Who were you
before this life? 🔮

Saju (四柱) means "four pillars": the year, month, day and hour of your birth, each written out as two characters. The upper character of a pillar is a heavenly stem (天干), and there are ten of them — Gap, Eul, Byeong, Jeong, Mu, Gi, Gyeong, Sin, Im, Gye. The lower character is an earthly branch (地支), and there are twelve — Ja, Chuk, In, Myo, Jin, Sa, O, Mi, Sin, Yu, Sul, Hae. Four pillars of two characters each makes eight characters, which is why Koreans call the system saju palja, "four pillars, eight characters". Pair stems and branches off in order — Gapja, Eulchuk, Byeongin — and you return to the start after exactly sixty combinations. Those sixty are the sexagenary cycle, and they are the alphabet this test is written in.

The pillar belonging to the day you were born is the day pillar (日柱), and its upper character is the day master (日干). Of all eight characters, Four Pillars astrology treats this single one as "you yourself", and reads the other seven as the world around you. That is exactly why a birth date alone is enough here: your past life comes from the day master, and the day master is fixed the moment the date is known. The hour only nudges the count.

The idea of a past life is far older than Four Pillars astrology. Rebirth travelled from India into East Asia along with Buddhism, and people fell into the habit of reading this life's fortune as an invoice for deeds done in the last one. The Korean joke "you must have saved a nation in a past life", said to anyone with outrageous luck, is a leftover of that habit. Strictly speaking, though, a saju chart contains no past-life field at all. The eight characters are calendar data — a transcription of your birth moment into an old astronomical notation — and whether you read them forwards into the future or backwards into what came before is a matter of interpretation. This page simply chose backwards. If you would rather see the eight characters themselves, the manse-ryeok tool (in Korean) computes a full chart down to the minute of each solar-term boundary.

The ten heavenly stems are the five elements — Wood, Fire, Earth, Metal, Water — each split into a yang (陽) and a yin (陰) version. The same wood behaves quite differently as yang wood (Gap) and yin wood (Eul). Below is what Four Pillars tradition says each day master is made of, and how this test carried that quality into a specific person in a specific civilization. Where our zombie survival test keeps you in one collapsing city, this one uses the whole of recorded history as its stage.

Gap Wood (甲木) · Eul Wood (乙木) — the energy of trees

Gap Wood is the great tree that grows straight up, the timber that becomes pillars and roof beams. It pushes upward, it leads, and once it has chosen a direction it does not bend. Reading that character into the past gives you the chieftain who led a steppe tribe: on a plain where nothing interrupts the horizon, a tall tree is itself the landmark. When the herd lost the road, yours was the tent everyone looked at.

Eul Wood is the flowering plant, the vine, the medicinal herb. It does not push head-on; it climbs around the wall, and when trampled it stands back up. Layer that survivability over a pair of hands that deal in living things and you get the royal gardener and herbal healer. Crowns changed heads, and the garden kept growing under your care regardless.

Byeong Fire (丙火) · Jeong Fire (丁火) — the energy of fire

Byeong Fire is the midday sun: impossible to hide, reaching a long way, holding no grudges afterwards. It is a character that only does its job in front of a crowd, so it became the high priest of a sun temple, the one who timed ten thousand people's worship to the exact moment of sunrise.

Jeong Fire is the oil lamp and the candle. Instead of spreading wide like the sun, it lights one place for a very long time, and the darker it gets the more it matters. That is where the librarian of the Great Library of Alexandria came from — the one who kept the lamps burning through the night so the world's knowledge would not go out.

Mu Earth (戊土) · Gi Earth (己土) — the energy of earth

Mu Earth is the mountain and the levee. Broad, thick, hard to shift, and very good at stacking things. A person like a mountain leaves behind something like a mountain, so this one reads as the master architect who raised pyramids and great walls. The stones you set are still standing thousands of years later.

Gi Earth is the soil of fields and paddies. Rather than blocking, it grows things and holds them. It became the master of a Silk Road caravan, the one who kept people and camels alive in the middle of a desert. Silk reached western tables because of this kind of energy.

Gyeong Metal (庚金) · Sin Metal (辛金) — the energy of metal

Gyeong Metal is unrefined iron and raw ore. It hardens under every blow and decides quickly. This is the legendary blacksmith who handled fire and steel and produced named swords — the owner of a forge where kings queued up to place an order.

Sin Metal is the finished jewel and the needle. Sensitive, precise, unable to tolerate anything crooked. It became the crown jeweller who cut raw stones until a throne was complete. A crown was not a crown until it had passed through your hands.

Im Water (壬水) · Gye Water (癸水) — the energy of water

Im Water is the sea and the great river. Vast in scale, intolerant of being penned into one place. It reads as the exploring captain of the age of sail, the one who steered for the empty part of the map.

Gye Water is rainwater, dew and night fog. It seeps in without a sound and reads what others cannot see. This is the court astrologer who found the future in the movement of the night sky. The king did not start a war without your chart.

