Generally speaking, it refers to the short concave-convex wall on the city wall, and also refers to the fact that Quyi actors sing a few rhyming lyrics word by word. On the outside of the top of the city wall, in the direction of meeting the enemy, there is a crib more than two meters high, which is used by combatants to cover themselves when watching and shooting at the enemy.
Start with the floor on the wall, build by laying bricks or stones to the height of the human chest, and then start to build the crib. The mouth of a crib is generally made into a concave-convex shape. There is a small square hole in the upper part of the crib, namely _ Wang Dong.
_ The bricks on the left and right sides of Wang Dong are splayed inside and outside, which is convenient for observing the enemy and difficult to be shot by the enemy's arrows. There is a small square hole below, which is the perforation of the bow and arrow. The bottom of the perforation is inclined downward, which is convenient for shooting the enemy at the gate.
2. Watchtower
They are similar in shape and have their own characteristics, including wall platforms for patrol and sentry duty, and enemy platforms on the upper and lower floors. The upper floor is surrounded by cribs and shooting holes, and the lower floor is a house for soldiers to stay and store materials. The distance of the fortress depends on the mountain and terrain.
They are all masonry structures, and the tops of the first and second floors are made of many arches, with ladders up and down. There are shooting ports, observation ports and water spouts on both floors, and there is a crib upstairs. The platform protrudes from the wall and closes the wall in the platform.
Extended data:
Building method
The defense engineering building of the Great Wall has accumulated rich experience in the construction process of more than two thousand years.
First of all, in terms of layout, when Qin Shihuang built the Great Wall in Wan Li, he summarized the important experience of "blocking roads because of dangerous terrain", and then Sima Qian wrote in Historical Records. After that, every dynasty built the Great Wall according to this principle, which became an important basis for military protection.
All the passes in Guancheng are built between two high mountains and canyons, or at the bend of a river, or where they will pass through the plain, which can not only control the danger, but also save manpower and material resources, and achieve the effect of "one person guards it, and ten thousand people can't force it". Building castles or beacon towers in dangerous places is also an option.