There are also Lu Ban, Zhang Heng, Cai Lun, Bi Sheng, Li Shizhen ... Shen Kuo, Guo Shoujing, Zu Chongzhi and so on. Let's compare Cai Lun and Zu Chongzhi. By the beginning of the 7th century (Sui and Tang Dynasties), it began to spread eastward to Korea and Japan. In the 8th century, it was introduced to Samarkand from the west, and then to Baghdad ... The invention of papermaking is not only a great change in papermaking materials, but also of epoch-making significance in the history of human civilization. Zu Zu Chongzhi Chongzhi (429 ~ 500), a famous mathematician and scientist in the Southern Dynasties, was born in Laishui, Hebei Province. He has made great achievements in mathematics, astronomy, calendar and mechanical manufacturing. On the basis of predecessors, the calculated value of pi is between 3. 14 15926 and 3. 14 15927. He is the first mathematician in the world to make the value of pi accurate to the seventh decimal place, and put forward the approximate ratio of 22/7 and the secret ratio of 355/ 1 15927. German Otto didn't reach this level until 1573, more than 1000 years earlier than Europe. Therefore, people call the secret rate "ancestral rate". The Da Ming Li compiled by him first considered the calculation of precession, and stipulated that a year was 365+038+0 days. The data of the sun and moon cycles are more accurate than other calendars at that time, and great achievements have been made in mechanical manufacturing. The compilation techniques and annotations of Jiu Zhangyi have been lost, including Yi Lao Zhuang Yi Shi, The Analects of Confucius, Zu Chongzhi Collection (565,438+0) and its book Different Annotations (some people say it's South).