There are many many feng shui websites that have articles on the bagua mirror and sha qi. A lot of it is a bit off target and may scare some people from feng shui. So, this post is to help people make their own judgment.
Sha qi is “killing” or “bad” qi or sometimes even called “negative” energy. Sha qi can be created from sharp objects or corners that point toward you. Roads and hills that are in alignment with your home, where the momentum of a car driving toward your home can also cause sha qi. See the diagram above. The three houses on the left are in a row. Cars will come directly toward the center home due to the road. This is considered sha qi. Also, the two homes on each corner of the road may cause sha qi to the center home because the corners of their roof line can form a sharp point that may be considered an “arrow” of sha qi. From this perspective, the middle home on the left has no chance!
Some recommended cures suggest placing a bagua mirror on the front door of the house to “deflect” this negative energy. So what is a bagua mirror. It is an eight sided frame with a mirror in the center. The mirror can be flat, concave or convex. A few websites suggest placing this mirror on the exterior beam above your front door to deflect sha qi. Others say use it to deflect anything. There are many different versions of cures. However, all that being said, this is a cultural practice, not a universally applicable feng shui solution. If you grew up believing this then it is understandable that you do this. It is part of your culture.
From a practical perspective, placing a mirror on the exterior of your home facing the road may not be a safe solution. You may blind the driver or if placed in a poor position, you can cause a fire. Mirrors can be dangerous too, so please be cautious. Also, the ancient Chinese didn’t have mirrors, instead they used bronze metal that created a reflection.
The best solution to deflect the energy that is coming toward your home this situation is to build a barrier of some form: a fence, a hedge or even a wall to protect you from the oncoming traffic. As far as the neighbor roof lines, they are so far away and inevitable, it’s best not to worry about something so far away and quite harmless. The best thing is not to get yourself too worked up on trivial matters that are not really causing any harm.
Feng shui is really about living in harmony with nature, to enjoy your environment and those around you. Good feng shui encourages good relationships with family and friends. Look at the big picture and try not to be too concerned about the little things that may give you unnecessary stress.