Li Si was commissioned to complete the writing reform implemented by the Qin Dynasty. During the Warring States Period, although the basic structure of writing in various countries was the same, there were differences in the traditional and simplified fonts and the positions of radicals. Li Si was ordered to unify the script. Based on the script of Qin and the script of the Six Kingdoms, he formulated Xiaozhuan and wrote it as a model for implementation throughout the country. At that time, there was also a popular calligraphy called official script, which was simpler than Xiaozhuan. The books have the same text, and Xiaozhuan is used as the standard writing; "poems and books are burned" to strengthen ideological control; officials are regarded as teachers, and private study is strictly prohibited.