Zu Chongzhi(429~500), whose courtesy name was Wenyuan, was a famous mathematician¹ and astronomer² living in the Song and Qi of the Southern Dynasty. He was a native of Fanyang (now Laiyuan, Hebei Province).

祖冲之(429 ~500 ) , 字文远，南朝宋齐范阳(今河北涞源)人。

双语阅读之中国历史名人:祖冲之

He did not take for granted the established theories of previous scholars and was skeptical³ to their specious⁴ academic conclusions.

他主张决不“虚推古人”，批判地接受前代的学术遗产，敢于怀疑古人错误陈旧的结论。

Audaciously, he insisted to put forward new theories by precise measurements and prudent⁵ calculations.

亲自进行精密测量和仔细推算，勇于提出自己的新见解。

After careful observations, he identified the mistakes of the calendar used then and compiled an updated one called the "Daming Calendar" (or Calendar of Great Brightness), the best at his time. In the entire history of China, Zu Chongzhi became the first to take into consideration in calendar calculations the differences between the tropical and siderreal years.

经过实际观测，祖冲之指出何承天编制、为当时刘宋王朝奉行的元嘉历有不少错误。于是编制了新历法《大明历》，在中国历法史上第一次考虑了岁差影响，是当时最好的历法。

As a mathematician, Zu Chongzi's most remarkable⁶ achievement was the calculation of pi. The "precise value" he worked out as the ratio of the circumference⁷ of a circle to its diameter is as 355/113, that is, a number between 3.1415926 and 3. 1415927.

祖冲之在数学领域的卓越贡献就是对圆周率的推算，使其精确到小数点后的7位数，介于3.1415926和3.1415927之间。

In the Tang Dynasty, the mathematical work Zhui Shu (or Method of Interpolation) compiled by Zu (now lost) was a required textbook at the Academy of Mathematics, in which students were obliged to read it for four years, the longest time any textbook was required to work on. This book was later circulated to Japan and Korea.

祖冲之的数学专著《缀术》现已失传，在唐代曾作为国子监算学馆的必读书，学习期限4年，是时限最长的一种，后来还流传至日本和朝鲜。

It was said that Zu Chongzhi was also an inventor. He successfully replicated⁸ the legendary⁹ compass wagon¹⁰ and wooden oxen and horses, mechanical vehicles said to have been invented by Zhuge Liang and used to facilitate transportation¹¹.

祖冲之成功地复原过指南车与诸葛亮的木牛流马，他制造的“欹器”用来盛水，“中则正,满则覆”。

He was also the inventor of a "tilted¹² container" used to bail¹³ water and a long-distance boat believed to have the capacity of traveling over 50 kilometers a day.

祖冲之还制造过一种千里船，并在江上试航，日行百余里。