If you debuted as a K-pop idol,
what would your position be? 🎤

Saju (四柱, "four pillars") is Korea's classical system for reading a person from their birth moment — the same family of astrology known as BaZi or Four Pillars of Destiny elsewhere in East Asia. Your birth year, month, day and hour each become one pillar, and each pillar is written with two characters: a heavenly stem on top (ten of them: Gap, Eul, Byeong, Jeong, Mu, Gi, Gyeong, Sin, Im, Gye) and an earthly branch below (twelve of them, the zodiac animals from Rat to Pig). Four pillars, two characters each — eight characters in all, which is why Koreans call a person's fate their "palja" (eight characters). Pairing stems and branches in order produces a repeating cycle of sixty combinations, the famous sexagenary cycle.

The pillar for the day you were born is the day pillar, and its top character is the day master (ilgan, 日干). Classical saju treats this one character as "you," and the other seven characters as the environment around you. That is why this test can assign a position from nothing but a birth date: the position comes from the day master, and the day master is fixed the moment you know the date.

If you think about it, the idol-position concept runs on the same logic as saju. Seven members stand on one stage, but each has a different seat, and the leader's lines are not the main vocal's lines. Where saju looks for "you" among eight characters, an agency looks for your seat in the group inside a trainee's temperament. This page simply hands that casting meeting over to the almanac. If you want to see your actual eight characters, the manse-ryeok calculator (Korean) computes the full chart down to the minute of each solar term.

The ten heavenly stems are the five elements — Wood, Fire, Earth, Metal, Water — each split into a yang and a yin form. The same Wood behaves differently as yang Wood (Gap) and yin Wood (Eul). Below is how classical saju characterizes each day master, and which seat in the group this test cast it into. The same day master becomes a past life in the Past Life Test and a Joseon-era job in the Joseon Test — change the world, and the role changes.

Gap (甲) & Eul (乙) — the Wood day masters

Gap, yang Wood, is the great tree growing straight toward the sky — timber for pillars and beams. Its upward drive and chief-of-the-pack temperament make it the Leader: the one who books the practice room, gives the award-show speech, and calls the group meeting when the team wobbles.

Eul, yin Wood, is the flower and the vine. It doesn't push head-on; it climbs around the wall, and it survives wherever it's planted. That flexibility reads as the Variety Star — drop this member on any show and they come back with screen time and new fans for the whole group.

Byeong (丙) & Jeong (丁) — the Fire day masters

Byeong, yang Fire, is the midday sun: a presence that cannot be hidden and carries far. On stage that is the Main Dancer — the member the choreography videos can't stop following, the one the comments say "I only see them."

Jeong, yin Fire, is the lantern and the candle. Instead of spreading wide like the sun, it shines on one spot, long and deep. That's the Main Vocal — the 2 a.m. acoustic live that silences a whole arena with one high note.

Mu (戊) & Gi (己) — the Earth day masters

Mu, yang Earth, is the mountain and the levee: broad, thick, hard to shake. Not the flashiest seat, but the one that keeps the whole stage balanced — the Sub Vocal & Pillar of the group. When the members burn out, this is who they lean on.

Gi, yin Earth, is farm soil — the energy that grows and nurtures. It becomes the Fan Service Ace, the member who remembers every fan's username, runs every fansign into overtime, and single-handedly earns the fandom's favorite boast: "our group has the best personalities."

Gyeong (庚) & Sin (辛) — the Metal day masters

Gyeong, yang Metal, is raw iron, ore not yet refined — the kind that only gets harder when hammered. That's the Main Rapper: no trend-chasing, just a verse forged from raw stone that shifts the center of gravity of the whole track.

Sin, yin Metal, is the finished jewel — completed brilliance itself. It becomes the Visual: airport photos that make the news, face captures that circulate faster than the stage fancams.

Im (壬) & Gye (癸) — the Water day masters

Im, yang Water, is the sea and the great river: huge in scale, allergic to being boxed in. Vocals, dance, self-produced B-sides — that's the All-Rounder, the name that appears most often in the album credits.

Gye, yin Water, is rain, dew and night fog — the energy that seeps in silently. It becomes the Tone Fairy: eight bars in the second verse, and those eight bars refuse to leave your ears. The member behind every "skip to 3:12 and thank me later" comment.

