Nine Star Ki — 本命星 and 月命星, turned at 立春
Works out the two nine-star numbers from a birth date with every step shown: the digit sum, the subtraction from eleven, the 立春 and 節入り instants to the minute, and the 洛書 magic square shifted into a year plate. It prints no personality reading and no lucky direction, and says at length why not.
Two numbers from a birth date: 本命星 from the year, 月命星 from the 節月. Both are small arithmetic on a magic square, and both turn on boundaries that are not calendar boundaries — the year at 立春, the month at each 節入り, computed here to the minute from the same solar-longitude solver behind this site’s 24절기 table. What the numbers are supposed to mean, and above all which direction they make lucky, is not on this page, and the page explains at length why not.
Two numbers from a birth date and a magic square. The arithmetic is exact and every step of it is on this page; what a star is supposed to say about a person, and which direction it makes lucky, is not here, because those sentences were written in the last hundred years by people who are still in copyright.
Only matters within a day of a boundary. With no time given the reading takes the earlier side, which is the conservative answer.
本命星 — the year star
一白水星
いっぱくすいせい
1990 reduces to 1; 11 − 1 = 10, wrapped into 1–9 → 一白水星
The 気学 year turns at 立春, which in 1990 fell on 2/4 at 11:14 JST. This birth is in the year that began then.
月命星 — the month star
五黄土星
ごおうどせい
The 節月 opened at 立夏 — 5/6 03:36 JST — and runs under the branch 巳.
The year’s branch is 午, so this year’s months start at 八白土星 and count down one per 節.
The 年盤 of that year
South is at the top and north at the bottom, the way these are always drawn. The plate is the 洛書 square with every palace shifted by the same amount so the year’s star lands in the middle — which is why the numbers look as though they jump about when nothing has actually moved.
The 月盤 of that month
The twelve 節月 of that 気学 year
| 節 | Opens | Branch | Star |
|---|---|---|---|
| 立春 | 1990-02-04 11:14 | 寅 | 八白土星 |
| 驚蟄 | 1990-03-06 05:19 | 卯 | 七赤金星 |
| 淸明 | 1990-04-05 10:13 | 辰 | 六白金星 |
| 立夏 | 1990-05-06 03:36 | 巳 | 五黄土星 |
| 芒種 | 1990-06-06 07:46 | 午 | 四緑木星 |
| 小暑 | 1990-07-07 18:00 | 未 | 三碧木星 |
| 立秋 | 1990-08-08 03:45 | 申 | 二黒土星 |
| 白露 | 1990-09-08 06:37 | 酉 | 一白水星 |
| 寒露 | 1990-10-08 22:14 | 戌 | 九紫火星 |
| 立冬 | 1990-11-08 01:24 | 亥 | 八白土星 |
| 大雪 | 1990-12-07 18:14 | 子 | 七赤金星 |
| 小寒 | 1991-01-06 05:28 | 丑 | 六白金星 |
The plate for any year
一白水星 is in the centre palace of that year’s plate. That is where the arithmetic puts it, and this page says nothing about what it means.
5 → south · opposite north
The nine stars and their labels
| Star | Element | Trigram | Home |
|---|---|---|---|
| 一白水星 | 水 | 坎 | north |
| 二黒土星 | 土 | 坤 | south-west |
| 三碧木星 | 木 | 震 | east |
| 四緑木星 | 木 | 巽 | south-east |
| 五黄土星 | 土 | — | centre |
| 六白金星 | 金 | 乾 | north-west |
| 七赤金星 | 金 | 兌 | west |
| 八白土星 | 土 | 艮 | north-east |
| 九紫火星 | 火 | 離 | south |
What the nine stars are
A star is a number from 1 to 9 with four labels attached: a colour, one of the 五行, one of the eight trigrams of the 易経, and a compass point. Those labels are not modern. They are the 後天 arrangement of the trigrams laid over the 洛書 magic square, and the same table is in Chinese sources centuries before anyone in Japan called it 気学.
The square is the reason the arrangement feels arbitrary. There is exactly one way to fill a 3×3 grid with 1 to 9 so that every row, column and diagonal sums to 15 — up to turning it and flipping it — and this is it. The legend attaches it to 禹, who is said to have read the pattern off the shell of a turtle coming out of the river 洛, which is why it is called 洛書, the writing from the Luo.
五黄 has no trigram. There are eight trigrams and nine palaces, and the centre is not a direction, so the middle of the square is left over. Everything the tradition says about 五黄 being different in kind follows from that gap in the table rather than from anything in 五行 theory.
Where this particular system comes from
九星 as a body of folk cosmology is Chinese and old. 九星気学 as a named practice is not: 園田真次郎 (1876–1961) put it together in 1924, simplifying the 九星方鑑学 that was current in Japan at the time — the line of the Edo-period 家相 writer 松浦琴鶴 — into something a lay reader could work out for themselves. It spread from there, and it is now one of the most widely practised forms of divination in Japan.
That is a hundred years, not a thousand, and it matters for what can honestly be printed. The arithmetic Sonoda simplified is older than he is and is on this page. The readings he and his successors wrote are his and theirs, are in copyright, and are not.
Some 気学 writers date the system to 徳川家康’s adviser 天海, or further back. There is no evidence for that, and it is the same claim of concealed antiquity that attaches to most systems of this kind.
