Feng Shui is placed in Li Shizhen.
Superstition holds that mirrors were used to ward off evil spirits in ancient times. Li Shizhen, a great doctor in Ming Dynasty, said, "An ancient mirror is like Gu Jian. If there is a god, it can ward off evil spirits. Anyone should hang a big mirror to avoid evil spirits. " The "God" here can be understood as "Qi" and "Information". In ancient times, many buildings were hung with mirrors. These mirrors have little effect on reflecting the scenery and are mainly used as "mirrors". When installing a mirror indoors, pay attention to the position of the mirror, and be careful not to face the bed and table. If a mirror is facing the table and bed, part of the anger of the host will be reflected, which will affect your health. At night, the sun is weak, and I am afraid that the mirror will face the bed. Therefore, the mirror on the dresser, the mirror on the wardrobe and even the mirror hanging on the wall at home should not face the desk or the bed. If it really can't be opened, you can ignore it. When writing and sleeping, it is more auspicious to hang a thick door curtain and post a picture of gossip or symbols on it.
In addition, in the past, a mirror was hung above the door because some feng shui masters thought that the role of the mirror was to "wash away evil spirits", that is, to reflect away evil spirits that rushed straight over.
So many people like to hang a mirror on the door, so that Sha Qi can't get in. But if there is a house opposite, don't hang it up at last, otherwise it will be immoral.