It is said that the writing brush was invented by Meng Tian. Meng Tian was a general under Qin Shihuang. After Qin unified the six countries, Meng Tian led the army to defeat the Xiongnu and recovered a large area of land. At that time, Qin Shihuang's military discipline was very strict, and major military situations had to be reported within a limited time, and those who delayed were sentenced to death. There was no paper and pen at that time. Meng Tian was very nervous about covering the war. Because the memorial hall at that time was carved with a knife, which was very time-consuming. Once, during the war, he went out hunting. There are many prey such as wolves and rabbits, so he tied these prey behind the horse and dragged them back to the station. On the way, he found another blood spot on his way. His heart beat. When he came back, he cut off the tails of wolves and rabbits, tied them with wooden sticks and wrote them on bamboo slips. The effect was not good. He accidentally dropped his robe, and the words on the bamboo slips disappeared at once. When his men tried to change his clothes, he stopped him and ordered his men to take out a piece of silk and write it with animal blood. Later, Meng Tian was ordered to build the Great Wall in the north. Because many dissenters are eager to nip in the bud and keep asking about the progress of the project, Meng Tian's secretary stays up almost every day to catch bamboo tubes and play with intimate feelings. On the day of completion, Meng Tian was eager to report his achievements and decided to write the paper by himself, but the bamboo tube carving was too slow. He remembered what he had thrown into the lime pit last time, so he fished it out and tried it with cinnabar. It turned out to be much better than last time. After selection, he felt that the wolf's tail was better and the paper written on white silk was smoother. Later, Meng Tian often wrote the memorial with this pen, and this pen must be made of wolf hair, so Meng Tian named it "pen", which means it is made of wool and bamboo. We still call the writing brush Meng Tian pen. Only later generations gradually found cheaper ink to replace cinnabar because it was too expensive.