First, the role of the threshold Let's put aside feudal superstitions and talk about the role of the threshold from the manufacturing aspect. The original intention of ancient people to design doors was to close houses and prevent thieves from appearing. Therefore, no gap can be left at the top of the gate, but if the bottom of the gate is in contact with the ground. Then it will cause the noise of opening and closing the door and wear the bottom of the door. In this way, there is a contradiction. The door should be closed, but it can't directly act on the ground. Therefore, people invented the threshold, and let the closed door contact with the threshold and door frame to form a completely closed space, which is in line with the original intention of the ancients.
Second, the significance of the threshold From the perspective of feudal superstition, the ancients believed that having a threshold at home had the function of gathering wealth and avoiding ghosts and gods. If there is a gap in the middle, it will affect the fate of the whole house and the owner. The threshold can just make up for the money leaked by the owner, so ancient people will like to build a high threshold. In fact, we modern people, especially businessmen who do business, often ask about Feng Shui when buying a house, paying special attention to the influence of this fate. It can also be seen that people's success in real life often has some luck in it, so businessmen are more dependent on wealth.
Third, the ancients had infinite wisdom because there was a gap between the gate and the ground. At first glance, it's really ugly, and the threshold plays an aesthetic role. Moreover, in the eyes of ancient people, the gate has a status symbol. If the pattern engraved on the door is more beautiful, the identity of the representative will be more expensive. Therefore, the ancient nobles even designed the threshold wonderfully, just to bless their children to thrive and thrive.