If you had been born in
the Joseon dynasty 🪶

Saju (四柱) means "four pillars": the year, month, day and hour of a birth, each written as two characters. The upper one is a heavenly stem (天干) — Gap, Eul, Byeong, Jeong, Mu, Gi, Gyeong, Sin, Im, Gye — and the lower an earthly branch (地支) — ja, chuk, in, myo, jin, sa, o, mi, sin, yu, sul, hae. Eight characters in all, hence saju palja. Paired in order they return to the start after sixty combinations: the sexagenary cycle, the same notation the Annals of the Joseon Dynasty used for dates — not "the fourteenth day" but "the Imjin day".

The pillar of your birth day is the day pillar (日柱) and its upper character the day master (日干). Korean practice treats that one character as "you yourself" and the other seven as the world around you — which is why a date alone is enough here.

In Joseon this was not only a street trade: the Gwansanggam (觀象監), the bureau of astronomy and calendars, held a division called Myeonggwahak (命課學) that chose auspicious dates for royal ceremonies, staffed through its own examination, the Eumyanggwa (陰陽科). But how to read the characters is interpretation, and the assignments below are rules this page invented. For the characters themselves, use the manseryeok tool (in Korean).

The ten stems are the five elements — Wood, Fire, Earth, Metal, Water — each split into yang (陽) and yin (陰). Here is how each reads, and which Joseon seat it was moved into.

Gap Wood (甲木) · Eul Wood (乙木) — trees

Gap Wood is the great tree that becomes pillars and ridgepoles: it leads and does not bend. Hence the Royal Palace Master Carpenter (dopyeonsu), the master builder who directed every carpenter on a palace rebuild.

Eul Wood is the vine and the healing herb — it climbs around the wall and stands up again when trampled. Hence the Finest Physician in Hanyang, Hanyang being old Seoul.

Byeong Fire (丙火) · Jeong Fire (丁火) — fire

Byeong Fire is the midday sun, impossible to hide and useless without an audience: the Marketplace Storyteller (jeongisu), a real Joseon job — reading novels aloud in the street for coins, famously stopping at the worst possible moment.

Jeong Fire is the lamp and the hearth, heating one spot a long time: the Head Chef of the Royal Kitchen (suragan suksu), the suragan being the kitchen that prepared the king's table.

Mu Earth (戊土) · Gi Earth (己土) — earth

Mu Earth is mountain and embankment: broad, unshakable, good at accumulating — the Ten-Thousand-Sack Landowner (manseokkun, the Korean idiom for huge rural wealth).

Gi Earth is field soil: it raises rather than blocks, and people gather on it. Hence the Tavern Keeper (jumak daebang) — the jumak was the roadside inn where every rumour stopped over.

Gyeong Metal (庚金) · Sin Metal (辛金) — metal

Gyeong Metal is raw iron and the axe, hardening the more it is struck: the Top Scorer of the Military Examination (mugwa jangwon) — Joseon examined military officers as it did civil ones.

Sin Metal is the cut jewel and the honed blade, intolerant of anything out of place: the Inspector of the Censorate (Saheonbu gamchal), the office that audited officials and impeached the corrupt.

Im Water (壬水) · Gye Water (癸水) — water

Im Water is sea and great river, too large to be penned in: the Chief of the Peddlers (bobusang daebang), the bobusang being licensed pedlars who carried goods across all eight provinces.

Gye Water is rain and dew, seeping in silently: the Greatest Face Reader in Hanyang (gwansangga), who judged a future from one look at a face.

The eleventh and twelfth — Goegang, and a score of 97

Two conditions sit on top of the day master. The first is Goegang (魁罡): six of the sixty day pillars — Mujin, Gyeongjin, Imjin, Musul, Gyeongsul, Imsul — which lore calls the "chief star". Born on one, you become the Secret Royal Inspector (amhaeng-eosa) whatever your day master, and take 12 extra points. Every sageuk fan knows him: an official travelling in disguise with the king's horse warrant (mapae), who reveals himself with "The Secret Royal Inspector is here!" and arrests a corrupt magistrate on the spot. Six in sixty is exactly 10% — 2,228 of the 22,280 days from 1950 to 2010 — and since all six carry Mu, Gyeong or Im, only the landowner, the officer and the peddler chief lose people to it.

The second is the Chief State Councillor (yeonguijeong), head of the State Council and the highest office a subject could hold. It goes by score: not Goegang, and 97 or above — 132 days out of 22,280, or 0.59%.

The best colleague and arch-rival are not element cycles but how two jobs would tangle in a Joseon street: the physician's ally is the royal cook, his rival the tavern keeper selling the drink he keeps banning; the storyteller's ally is that same tavern keeper, whose yard the crowd forms in, and his rival the inspector whose job is breaking crowds up.

The rules are arbitrary, chosen to fit a Joseon setting, but everyone gets the same ones.

1. Base score — by day-master element: Wood 50, Fire 46, Earth 57, Metal 53, Water 49. Earth, meaning property and full granaries, starts highest; Fire, the flashy element, lowest.

2. Relations — the elements of the year, month and day branches (plus the hour, if given) are scored against your day master: authority star (官星), which governs you, +8; wealth +4, resource +2, output −1, peers (your own element) −5. Authority means office and discipline, so a Joseon world rewards it most; peers are the rivals competing for your seat. In our zombie survival test discipline gets you killed, so the same star is the maximum penalty there.

3. Weights — month ×1.6, year ×1.4, day ×1.1, hour ×0.8. Month heaviest follows the convention of treating the birth season (月令) as a chart's root; year above day is Joseon-specific, since the year pillar is the seat of ancestors, and family standing decided who could sit an examination at all.

