Zu Chongzhi (429-500), whose courtesy name was Wenyuan, was a famous mathematician and astronomer in the Song and Qi of the Sounthern Dynasty. He didn’t take for granted the established theories of previous scholars and was skeptical to their specious academic conclusions. He insisted to put forward new theories by precise measurements and prudent calculations. He identified the mistakes of the calendar used then and complied an updated one called the “Calendar of Great Brightness”, the best at his time. In the entire history of China, he became the first to take into consideration in calendar calculations the differences between the tropical and sidereal years.

As a mathematician, his most remarkable achievement was the calculation of pi. The “precise value” he worked out as the ration of the circumference of a circle to its diameter is between 3.1415926-3.1415927. In the Tang Dynasty, his mathematic book “Method of Interpolation” was a required textbook at the Academy of Mathematics. It was said that he was also an inventor. He successfully reduplicated the legendary compass wagon and wooden oxen and horses, mechanical vehicles said to have been invented by Zhuge Liang and used to facilitate transportation. He was also the inventor of a “titled container” used to bail water and a long-distance boat believed to have the capacity of traveling over 50 kilometers a day.