There are twelve past lives rather than ten because two further conditions sit on top of the day master. The first is Goegang (魁罡). It names six of the sixty day pillars — Mujin, Gyeongjin, Imjin, Musul, Gyeongsul, Imsul — which Four Pillars lore calls the "chief star" and treats as an extreme, forceful charge of energy. Born on one of those six, your past life becomes the Great Khan of the steppe, the conqueror who swept a continent, regardless of your day master — and your reincarnation count picks up 11 extra points, on the premise that a conqueror's soul is never satisfied with a single life. Exactly 10% of the 22,280 days between 1950 and 2010 land here: 2,228 of them.

The second is the cat of an Egyptian temple. This one is decided not by the day pillar but by the reincarnation count: a computed count of 98 or higher means your past life was not human at all. The logic is that a soul this old runs out of human ancestry, and what waits at the end of the line is a cat that people worshipped as a god. That part is not invented — ancient Egypt genuinely treated cats as incarnations of the goddess Bastet, and there are records of the death penalty for harming one. Over the same period the cat appears on just 97 of 22,280 days, about 0.4%, which makes it the rarest result on the page. Note that a Goegang day pillar still becomes the cat if the count clears 98 — even a Great Khan's soul, traced back far enough, turns out to have been a cat.

The bond carried over and the feud running for several lives under your result are not generated from the elements' generating and controlling cycles. They were paired by asking how two past lives would plausibly have tangled with each other in their own era. The chieftain's ally is the blacksmith who forged the tribe's weapons, and his adversary is the master architect who walled the steppe off; the captain's ally is the caravan master who joined sea route to land route, and his adversary is the librarian who has not returned the borrowed ship's log for several lifetimes now.

The count is assembled in the order below. The rules are invented to fit the premise, but they are applied identically to everyone.

1. Base score — your starting point depends on your day master's element: Wood 46, Fire 41, Earth 54, Metal 49, Water 57. Deep water and long-settled earth are treated as old souls; fire, which has to be lit fresh every time, is treated as a young one.

2. Relations with the other characters — the elements of your year, month and day branches (plus the hour branch, if you entered a time) are scored by how they relate to your day master. The resource star (印星) — what produces you — is the largest bonus at +7. In Four Pillars terms the resource star means mother, root, inheritance, which this test reads as "memory carried over from a past life", hence top marks. Then the authority star that governs you is +3 (karma accumulated across many lives), your output star is +1, a peer of the same element is −2, and the wealth star you control is −4. Wealth grips at the things of this life, so it pulls you toward the young end. For comparison, our AI robot test gives its biggest bonus to peers and output instead. Same eight characters, different world, inverted scoring.

3. Positional weights — the year branch is multiplied by 1.7, the month branch by 1.5, the day branch by 1.0, the hour branch by 0.6. Most saju-based tests weight the month branch heaviest, because it carries the season of birth. This one is the exception: the year pillar is the ancestral seat — the place of what existed before you — and in a test that reads backwards, the roots deserve the weight.

4. Yin, yang and Goegang — a yin stem (Eul, Jeong, Gi, Sin, Gye) gets +2 and a yang stem (Gap, Byeong, Mu, Gyeong, Im) gets −3, because yin energy is the kind that seeps in and accumulates. On top of that, the six Goegang day pillars add +11.

5. Scatter — computed only this far, everyone sharing a day pillar would clump onto nearly the same number. So the birth-date string is fed to a fixed hash function and two deviations, of up to ±28 and ±6.5, are added from its output. These are not random numbers; they are derived from the date, so the same date always receives the same deviations.

Finally, anything above 93 is compressed to 0.4 of its excess, anything below 9 is halved, and the result is clipped into the 3–99 range. The top is squeezed harder because 98 is the cat threshold and the cat is supposed to be hard to reach. The floor sits at 3 rather than 1 purely as world-building: no soul looks up its own reincarnation count during its very first life, so everyone starts at least on their third. Run every date from 1950 to 2010 and the mean comes out at 54.1 with a median of 54 — and both extremes, 3 and 99, really do occur.

The "top N% by soul age" line on the result screen is not a comparison against other people who took this test. Your input never leaves the browser, so there would be no way to do that. What the page carries instead is a percentile table computed in advance.

The table was built like this. For every one of the 22,280 days from 1 January 1950 to 31 December 2010, the reincarnation count was computed with the birth time treated as unknown. Then, for each count from 3 to 99, we counted what share of all those dates (in permille, ‰) score at or above that value, and stored the answer as a 97-slot table. The result screen simply looks your count up in that table and converts it to a percentage. Because more rebirths means an older soul, a higher count means a higher "soul age" ranking.

A few reference points: a count of 54 sits almost exactly at the halfway mark; 60 is top 41%; 70 is top 24%; 80 is top 12%; 90 is top 4%; 95 is top 2%. Drop below the top 50% — that is, toward fewer rebirths — and the badge turns teal, the label becomes "a bright new soul", and the number flips to read "top N% among new souls" instead. On the new-soul side, fewer rebirths means a better rank, so whichever end you land on there is something to brag about.

