China traditional architectural culture: why should there be a threshold for doors?

The threshold, also known as the threshold or railing, lies across the door, stepping forward and backward, giving people a feeling of being at home. It is the boundary between the inner area and the outer area. It should be said that people now live at home, and the threshold is not so symbolic. It is common to go in and out and cross the threshold. However, the previous understanding of the threshold was very unusual, and there were many stresses. First of all, the threshold has the function of shielding dirt and avoiding evil spirits. There is a threshold across the door, which symbolizes erecting a wall to keep out all bad things, especially those ghosts, so as to ensure the safety and happiness of the family.

There are two kinds of thresholds: fixed thresholds and movable thresholds. Generally, it is a fixed threshold, and some large families also have thresholds for activities at any time, which is convenient for getting in and out of cars and horses. According to the custom of old Beijingers, when seeing off guests, they must be sent outside the threshold. If you come on horseback and in a sedan chair, you should watch the guests get on the sedan chair at once. If you come on foot, you should see the guests leave. If you just send the guests out of the door without crossing the threshold, it is disrespectful to the guests and regarded as impolite. There used to be a custom of not stepping on the threshold, but you can sit without stepping on it. In the past, children were ignorant and often played on the threshold. Adults will immediately stop when they see it, saying that the threshold is the god to protect the family and cannot be stepped on casually.