What are the twelve life stages?

They are the twelve names — 장생, 목욕, 관대, 건록, 제왕, 쇠, 병, 사, 묘, 절, 태, 양 — that Bokki prints under each of the four pillars in your 만세력 chart. Each one is a position on a twelve-step circle rather than an entry in a lookup table. Your day stem fixes where the circle starts, and you count round the twelve branches from there to whichever branch you are asking about.

How is the stage actually calculated?

Every one of the ten stems has exactly one branch where its 장생 is fixed — 甲 at 亥, 丙 at 寅, 戊 at 寅, 庚 at 巳, 壬 at 申, 乙 at 午, 丁 at 酉, 己 at 酉, 辛 at 子, 癸 at 卯. Start at that branch and count round the twelve branches to the branch you are reading. Yang stems count forward, yin stems count backward. That is the whole calculation; there is no second table and no random element.

Why does 장생 come up more often than 건록?

Because the ten stems use only eight starting branches. 戊 shares 丙's 寅 and 己 shares 丁's 酉 — the traditional rule that Earth follows Fire. We counted all sixty possible day pillars: 장생, 관대, 제왕, 병, 묘 and 태 each land on six of them, while 목욕, 건록, 쇠, 사, 절 and 양 each land on four, a ratio of 1.5 to 1. On 21,900 real dates the same split came out as 2,190 against 1,460. Give 戊 and 己 their own non-overlapping starting branches and the twelve immediately come out at five each, which is how we confirmed the cause instead of guessing it.

Why does another site show a different stage for my day pillar?

Most likely because it follows the other school. Bokki counts yin stems backward from their own 장생; the other convention in circulation has a yin stem share its yang partner's 장생 and count forward. We counted the difference: thirty of the sixty day pillars come out differently — every yin-stem pillar, with none agreeing by chance — so half of all people read a different word. For a 21 July 1993 birth the day pillar 癸卯 is 장생 in our engine and 사 under the other convention. Neither engine is broken; they are two documented conventions.

What if I don't know my birth time?

Then the hour pillar has no branch, so no stage is printed under that column — the space is left empty. We would rather show a gap than guess a time and hand you a word that was never calculated. The year, month and day columns are unaffected and still show their stages.

What is 십이운성 (the twelve life stages)?

Q: Does 사 or 묘 mean something bad about my health?

No. These are the names of positions on a circle, sitting in its second half the way autumn sits in the second half of a year. Bokki does not read them as statements about your health or about the length of a life, does not score or rank them, and does not call any stage lucky or unlucky. There is no such reading anywhere in our code.

A position counted round a circle, not a name looked up in a table — and two things we found when we counted our own chart.

The short answer

When you put a birth date into Bokki, the 만세력 chart on the home screen prints one extra word under each of the four pillars: 장생, 목욕, 관대, 건록, 제왕, 쇠, 병, 사, 묘, 절, 태, or 양. Those twelve are the 십이운성, the twelve life stages, and they are usually presented as a table you look things up in. They are not a table. Each one is a position on a twelve-step circle, and the position is counted from two things you already have: your day stem, the 일간, which is the single character that stands for you; and the branch sitting at the bottom of whichever column you are reading. Every one of the ten stems has exactly one branch where its 장생 — its first stage, the beginning — is fixed. You start there and count round the twelve branches until you reach the branch you are asking about. Yang stems count forward. Yin stems count backward. That is the entire rule, and it is why the same branch means one stage for one person and a different stage for the next.