This page never calls a random function while producing your result. Every value on the screen is computed from your birth date, and from the time if you chose one.

The sequence goes like this. The date is first converted to a running day number, and taking that modulo 60 fixes the day pillar — the sexagenary cycle turns over every sixty days with no exceptions, so this step is exact. The year and month pillars are a different matter. In saju, a year does not begin on 1 January, and it does not begin at Lunar New Year either: it begins at Ipchun, the solar term marking the start of spring. Months advance whenever one of the twelve principal solar terms passes. This page embeds a table of those term boundaries, minute by minute, from 1900 onward, so for anyone born in early February it checks the clock to decide whether their year pillar still belongs to last year or already to the new one.

Apply the formula above to the resulting eight characters — six, if the time is unknown — and you get a score; even the final deviations come out of a hash of the birth-date string. Press the button on any day, on any device, and the same birth date returns the same past life and the same number. Comparing results with a friend only means anything because of this property.

My birthday is on the lunar calendar — can I enter it as is?

No. Input is solar, meaning the Gregorian calendar. If you only know a lunar birthday, convert it to a solar date first with the lunar–solar converter (in Korean) and enter that. The perpetual calendar keys on solar terms — the sun's actual position — rather than lunar dates, so entering a lunar date as if it were solar produces a chart that is off by nearly a month.

Does not knowing my birth time change the result?

Usually the past life stays the same, because it is decided by the day pillar and the day pillar depends on the date alone. What moves is the reincarnation count. Adding a time brings in one more character, the hour branch, at 0.6 weight, and it also changes the input to the hash that produces the deviations. In practice the count shifts by about 19 on average between "time entered" and "time unknown". If you pick no time, noon is used as the representative value. The exception is the cat: because the time can push a count over or under the 98 threshold, roughly 4% of dates between 1950 and 2010 become the temple cat, or stop being it, depending on the hour.

My result differs from other perpetual calendars

This test computes with one fixed convention and no options. Time is accepted only as the twelve two-hour branches, using the midpoint of each slot, and there is no 30-minute standard-time correction and no late-night-hour (yajasi) setting for whether a birth after 11 p.m. counts as the next day's pillar. The day pillar is fixed by date alone, regardless of time. So if you were born around 11 p.m., or on the day of a solar-term boundary, results can diverge from a rigorous chart. When you need one that handles those edge cases, use the manse-ryeok tool (in Korean): it reflects term boundaries to the minute, and standard-time correction and yajasi can each be toggled.

My reincarnation count came out very low

The items that pull toward the young end are the wealth star (the element your day master controls, −4 each) and peers (the same element, −2 each). With no resource star anywhere in your branches, there is not much road for the number to climb. But a low number on this scale is not a bad result. In a world full of old souls, a new soul only a few lives in is the rarer thing — and below the top 50% the result screen inverts the ranking and shows "top N% among new souls" instead. If you want to know what the wealth and resource stars actually mean in a real chart, Yaong Myeongni (in Korean) explains the eight characters one by one.

Does the result link contain my birth date?

No. The shared link carries exactly four values folded into a single number: the past-life number, the reincarnation count, the top percentage, and the day-pillar index. Your birth date and birth time are not included, and they cannot be recovered from what is included — the day-pillar index is a value that repeats every sixty days, so on its own it cannot identify a date. Whoever opens your link sees your result screen and an empty input form, nothing more.

Why are there only twelve past lives?

Because there are ten day masters, plus the Goegang condition and the cat condition, which makes twelve. In exchange, the reincarnation count from 3 to 99, the soul-age percentile, and sixty different one-line day-pillar readings combine so that two people with the same past life still see meaningfully different screens.

Do I have to actually believe in past lives?

You do not, and neither does this test. Past lives have never been scientifically demonstrated, and the reincarnation count on this page is nothing more than the number produced by the formula printed above. The perpetual-calendar part is real, though — the day pillar on your screen is genuine calendar data, and what Four Pillars astrology reads out of those eight characters can be found at Yaong Myeongni (in Korean). You can disbelieve the past life and still enjoy the half hour spent comparing counts with your friends.

If you have read this far you will have guessed the answer: this is entertainment. The perpetual-calendar portion is a real computation running on real solar-term data, and ancient Egypt really did hold cats sacred — but the rules that turn eight characters into past lives across world civilizations, and then attach a number of rebirths to them, were all invented by this page. Four Pillars astrology has no concept of a "reincarnation count", and no school of it calculates past lives from a birth chart.

One more thing worth saying: none of the twelve past lives here is a loser. Chieftain, librarian or cat, every one of them was somebody in their own era. That is simply what past-life readings are like — nobody has ever shared an appraisal saying they were an unremarkable farmer. If the saju side of this has caught your interest, check your own eight characters with the manse-ryeok tool (in Korean), and read what those characters mean at Yaong Myeongni (in Korean).