The round nail installed on the gate is called a doornail. Its original use was actually to reinforce the gate. Because we know that ancient construction technology is limited, there is no way to build too wide wood. Therefore, a door is often a few boards put together, and it is easy to spread out after a long time. Therefore, in order to avoid this phenomenon, people put wooden belts in the boards and then nail them to make the doors stronger.
Then in the Ming and Qing Dynasties, some people will use copper nails on the doors when they are rich, and some people will slide gold on the copper nails. It can be seen that the procedures corresponding to golden yellow and red doors are particularly beautiful. At this time, the door tripod has a decorative significance and plays a role in beautifying the door leaf.
Before the Qing dynasty, the number of nails was actually not specified, so you could use as many as you wanted. However, in the Qing dynasty, the number and arrangement of doornails were clearly stipulated, and the wrong use would be punished. At this time, the doornail also represents the level.
The Forbidden City was called the Forbidden City in Qing Dynasty, where the emperor lived. Therefore, the gate of the Forbidden City adopts the highest grade, with 9 rows and 9 columns, totaling 8 1 doornail. Why are there 9 rows and 9 columns here? Because nine is the pole of yang number, but the biggest one among poplars represents the supremacy of the emperor.
The number and arrangement of doornails in Qing dynasty were very strict and meticulous, and princes and county kings were waiting. The materials and quantity used in luxury houses are clearly defined. If you use it wrong, you will be punished.