East group and West group, and why they never overlap
Published 2026-08-20
In Eight Mansions (八宅, Ba Zhai), the eight Kua numbers fall into two blocks of four. Kua 1, 3, 4 and 9 are the East group, and their four favorable directions are North, South, East and Southeast. Kua 2, 6, 7 and 8 are the West group, and theirs are Southwest, West, Northwest and Northeast.
The two lists do not overlap. Every direction that is favorable for one group is one of the four unfavorable ones for the other, so there is no shared middle ground to compromise on.
The two lists, generated from the tables
Reading AUSPICIOUS and INAUSPICIOUS in src/lib/kua.ts for all eight numbers gives this:
| Group | Numbers | The four that suit you | The four that do not |
|---|---|---|---|
| East | 1, 3, 4, 9 | North, South, East, Southeast | Northeast, Southwest, West, Northwest |
| West | 2, 6, 7, 8 | Southwest, West, Northwest, Northeast | North, East, Southeast, South |
Everyone in a group has the same eight-way verdict. What changes from one number to the next inside a group is only the order — which of your four is called the strongest and which the quietest:
| Kua | Group | Sheng Chi | Tian Yi | Yan Nian | Fu Wei |
|---|---|---|---|---|---|
| 1 | East | Southeast | East | South | North |
| 3 | East | South | North | Southeast | East |
| 4 | East | North | South | East | Southeast |
| 9 | East | East | Southeast | North | South |
| 2 | West | Northeast | West | Northwest | Southwest |
| 6 | West | West | Northeast | Southwest | Northwest |
| 7 | West | Northwest | Southwest | Northeast | West |
| 8 | West | Southwest | Northwest | West | Northeast |
So two people in the same group are never in conflict about a room; they only disagree about which of their four shared directions comes first.
The split is not arbitrary
Each number belongs to a trigram, and each trigram has a seat direction: Kan sits North, Zhen East, Xun Southeast, Li South — those are the four East group seats. Kun sits Southwest, Dui West, Qian Northwest, Gen Northeast — the West group seats.
Compare that with the table above: your four favorable directions are exactly the four seats of your own group. The good and bad lists are not two hand-written lists that happen to be complements; they come out of the trigram arithmetic that way.
The consequence nobody mentions: square rooms
A headboard flat against a wall in a room square to the compass points at one of four directions — North, East, South or West. The four diagonals are unreachable. That lands very unevenly across the two groups, and it is arithmetic rather than opinion:
| Group | Cardinal directions among your four | Reachable in a square room |
|---|---|---|
| East (1, 3, 4, 9) | three of four | three of four |
| West (2, 6, 7, 8) | one of four (West) | one of four |
Every West group number has exactly one cardinal favorable direction, and it is West for all four of them. So if you are West group and the west wall of your bedroom holds the window or the door, no bed position gives you both a favorable direction and a solid wall behind your head. Which direction should the head of your bed face goes into what practitioners do at that point.
A desk is looser, because you can either face a wall or back onto it, so each wall reaches two directions. It still cannot reach a diagonal in a square room. The direction that counts at a desk is the one you are looking in once you sit down: pushed against the north wall looking at it you face north, and with your back to that same wall you face south. See the desk direction tool.
Same birth year, different group
Because Eight Mansions uses two formulas, a man and a woman born in the same year often land in
different groups. Two examples from kuaNumber:
| Birth year | Men | Women |
|---|---|---|
| 1985 | 6, West group | 9, East group |
| 2004 | 2, West group | 1, East group |
This is the usual reason a couple finds their lists have no direction in common. There is no arithmetic inside Eight Mansions that resolves it — no average, no third list. The Kua number calculator is meant to be run twice, once per person, and the disagreement is a real result, not a bug to fix.
Houses have groups too, and it is a different question
The same eight-fold split applies to buildings, but through a different input. In src/lib/house.ts a
house takes its number from the direction it sits, which is the opposite of the direction it faces. A
house sitting North is a Kan house and East group; a house sitting Northeast is a Gen house and West
group.
Your group and the house’s group are two separate questions and neither overrides the other. Yours answers which way you should face. The house’s answers which sectors of the floor plan are which. A tool that folds them into one verdict — “you are an East group person so you need an East group house” — is adding a rule the arithmetic does not contain.
What the label does not mean
East group and West group are not personality types, and they are not about the part of the country you live in. They are the two halves of a compass classification, and the tradition attaches themes to the directions inside them. Eight Mansions names a direction favorable or unfavorable; it does not predict anything measurable, and neither do we. See method and assumptions for what is computed here and where the site stops.