4. Yin, yang, Goegang — yang stems +3, yin stems −2, the six Goegang pillars a further +12.

5. Scatter — otherwise people sharing a day pillar would clump, so the date string is hashed and two deviations of up to ±26 and ±6 drawn from it. Not random: the same date always gets the same scatter.

Above 93 or below 7 is then squashed by half and clipped to 1–99. Across 1950–2010 the mean is 59.0 and the median 59, and both 1 and 99 occur. Under 30 a short consoling paragraph is prefixed to your reading — 6.5% of dates land there.

Nokbong (祿俸) was the salary Joseon paid its officials, graded by rank in a table called the nokgwa (祿科): eighteen grades from 1439 under King Sejong, cut to twelve in 1647 and thirteen in 1721. Payment went from twice a year to four times, and monthly late in the dynasty; to collect it an official took a warrant (nokpae) to the state granary, the Gwangheungchang (廣興倉), and drew the goods in kind.

Nor was it only rice: grain mixed with soybeans and wheat, plus silk and hemp cloth and paper money called jeohwa. In the early Joseon period the highest rank drew 97 seok of grain, 21 bolts of hemp and 10 sheets of paper money a year; the lowest of nine ranks drew 12 seok, 2 bolts and 1 sheet. National salary spending ran 100,000–140,000 seok a year — over half the land tax. After grants of land to officials lapsed in 1556, nokbong was the only pay there was.

The number on this screen is different: it is derived from your success score. With the score as p, the base is 20 + (p ÷ 99)^1.7 × 2,350 seom, times a 0.85–1.15 wobble from a hash of the date, clipped to 20–2,500 seom. A score of 50 gives roughly 750 seom, 90 lands near 2,000, and the median across 1950–2010 is 991.

A seom (or seok) is ten mal — about 180 litres, roughly 144 kg of rice. The modern figure is a flat 180 US dollars per seom, a rate this page picked, not a rice price.

The scale is an order of magnitude off the real thing: when the highest rank drew 97 seok, 2,500 seom is impossible, and five of the twelve occupations (landowner, tavern keeper, peddler chief, storyteller, face reader) drew no state salary at all. Read it as "what you would have been making in Joseon", stipend and harvest and trade bundled together.

It is not a comparison against other people who took this test — your input never leaves your browser. Instead the page carries a precomputed percentile table: for every one of the 22,280 days from 1 January 1950 to 31 December 2010 the score was computed with the birth time unknown, and for each score from 1 to 99 we counted what fraction of dates scores at or above it. So it reads as "top N% of all possible birth dates". A score of 60 is top 49%, 70 is top 31%, 80 is top 16%, 90 is top 6%, 97 is top 2%. Below the top 50% the badge turns green and reads "King of the Marketplace", where 50.7% of dates land — half of everyone had no connection to office, so there is little to feel cheated about.

No random function is called anywhere; every value comes from the birth date and the hour if you chose one.

The date becomes a running day number taken modulo 60, which fixes the day pillar — the sexagenary cycle rolls over every sixty days with no exceptions. Year and month pillars are harder: in saju the year turns not on 1 January and not at Lunar New Year but at Ipchun, the solar term starting spring, usually 3–5 February, and the month advances at each of the twelve principal solar terms. This page embeds those boundaries minute by minute from 1900 onward, so a birth in early February is checked against the clock to see whether the year pillar is still last year's.

The scatter and the stipend wobble come from a hash of the date too, so any day, on any device, the same birth date gives the same occupation and the same numbers. Comparing with a friend only means anything because of that.

My birthday is lunar — can I enter it as is?

No. Input is solar (Gregorian); convert first with the lunar–solar converter (in Korean). The calendar keys on solar terms, not lunar dates, so a lunar date entered as-is is off by nearly a month.

Does not knowing my birth time change the result?

The occupation usually stays, since it comes from the day pillar and that depends on the date alone. The score moves: a time adds the hour branch at ×0.8 and changes the hash input, shifting it by about 18 points on average. With no time, noon is used. The exception is the Chief State Councillor — a time can push a score across the 97 threshold, so about 8% of dates flip by hour of birth.

My result differs from other perpetual calendars

This test uses one fixed convention and no options: time only as the twelve two-hour branches at each slot's midpoint, no standard-time correction, no late-night-hour (yajasi) setting, day pillar fixed by date alone. A birth around 11 p.m., or on a term boundary, can therefore diverge from a rigorous chart — the manseryeok tool (in Korean) handles those cases.

My success score came out very low

The heaviest penalty is peers (比劫) — your own element in the branches — at −5 each, and with no authority star there is little road left. But this scale measures one thing: fitness for officialdom. In Four Pillars practice peers mean siblings, colleagues and your own strength, and a chart light on authority usually reads as someone who does well outside an organisation. Yaong Myeongni (in Korean) explains the characters in a real chart.

Does the result link contain my birth date?

No. It carries five values folded into one number: occupation, success score, top %, stipend in seom and day-pillar number. Your date and hour are not in it and cannot be recovered — the day-pillar number repeats every sixty days, so it identifies nothing alone.

Why only 12 occupations?

Ten day masters, plus the Goegang and score-97 conditions. In exchange the score, the top %, the stipend and a one-line reading for each of the 60 day pillars combine, so the same occupation still gives different screens.

This test is entertainment. The perpetual-calendar part is a genuine computation on real solar-term data and the salary history is from the record, but the rules that turn eight characters into a Joseon job were invented here. Four Pillars astrology has no "Joseon success score".

And in Joseon, occupation was not decided by saju but by birth status and family — whether you could sit an examination at all was settled before you were born. A test that leaves the office of Chief State Councillor open to everybody is a thoroughly modern fantasy.