2. After Qin Shihuang unified China (22 1 year ago), Xiao Zhuan implemented the policy of "the words are the same, the cars are on the same track", and unified measurement is responsible. On the basis of the original seal script used by Qin, Xiao Zhuan simplified and cancelled the variant characters of other six countries, creating a unified writing form of Chinese characters. It was popular in China until the end of the Western Han Dynasty (about 8 AD) and was gradually replaced by official script. But because of its beautiful font, it has always been favored by calligraphers. Because of its complex strokes and simple form, it is possible to add twists and turns and seal cutting at will, especially the official seal that needs anti-counterfeiting. Seal script was always used until the collapse of feudal dynasty and the emergence of modern new anti-counterfeiting technology.