The short answer
The clearest way to use a kua number with a car is colour. Pick a colour that matches your kua number’s element. Traditional sources say much less about seat position or driving direction, so the practical points below are suggestions, not established rules.
Colour by element
Each kua number has an element, and the colours below traditionally suit it:
| Kua number | Element | Colours that suit |
|---|---|---|
| 1 | Water | Black, blue |
| 2 and 8 | Earth | Yellow, ochre, beige, brown |
| 3 and 4 | Wood | Greens |
| 6 and 7 | Metal | White, silver, grey, gold |
| 9 | Fire | Red and related warm colours |
For kua 6 and 7, many practitioners suggest limiting strong red, because fire is said to control metal. For kua 1, many suggest keeping earth tones to a minimum, because earth is said to control water.
If you are not sure of your number, use how to find your kua. The kua number guide has the full chart.
Success colour or family colour
Some sources suggest choosing one colour for a car you use for business, and another for a car that is mainly for family use. Both colours come from your kua number, so you can pick the one that fits how you use the car.
Seat and driving direction
The Eight Mansions tradition is built around rooms, desks and beds, where a person sits or sleeps for long periods. The sources we checked do not describe a best seat for each kua number, and a moving car does not sit still in one direction.
A practical version is to use your favourable sectors for the places where you sit still for long periods, such as your desk and your bed. The office desk guide explains how. For the car itself, treat seat position as a personal choice rather than a traditional rule.
For the wider system, see the Eight Mansions overview.
These are traditional ideas, not scientific findings. Use them as a way to choose a colour you like, not as a rule for buying a car.