So the birth-date string is run through a fixed hash function, and the result adds two deterministic offsets of up to ±23 and ±6. These are computed from the date, not drawn at random — the same date always receives the same offsets.

Finally, anything above 92 or below 8 is gently compressed, and the result is clamped to 1–99. Run over every date from 1950 to 2010, the formula averages 51.9 with a median of 52, and both extremes — 1% and 99% — actually occur.

The "top N%" badge on your result is not a comparison with other people who took this test. Your input is never sent anywhere, so there is nothing to compare against. Instead, this page ships with a precomputed percentile table.

The table was built like this: for every one of the 22,280 dates from January 1, 1950 through December 31, 2010, the survival rate was computed with the birth time treated as unknown. Then, for each survival value from 1 to 99, we counted what fraction of all dates (in per-mille) score at or above that value, and stored the 99 numbers in the page. Your result screen simply looks your survival rate up in that table.

So read the number as "top N% of all possible birth dates", not "top N% of people who took this test". A few reference points: a survival rate of 52% is exactly the top 50%, 70% puts you in the top 19%, 80% in the top 8%, and 90% in the top 3%. Below the halfway line, the badge flips to "bottom N%".

This page uses no random function anywhere in producing a result. Every value on screen is computed from your birth date (and the birth time, if you chose one).

The order goes like this. First, your birth date is converted to a running day number; the remainder after dividing by 60 fixes the day pillar, because the sexagenary cycle rolls over every sixty days without exception. The year and month pillars are trickier. In saju, the year does not change on January 1 or on Lunar New Year but at Ipchun, the "start of spring" seasonal term, and the month rolls over at each of the twelve solar terms. This page embeds a table of those term times, minute by minute, from 1900 onward — so for someone born in early February, it checks against the clock whether their year pillar is still last year's or already the new one.

The resulting eight (or six, without a birth time) characters go through the formula above, and even the final scatter offsets come from a hash of the birth-date string. The upshot: on any day, on any device, the same birthday yields the same role and the same numbers. Comparing results with friends only means something because of this property.

My birthday is on the lunar calendar. Can I enter it as-is?

No. The input expects the Gregorian (solar) calendar. Saju computation runs on solar terms — the position of the sun — not on lunar dates, so entering a lunar date directly would shift your whole chart by up to a month. If you only know your lunar birthday, convert it to a solar date first (K-magpie has a lunar–solar converter, in Korean).

Does not knowing my birth time change the result?

Your role does not change: the role comes from the day pillar, and the day pillar is fixed by the date alone. What changes is the survival number. Adding a time contributes one extra branch at ×0.8 weight and also changes the hash input for the scatter offsets — in practice the survival rate moves by about 16 points on average with versus without a time. If you leave the time out, noon is used as the representative value. In a handful of dates hovering around 5%, the birth time can decide whether you become Zombie No. 1 or not.

Another saju calculator gives me a different chart

This test computes with one fixed convention and no options. Birth time is taken only as one of the twelve traditional two-hour slots, using each slot's midpoint; there is no 30-minute standard-time correction and no "late Rat hour" rule (whether 11 p.m.+ counts as the next day), both of which vary by school. The day pillar is also fixed by date alone, regardless of time. So if you were born near 11 p.m. or on the day of a seasonal-term changeover, a full-featured calculator may differ. For a chart that handles those boundary cases, use the calendrical calculator (in Korean), which applies term times to the minute and lets you toggle both conventions.

My survival rate came out painfully low

The biggest penalty in the formula is the officer star — the element that strikes your day master — at −8 per branch. Several of them will drag the score down visibly. But in actual saju theory the officer star is not a bad character at all: it stands for discipline, responsibility, and institutions. This test merely decided that in a world of sprinting zombies, discipline slows you down — a house rule, not a verdict of Korean astrology. If you are curious what those characters mean in a real reading, Yaong Myeongni (in Korean) explains all eight.

Does the shared link contain my birth date?

No. The share link carries only four result values — role number, survival rate, percentile, and day-pillar number — packed into a single integer. Your birth date and time are not included and cannot be reconstructed from it. Whoever opens your link sees only your result screen.

Why are there only 12 roles?

Because there are 10 day masters, plus the Goegang pillars and the Zombie No. 1 condition. Within those 12, though, the survival rate (1–99), the percentile, and one of 60 day-pillar one-liners combine — so two people with the same role still get different screens.

If you have read this far you have probably guessed: this test is for entertainment only. The calendrical engine underneath is a genuine computation over real seasonal-term data — but the rules that map eight characters onto zombie roles and stamp a percentage on your survival are entirely this page's invention. There is no concept of a "zombie apocalypse survival rate" in Korean saju.

Also, the number predicts no real-world risk of any kind. There is no reason to worry about a low score or to relax over a high one. The intended use is putting two phones side by side and arguing about who gets bitten first. If the saju side caught your interest, the calendrical calculator (in Korean) shows your own eight characters, and Yaong Myeongni (in Korean) explains what they mean.