Choosing a home's direction by age: calculating the Eight Mansions life trigram and the limits to know

Feng shui is a traditional belief and cultural practice that many people consult when choosing a home; this article presents the common method so you can understand and cross-check it, and does not assert the result. Updated 23 October 2026.

Home direction by age is usually worked out with the Eight Mansions (Bát trạch) method: take the owner's birth year and gender to get a life trigram (cung phi), then match it against the eight directions. The result gives you 4 directions regarded as favourable and 4 to avoid. Below are the calculation, a lookup table and what else to weigh before deciding to buy.

1. What is a life trigram?

In Eight Mansions belief, each person corresponds to one of 8 trigrams (Khảm, Khôn, Chấn, Tốn, Càn, Đoài, Cấn, Ly). The eight trigrams fall into two groups:

• East Group (Đông tứ mệnh): Khảm, Chấn, Tốn, Ly.
• West Group (Tây tứ mệnh): Càn, Khôn, Cấn, Đoài.

Many sources say a person suits the directions of their own group: the East Group suits North, East, Southeast and South; the West Group suits West, Northwest, Southwest and Northeast.

2. How to work out the life trigram from birth year

The common method (per the life trigram guide on Batdongsan.com.vn, updated 16 February 2024): add the last two digits of the birth year, and if the sum is greater than 9, add again to reach one digit (call it a).

Gender	Born before 2000	Born from 2000
Male	10 − a	9 − a (if 0, take the Ly trigram)
Female	5 + a (if greater than 9, add the digits to one digit)	6 + a (if greater than 9, add the digits to one digit)

Look up the result number in the table: 1 Khảm, 2 Khôn, 3 Chấn, 4 Tốn, 5 central palace (male goes to Khôn, female goes to Cấn), 6 Càn, 7 Đoài, 8 Cấn, 9 Ly.

Example: a man born in 1985: 8 + 5 = 13, 1 + 3 = 4; 10 − 4 = 6, the Càn trigram (West Group). A woman born in 1990: 9 + 0 = 9; 5 + 9 = 14, 1 + 4 = 5, the central palace, which goes to Cấn for a woman (West Group).

You can see a table of examples for many birth years in the article How to work out your trigram and Five Elements (nạp âm).

3. The four good directions of each trigram

According to the common Eight Mansions table, the four good directions (Sinh khí / Life Force, Thiên y / Health, Diên niên / Longevity, Phục vị / Stability) of each trigram lie in the same East or West group:

Trigram	Sinh khí direction (regarded as the best)	Four good directions
Khảm	Southeast	Southeast, East, South, North
Ly	East	East, Southeast, North, South
Chấn	South	South, North, Southeast, East
Tốn	North	North, South, East, Southeast
Càn	West	West, Northeast, Southwest, Northwest
Khôn	Northeast	Northeast, West, Northwest, Southwest
Cấn	Southwest	Southwest, Northwest, West, Northeast
Đoài	Northwest	Northwest, Southwest, Northeast, West

The other four directions (the opposite group) are called the unfavourable directions: Tuyệt mệnh (Total Loss), Ngũ quỷ (Five Ghosts), Lục sát (Six Killings), Họa hại (Mishaps). The names are symbolic labels of the school; you need not take them literally, and in practice a home rarely faces exactly as the theory says.

4. How is home direction counted, and for whom?

• For whom: usually taken from the head of household. An advice article in Dau Tu Newspaper (Hoang Trieu Hai, 24 June 2017) says: if living with an older blood relative, use that person; if only a married couple, use the husband. Which person represents the household differs between sources; many families choose the person named on the purchase.
• Which direction counts: many people use the direction of the main door, some use the direction of the balcony / frontage. For apartments, the Dau Tu article suggests the ideal is that both the main door and the balcony lie in the favourable group, and notes that you should measure direction with a real compass, not rely on a phone compass.
• Birth-year cut-off: birth year is counted by the lunar calendar (people born in January–February of the solar calendar may belong to the previous year); some sources use the Start of Spring as the cut-off, others use Lunar New Year.

5. Limits of this method

• It is only one school. Eight Mansions works from the occupant's trigram; feng shui has many other schools (Xuan Kong, Luan Tou and so on) that give different conclusions. Dau Tu Newspaper also notes that Eight Mansions is not the only deciding factor.
• The formula varies by source. The wording and the birth-year cut-off differ; check at least two sources or ask someone knowledgeable.
• Homes with several occupants. Spouses often belong to different East / West groups. A common approach is to prioritise the main direction by the head of household, and arrange bedrooms, desks and the kitchen by individual.
• A direction that is good in theory may not be good for the climate. Homes in Vietnam are usually hot and glaring if they face West; Southeast and South catch cooler breezes. A building featured by VnExpress (7 June 2023) faces South, limits the area exposed to East and West, and adds wide eaves to stay cooler. Southwest / West-facing homes are still livable with a deep balcony, louvres, curtains and heat-insulating glass.

6. What if the apartment does not suit your direction?

An apartment's direction cannot be changed. There are three common ways to deal with it:

1. Put other criteria first. A project's legal status, location, price, schedule and the quality of the unit decide long-term value more than one direction.
2. Choose another unit in the same project. Each building usually has several directions; ask for the remaining units by main-door direction and balcony direction.
3. Adjust the inside. In feng shui belief, people place the bed, desk and stove to face a direction suited to their age even when the main door does not suit. This follows belief, and it is for you to weigh.

Choosing a unit: the order to look

1. Check the project's legal status (guide).
2. Look at real sun and wind in the afternoon, not just the drawings.
3. Cross-check direction by Eight Mansions if the family cares about it.
4. Work out total cost (costs on top of the sale price).

Note: feng shui is for reference only. When buying a home, give priority to clear legal status, construction quality, light and ventilation, and a price within your financial means. No direction guarantees luck or profit.

• Batdongsan.com.vn (wiki) — Cung phi là gì? Cách tính cung phi Bát trạch (male / female formulas, number–trigram table; updated 16 February 2024), accessed 23 October 2026.
• Dau Tu Newspaper — Hoang Trieu Hai, Tư vấn chọn nhà chung cư theo phong thủy: hướng và phương pháp tính mệnh trạch đơn giản, 24 June 2017.
• VnExpress — Ngôi nhà "đông ấm, hè mát", 7 June 2023.
• The table of East / West groups and the 4 good directions of each trigram: compiled from common Eight Mansions belief, not tied to a single source; the Dau Tu article numbers the trigram groups in a different way, so the table needs to be checked by someone knowledgeable.