What this page will not tell you
- What your star says about your character. Those paragraphs exist in quantity — one per star, in every 気学 book and on every 気学 site — and every one of them was written in the last century by an author who is either alive or recently dead. There is no old text to quote instead, because before Sonoda nobody was assigning personalities to birth years in this form.
- Which directions are lucky for you. This is the largest part of 気学 by volume and the part the tool refuses hardest. The system names particular placements — 五黄殺, 暗剣殺, 本命殺, 歳破 — and attaches to them advice about which way to travel, when to move house, and which quarter of the compass to avoid in a given year. That advice is modern, it is under copyright, and no test of it has ever been published. The plate is on this page because the plate is arithmetic. What to do about it is not on this page at all.
- Whether two people’s stars go together. The 相性 tables are the same modern material in another arrangement, and this site does not print compatibility as a verdict or as a percentage anywhere.
- Your day star. This one is refused for a different and better reason: it is not determined. The 日家九星 runs up through 陽遁 and down through 陰遁, switching at the 甲子 day nearest each solstice, and because 360 days of alternation do not fill a year the sequence needs a 60-day correction every eleven or twelve years — 九星の閏. Schools place that correction differently, and disagree over 1916 against 1917, over the summer and the winter of 1928, over 2019 against 2020. A number with several published answers is not something a calculator should print one of.
The almanac these came out of was banned
略暦は歳徳・金神・日の善悪を始め、中下段掲載候不稽の説等増補致候儀一切相成らず候
“The abridged calendar shall on no account carry 歳徳, 金神, the good and bad of days, or any of the rest of that unfounded talk from the middle and lower registers.” — 太政官布告, 24 November 1872, following the decree that replaced the lunisolar calendar. 歳徳 is the year’s auspicious quarter and 金神 is a directional taboo: the two named prohibitions are directional fortune-telling of exactly this family.
Sources
- The 洛書 square, the 五行 and the 後天 trigram-and-direction assignment are the old Chinese correspondences and are reported as structure, not as fortune.
- 本命星 and 月命星 follow the two rules the Japanese reference works give — 11 minus the digital root of the year, and the 節家九星 table keyed on the year’s branch — and the tests reproduce that table in full.
- 立春 and the eleven other 節 come from this site’s own solar-longitude solver, the same one behind the 24절기 page, which is checked to the minute against 한국천문연구원’s published 절입시각. Japan’s standard meridian is 135°E, the same UTC+9.
- 園田真次郎 (1876–1961) assembled 九星気学 in 1924 out of the 九星方鑑学 then current in Japan. His books and his successors’ are in copyright and are not quoted here.
- The 1872 decrees are primary and out of copyright: 明治五年太政官布告第三百三十七号 and the 太政官布告 of 24 November 1872.
How to use it
Check which side of 立春 you were born on
The 気学 year does not start on 1 January. Someone born on 2 February belongs to the previous year’s star, and someone born on the day 立春 itself falls needs an hour to settle it — the page marks that case and asks for the time. Without a time it takes the earlier side, which is the conservative answer rather than a guess.
Follow the working, which is three lines
Sum the digits of the year until one digit is left, take 11 minus that, and wrap anything over 9 back round. For the month, the year’s branch picks one of three rows — 子・卯・午・酉 start at 八白, 丑・辰・未・戌 at 五黄, 寅・巳・申・亥 at 二黒 — and the star then counts down one per 節. Because lcm(9, 12) is 36, that whole month table repeats every three years.
Read the plate as a shifted square
The 3×3 grid is the 洛書 — the only arrangement of 1 to 9 whose rows, columns and diagonals all sum to 15 — with every palace shifted by the same amount so that the year’s star sits in the middle. South is at the top, as these are always drawn. The numbers look as though they scatter; nothing has moved except the whole square at once.
Common questions
What does my star say about me?
This page does not say, because there is nothing to quote. 九星気学 in its present form was put together by 園田真次郎 in 1924 out of the 九星方鑑学 then current in Japan; the personality readings are his and his successors’, they are a century old at most, and they are in copyright. There is no older text that assigns a character to a birth year in this form to quote instead. What the page gives you is the structure — the element, the trigram, the palace — which is genuinely old and is not a claim about you.
Where is the 吉方位 — the lucky direction?
Deliberately absent. It is the largest part of 気学 by volume and the part with the least behind it: the advice about which way to travel and when to move house is modern, is under copyright, and no test of it has ever been published. The plate is here because the plate is arithmetic; what to do about it is not. The page quotes instead the 1872 decree in which the Japanese government banned 歳徳 and 金神 — the year’s auspicious quarter and a directional taboo — from the almanac by name, as unfounded talk.
Why is there no day star?
Because it is not determined. The 日家九星 counts up through 陽遁 and down through 陰遁, turning at the 甲子 day nearest each solstice, and since 360 days of alternation do not fill a year it needs a 60-day correction — 九星の閏 — every eleven or twelve years. Schools put that correction in different places and disagree over 1916 against 1917, over the summer and the winter of 1928, over 2019 against 2020. A calculator should not pick one published answer out of several and print it without saying so, and saying so is most of what there would be to print.
Does this agree with the 사주 page about my year?
It has to, and a test holds it there. Both tools ask the same function which side of 立春 a date falls on, and that function reads the instant from the same 절기 solver that reproduces 한국천문연구원’s published 절입시각 to the minute. If a future change ever split the two, the test fails rather than the pages quietly disagreeing.
Feed it from
Next
These accept what this tool produces, so the result can go straight in.
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