Crossbow is a weapon in ancient China, which has become the most advanced weapon in the cold weapon era because of its long range, high hit rate and strong lethality. It consists of crossbow arm, crossbow, bowstring, crossbow neck and crossbow machine. Among them, crossbow machines are mostly cast in bronze and placed at the end of wooden crossbows. Its function is to stretch the machine in advance and fill it for the enemy.

The crossbow machine consists of machine body, hook teeth, observation mountain, hanging knife and pivot (embolism). Cangzhou area has been a traffic fortress and strategic place since ancient times, so some crossbow machines have been unearthed one after another. Cangzhou Museum has a crossbow machine of Han Dynasty, which is narrow at the front and wide at the back, with a small slot on each side of the arrow slot.

The front and rear nails are fixed, and the two nail caps are hexagonal, narrow at the top and wide at the bottom, and the hook teeth of the hanging knife are more flexible. Although its structure is simple, its design is very exquisite, which requires very high requirements on mechanism design, modeling of connecting parts between parts, machining accuracy and surface smoothness, and it is time-consuming and laborious to make.

The crossbow was invented by Chu people in the Spring and Autumn Period, and its structure and manufacture gradually matured in the late Warring States period. After Qin unified the seven countries, the crossbow was made more completely and beautifully, and it was further improved by the development of Han and Three Kingdoms. It is a necessary weapon for ancient military operations and one of the most advanced military weapons in ancient China. "Wu Beizhi Military Capitals" said: "China's sharp weapon is bow and crossbow, but the crossbow is the most useful."

In the history of China, there are many famous battles in which crossbows were used to win, such as the "Battle of Maling" in the Warring States Period, when Pang Juan was sent to unite with Zhao to lead the army against the enemy and ask Qi for help. With Tian Ji as the general and Sun Bin as the strategist, the State of Qi used the terrain to ambush 10,000 archers in Maling. With the surprise attack of "crossbows and crossbows", Wei Jun was defeated, but Wang Wei was captured alive, and Pang Juan committed suicide.

Wei never recovered. There were many generals who were good at crossbow shooting in ancient times. According to Hanshu, the imperial court used the word "crossbow" to describe the bravery of generals, and awarded honorary titles such as "General with strong crossbow" and "General with accumulated crossbow". Besides fighting, crossbows are also used to guard against theft in tombs. In the era of heavy burial, there were many funerary objects in the tomb, and grave robbers entered the tomb to steal property.

So put the crossbow in the tomb, hang the knife with a rope, and the rope passes through the tomb. When entering the tomb, the rope touches the rope, which pulls the hanging knife, the hook tooth sinks into the arm groove, the string slips off the hook tooth and the arrow is shot out. Grave robbers are either dead or injured, which plays a role in protecting graves.