The ancient city wall of Xi'an
The horse face in the ancient city wall is a kind of city defense facility, and the main purpose of its design is to enhance the defensive capacity of the city wall. The horse face protrudes at regular intervals from the city wall, and its plan is rectangular or semicircular. Its function is to eliminate dead spots under the castle and attack the enemy from three sides, making it difficult for the enemy to approach the city walls. In the era of cold weapons, the emergence of horse noodles was mainly a reflection of military needs, which provided the possibility of using troops and weapons in the most economical and reasonable way. The width of the horse surface is generally 12~20 meters, the surface of the protruding wall is 8~12 meters, and the spacing is generally 20~250 meters (generally 70 meters). In ancient times, in line with the record in the Song Dynasty rules "Guarding the City, Guarding the City": the old system of horse face is sixty steps to stand one, jumping out of the city without reducing two zhang, wide and narrow with the location is uncertain, looking at the corner of the city on both sides, and there are buildings on it.
The role of horse faces in ancient city walls is mainly reflected in three aspects:
First of all, the horse face helps to protect the walls of the city wall. As early as the Spring and Autumn Period and the Warring States Period, there were large cold weapons such as stone generators, which could emit large stones and were amazingly powerful, and if the city walls were not strong, they could easily be knocked down. The construction of horse faces on the wall can increase the thickness of the wall and prevent the city wall from being smashed out of holes by stones.
Secondly, the horse face can increase the defensive area of the city wall. The protruding horse face is equivalent to three more sides of the city wall, which can disperse the enemy number when the enemy is swarmed up, lengthen the battle line, and facilitate battle.
Finally, the horse face is also conducive to the formation of crossfire. In ancient times, when the two armies fought, the armies of both sides were divided into multiple units such as the front army, the rear army, the left and right wings, etc., and the protruding wall of the horse face could increase the sight of both sides during the battle, and the soldiers could not only shoot in a straight line when fighting, but also facilitate the left and right sides to maximize the killing of the enemy.
In summary, as a part of the ancient city wall structure, the horse face played an important role in protecting the wall, increasing the defensive area, and forming crossfire.