There are 12 positions rather than 10 because two extra conditions sit on top of the day master. The first is gwaegang (魁罡) — six specific day pillars out of the sixty (Mu-jin, Gyeong-jin, Im-jin, Mu-sul, Gyeong-sul, Im-sul) that classical saju calls "the chief star," an extreme and forceful energy. Born on one of these six day pillars, you are cast as the Stage-Destroying Center regardless of your day master — the ace who seizes the stage on charisma alone — and the formula adds 9 bonus points to your stage-presence score. Center energy pushes your rank up on paper too. Across the 22,280 days from 1950 to 2010, exactly 10% — 2,228 days — qualify.

The second is the Agency CEO. This one is decided not by the day pillar but by the score itself: if your computed stage-presence score reaches 98 or higher, the test rules that you have too much star power to be an idol at all. You walk into the audition wearing a contestant number, and after a huddle, the judges pull out a chair for you at their table. Not one of the ninety-nine on stage — the one who casts the ninety-nine. Only 53 of the 22,280 days (about 0.2%) produce this, making it the rarest result in the test; if you drew the CEO, consider it a jackpot. Even a gwaegang day pillar becomes the CEO instead of the Center when the score clears 98 — you didn't just destroy the stage, you bought it.

The best on-team chemistry and dorm bickering partner pairings under your result aren't element theory — they're matched by how two positions would actually rub against each other in one group. The Leader's best chemistry is the quiet Pillar who backs them up, and their bickering partner is the Main Rapper writing verses through the team meeting; the Main Vocal harmonizes with the Tone Fairy and gets their moody midnight live crashed by the Variety Star, and so on.

The rank starts with a "stage-presence score," then flips it: rank = 100 − score. A score of 99 means final rank #1; a score of 1 means #99. This is the only test in the series where a low number is the good result, so read everything below in score terms. The rules are invented for this world — but they are the same rules for everyone.

1. Base score — your starting point depends on your day master's element: Wood 47, Fire 53, Earth 40, Metal 44, Water 49. The stage is a world of lights and heat, so Fire starts highest and steady Earth lowest. Earth day masters get the longevity talent instead — no reason to sulk about the starting line.

2. Relations with the other characters — the elements of your year, month and day branches (plus the hour branch, if you entered a birth time) are scored by their classical relation to your day master. Sik-sang (食傷), the energy you give birth to, is worth +8 — the biggest bonus. In saju it stands for speech, song and expression, everything that moves from inside you to the outside, and no character maps to stage presence better. Then jae-seong (wealth, the element you control) +3 — the pull that gathers fandom and ticket sales; bi-geop (peers, your own element) +2 — teamwork; gwan-seong (authority, the element that controls you) −3 — the model student who freezes on camera; and in-seong (the element that gives birth to you) −5. In-seong is the character of desks and deep thought, a liability on a stage that demands a new expression every three seconds. For contrast, the Past Life Test gives that same in-seong its maximum +7. Best asset for past-life memory, worst for stage instincts — the same character flips signs when the world changes.

3. Positional weights — the month branch is weighted ×1.8, the day branch ×1.2, the hour branch ×0.9, the year branch ×0.7. The month branch is the season of your birth and, in saju, the seat of your youth — and idol careers are bets placed on youth, so the month weighs most here. The year branch, the ancestral seat, weighs least for the same reason: survival shows don't ask about your family.

4. Yang/yin and gwaegang — yang day masters (Gap, Byeong, Mu, Gyeong, Im) get +3; yin day masters (Eul, Jeong, Gi, Sin, Gye) get −2. Yang stems radiate outward — stage constitution. The six gwaegang day pillars above add another +9.

5. Scatter — with only the steps above, identical day pillars would bunch together. So the birth-date string is fed through a fixed hash function to produce two offsets, up to ±27 and ±6. These are not random numbers — they are computed from the date, so the same date always gets the same offsets.

Finally, anything above 93 points is compressed to 0.45×, and anything below 8 is halved, clamping the score into 1–99. The top is squeezed harder because 98+ triggers the CEO verdict — the threshold is meant to stay rare. Subtract the score from 100 and you have your final rank. Run over every date from 1950 to 2010, the mean rank is #48.3 and the median #48, and both extremes — #1 and #99 — genuinely occur.

The "top N% of all contestants" on your result screen is not a comparison with other people who took this test. Your input never leaves the browser, so there would be no way to build one. Instead, a precomputed percentile table ships inside this page.

Here's how it was built. For every one of the 22,280 days from January 1, 1950 to December 31, 2010, the final rank was computed with birth time unknown. Then for each rank from #1 to #99, we counted what share of all dates (in permille) lands at that rank or better, and stored the 99 numbers. Your result screen just looks your rank up in that table. Since a smaller rank number is the better result in this test, a smaller number means a higher "top N%."