Two people, followed the whole way round

Take a birth of 15 May 1990 at 14:30 in Seoul. The day stem comes out 庚, which is a yang stem, and 庚 has its 장생 at 巳, so we start at 巳 and count forward. Reading the four columns the way the chart prints them, the year branch 午 lands on 목욕, the month branch 巳 is the starting point itself and so lands on 장생, the day branch 辰 lands on 양, and the hour branch 未 lands on 관대. Now take a birth of 21 July 1993 at 09:10 in Seoul. The day stem is 癸, a yin stem, whose 장생 sits at 卯 — and because it is yin we count backward from there. The year branch 酉 lands on 병, the month branch 未 on 묘, the day branch 卯 is the starting point and so lands on 장생, and the hour branch 辰 on 양. Written out in full for one stem each way: 甲 counting forward gives 子 목욕, 丑 관대, 寅 건록, 卯 제왕, 辰 쇠, 巳 병, 午 사, 未 묘, 申 절, 酉 태, 戌 양, 亥 장생. 癸 counting backward gives 子 건록, 丑 관대, 寅 목욕, 卯 장생, 辰 양, 巳 태, 午 절, 未 묘, 申 사, 酉 병, 戌 쇠, 亥 제왕.

The twelve do not come up equally often

Here is something we did not expect until we counted. Because a day pillar pairs a stem with a branch of the same polarity, there are exactly sixty possible day pillars, and the calendar cycles through all sixty evenly — we checked that too, on 21,900 real dates from 1 January 1960, which is sixty years and therefore a whole number of cycles: each of the sixty day pillars appeared exactly 365 times, dead level. So if the twelve stages were spread evenly across those sixty pillars you would expect five each. They are not spread evenly. Six of them — 장생, 관대, 제왕, 병, 묘, 태 — appear six times out of sixty, and the other six — 목욕, 건록, 쇠, 사, 절, 양 — appear four times. One group is 1.5 times as common as the other, and on the 21,900 dates that came out as 2,190 against 1,460, exactly 365 times the sixty-pillar counts. The cause is not a flaw in any shuffle, because there is no shuffle here; nothing is drawn. It is that the ten stems do not use ten different starting branches. They use eight. 戊 takes its 장생 at 寅, the same branch 丙 uses, and 己 takes its at 酉, the same branch 丁 uses — the traditional rule that Earth follows Fire. We tested that this really is the cause rather than guessing: give 戊 and 己 their own non-overlapping starting branches, change nothing else, and the twelve stages immediately come out at exactly five each, perfectly level. So the lopsidedness you see is the arithmetic shadow of a rule about Earth and Fire, cast onto a count nobody usually performs.

Where the schools disagree, and which side we are on

The rule that yin stems count backward is not the only rule in circulation. Another convention, the one you will meet on a good many other charts, has a yin stem share its yang partner's 장생 and count forward alongside it, so that 癸 would begin where 壬 begins rather than at its own branch. Bokki uses the backward rule — that is what our engine has counted from the start — and we would rather name the choice out loud than let it stand there looking like the only possibility. It matters more than it sounds. We counted: of the sixty day pillars, thirty come out differently under the other convention — that is every single yin-stem pillar, with not one of them happening to agree by chance — so exactly half of all people would read a different word under their own day column. Our second worked example is the sharpest version of that. For the 1993 birth above, the day column is 癸卯, which our engine calls 장생, the first stage, the beginning. Under the other convention the very same column is 사, the stage sitting almost opposite it on the circle. Same person, same chart, same two characters, and the two schools land on opposite ends. If you compare Bokki against another site and find this word different, that is what you are looking at, and neither engine is broken.

What we don't calculate

The stage names are positions on a circle, not descriptions of a body. 병, 사, 묘 and 절 sit in the second half of that circle the way autumn sits in the second half of a year, and we do not read them as statements about your health or about the length of a life — there is no such reading anywhere in our code, and we are not going to add one. We do not put a number on the stage either: no stage is scored, ranked, or called lucky, and you will not find a percentage attached to it. We do not decide whether a chart is strong or weak from the stage alone; that judgement uses the whole pillar set, and a single word under one column is not enough to carry it. If you do not tell us your birth time, the hour column has no branch at all, so no stage is printed there — we leave the space empty rather than guess a time and hand you a word that was never calculated. And we do not tell you that the backward-counting school is the correct one and the other is wrong. We tell you which one produced the word on your screen.

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