It is "9". Because according to the compass pointing south, we add 9 up north and down south to get 9. The compass is 0 above 9, so the answer is 9.
The ancient Chinese believed that a person's aura is controlled by the aura of the universe. If a person is in harmony with the universe, it is auspicious, and if a person is not in harmony with the universe, it is a bad thing. Therefore, based on their experience, they put all the information at all levels in the universe, such as the stars in the sky, everything on the earth represented by the five elements, the heavenly stems and the earthly branches, etc., on the compass.
Feng Shui masters use the rotation of magnetic needles to find the most suitable location or time for a specific person or specific thing. Although the concept of "magnetic field" is not mentioned in Feng Shui, the coordination of the directions, orientations, and intervals between the circles on the compass implies the laws of "magnetic field".
Extended information:
Other brain teasers
1. What thing has no limbs and only a very lethal head?
Answer and analysis: Brick (literally, it has only one word "head". From a physical point of view, it does not have limbs, only one head. If you use it to hit people, it will cause damage. The force is definitely strong enough. )
2. Even if a knife is placed on your neck, you will not hold its hand tightly. What is it?
Answer and analysis: Cactus (Cactus is famous for being covered with thorns, and no matter who it is, no one will be happy to hold its hand tightly.)