A few reference points: final rank #48 sits right at the median; 8.9% of all dates make the top 20, 2.7% the top 10, 1% the top 5. Drop below the top 50% — rank numbers greater than 50 — and the badge turns violet and flips into "top N% comeback potential." The lower half of the leaderboard is classified as the slow-burn comeback type that flips the charts three years after debut, so on that side, the bigger your rank number, the higher your comeback-potential percentile. Either way, you have something to brag about.

No random function is used anywhere in producing your result. Every value on the screen is computed from your birth date (and the optional birth time).

The sequence: your birth date is converted to a running day number, and its remainder mod 60 fixes the day pillar — the sexagenary cycle repeats every sixty days without exception. The year and month pillars are trickier. In saju, the year changes not on January 1 and not on Lunar New Year but at ipchun, the "start of spring" solar term, and the month rolls over at each of the twelve major solar terms. This page embeds a table of solar-term times, minute-precise, from 1900 onward — so for someone born in early February, it checks the clock, not just the calendar, to decide whether their year pillar is still the old year or already the new one.

Apply the formula above to the resulting eight (or six, without a birth time) characters and the score falls out; the final scatter offsets also come from a hash of the date string. The upshot: any day, any device, the same birthday produces the same position and the same rank. Which is exactly what you need if racking your rank against your friends is going to mean anything.

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

No — the input expects the solar (Gregorian) date. If you only know a lunar birthday, convert it to a solar date first (the Korean lunar–solar converter can do it). The almanac math runs on solar terms — the sun's position — not lunar dates, so feeding it a lunar date shifts the whole chart by up to a month.

Does not knowing my birth time change the result?

The position usually stays put: it's decided by the day pillar, and the day pillar depends only on the date. The rank is what moves. Enter a time and the hour branch joins the formula at ×0.9 weight, and the hash input that generates the scatter changes too. In practice the rank shifts by about 18 places on average with versus without a time. Leave it blank and noon is used as the representative time. The exception is the Agency CEO: the birth time can push a score across the 98-point threshold, so on some dates the CEO verdict comes and goes with the hour.

Another saju calculator gives me a different chart

This test computes with exactly one convention and no options. Birth time is taken only as one of twelve two-hour branches, using each slot's midpoint; there is no 30-minute standard-time correction and no late-Rat-hour school setting (whether 11 p.m.+ counts as the next day's pillar). The day pillar is fixed by the date alone, regardless of time. So if you were born around 11 p.m. or on the day of a solar term, a full-featured almanac may disagree. For a boundary-accurate chart use the manse-ryeok calculator (Korean) — it applies term times to the minute and lets you toggle both conventions.

My rank came out way at the back (a big number)

The items that push a rank backward are in-seong (the element that gives birth to your day master, −5 per character) and gwan-seong (the element that controls it, −3). The more thoughtful and rule-abiding the chart, the worse it fares in front of survival-show cameras — that's the setting. But a back-row rank on this scale is not elimination. As debut-survival history keeps proving, the finale leaderboard and the charts three years later are different questions. From #51 down you're classified as the slow-burn comeback type — the one whose old fancam rides the algorithm three years post-debut and flips the charts — and your badge flips to "top N% comeback potential" accordingly.

Does the share link contain my birthday?

No. The link carries a single number that packs exactly four display values: position id, final rank, top %, and day-pillar index. Your birth date and time are not in it and cannot be reverse-engineered from it. Whoever opens your link sees only your result screen.

I'm preparing for a real audition. Should I factor this in?

Please don't. This test has zero connection to real auditions, casting or aptitude. The rank and position are just numbers from the formula published above, and no agency casts trainees by almanac (probably). The almanac part itself is real, though — the day pillar on your screen is genuine calendar data. What an audition needs is a practice room, not a birth chart; what this page guarantees is only the fun of racking ranks with friends between practice sessions.

If you've read this far you've guessed: this is entertainment content. The almanac layer is a real computation over real solar-term data, but every rule that turns eight characters into idol positions and survival ranks was invented by this page. There is no "stage-presence score" in classical saju, and no school of it computes debut rankings. Results have nothing to do with real auditions, casting, aptitude or career choices.

One more thing: there are no losers among these 12 positions. Leader, Tone Fairy or CEO — every seat is one a group can't function without, and even #99 is not elimination but episode one of a comeback arc. That's what a debut evaluation is for — nobody shares a report card that says "neither pass nor fail." If the saju side hooked you, the manse-ryeok calculator (Korean) will show you your actual eight characters.