House-building year check
Check whether your age falls under Kim Lâu, Hoang Ốc or Tam Tai in the year you plan to build, with the arithmetic shown so you can verify it. Only your birth year is needed; the next ten years are scanned for a clear one, and age-borrowing is explained in case you need it.
Where this comes from
The three hazards Kim Lâu, Hoang Ốc and Tam Tai are folk knowledge, computed from the lunar age of the person in whose name the house is built; each is shown with its arithmetic. Schools differ: some look only at Kim Lâu, and some texts compute Hoang Ốc by adding the two digits; the page uses the traditional count.
Day and month are optional, used only to convert to the lunar year: anyone born between early January and about 20 February usually still belongs to the previous year.
This tool is part of Feng shui. See every tool and article on Feng shui.
Classical allusion
“Cư trần lạc đạo thả tuỳ duyên, cơ tắc xan hề khốn tắc miên.”
Translation: Dwell in the world, delight in the Way, and follow what comes: eat when hungry, sleep when tired.
Trần Nhân Tông · Rhapsody on Dwelling in the World and Delighting in the Way
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Best day for a purpose
The building year is settled. Day picker by task chooses dates for groundbreaking, roofing and moving in by the owner's age.
Open Best day for a purposeWhat no one has shown
No study has shown that building in a hazard year leads to anything. The result uses the lunar year of the birth date, so everyone born in the same lunar year gets the same result.
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What are Kim Lâu, Hoang Ốc and Tam Tai, and how are they worked out?
Before breaking ground, Vietnamese custom checks three taboos for the person named as the house owner: Kim Lâu, Hoang Ốc and Tam Tai. All three use lunar age (tuổi mụ), the building year minus the birth year plus one. Someone born in 1990 is 37 in 2026 by this count.
Kim Lâu divides the lunar age by 9: a remainder of 1, 3, 6 or 8 means the taboo applies. Each has its own name: 1 is Kim Lâu Thân (the owner), 3 is Kim Lâu Thê (the wife), 6 is Kim Lâu Tử (the children), 8 is Kim Lâu Lục Súc (livestock).
Hoang Ốc counts through six positions: Nhất Cát, Nhì Nghi, Tam Địa Sát, Tứ Tấn Tài, Ngũ Thọ Tử, Lục Hoang Ốc. Age 10 starts at Nhất Cát, 20 at Nhì Nghi, 30 at Tam Địa Sát, and you count on by the units digit. Nhất Cát, Nhì Nghi and Tứ Tấn Tài are good; the other three are bad.
Tam Tai goes by the Tam Hợp group of the birth year, and each group meets it for three years in a row. Thân, Tý and Thìn meet it in Dần, Mão and Thìn years; Dần, Ngọ and Tuất in Thân, Dậu and Tuất years; Tỵ, Dậu and Sửu in Hợi, Tý and Sửu years; Hợi, Mão and Mùi in Tỵ, Ngọ and Mùi years.
The birth year here is the lunar year. If you were born in January or early February, add your birth day and month, as you may still belong to the previous lunar year. Schools differ: some read only Kim Lâu, and some texts count Hoang Ốc with a digit-sum shortcut; the site uses the traditional count above. A year clear of all three is not easy to find, and in practice people often go ahead when only one applies, borrowing an age for the rituals.
| Taboo | Method | Applies when |
|---|---|---|
| Kim Lâu | Lunar age divided by 9, take the remainder | Remainder 1, 3, 6 or 8 |
| Hoang Ốc | Count 6 positions by tens then units | Lands on Tam Địa Sát, Ngũ Thọ Tử or Lục Hoang Ốc |
| Tam Tai | By the Tam Hợp trine of the birth branch | The year falls in the group's three Tam Tai branches |
Frequently asked questions
Do I need my birth date and hour?
The three taboos use only the birth year. The day and month matter only if you were born before Tết, so the year can be converted to the right lunar year. The birth hour is not used.
What is lunar age and how is it counted?
It is the building year minus the birth year plus one. Someone born in 1990 is 37 in 2026 by this count, even before their birthday.
Can I still build if one of the taboos applies?
This is folk belief, not a prohibition. When only one applies, many families still build, usually borrowing an age for the rituals.
What is age-borrowing, and is there legal risk?
It means asking someone clear of all three taboos that year to perform the groundbreaking and roof-raising rites in the owner's place, with a symbolic bill of sale that is bought back afterwards. That paper is ritual only and has no legal force. Never use a real property transfer for this rite.
Is Kim Lâu different for women?
Some texts say so, but the tables used for house building all read the age of the person named as owner, regardless of gender. Gender is used only for the house direction under Eight Mansions, which does differ for men and women.
Once I have a year, what else is there to choose?
The three taboos apply to the year only. After that come the month, the day and hour for breaking ground, and the house direction. The land, the surroundings and the layout have to be judged on site.
Why is the arithmetic shown?
So you can check it yourself. Each taboo shows the division, the remainder or the count, so you can redo it on paper and compare with tables elsewhere.
Public API, returns JSON, no sign-in: GET https://api.nhatnguyet.org/api/v1/calc/xem-tuoi-lam-nha?namSinh=1990&namXem=2027