Tsu Chung-Chi is also the name of a small crater on Earth's moon, see also Tsu Chung-Chi (crater)

Zu Chong-Zhi is also the name of asteroid 1964 VO1, see also 1888 Zu Chong-Zhi

Zu Chongzhi (祖冲之, pinyin Zǔ Chōngzhī, Wade-Giles Tsu Ch'ung-chih) (429-500) was a Chinese mathematician and astronomer during the Liu Song and Southern Qi Dynasties (of the Southern Dynasties).

His ancestors hailed from Qiu district, Fanyang Commandery (part of modern Beijing). To flee from the ravages of war, Zu Chongzhi's grandfather Zu Chang moved from Hebei, in north China, to south of the Yangtze River, as part of the massive population movement during the Eastern Jin Dynasty. Zu Chang at one point held the position of "Minister of Great Works" (Dàjiàngqīn) within the Song Dynasty (420-479) and was in charge of government construction projects. Zu Chongzhi's father also served the court and was greatly respected for his erudition.

Zu Chongzhi was born in 429 in Jiankang (today Nanjing). His family had historically been involved in astronomy research, and from childhood Zu Chongzhi was exposed to both astronomy and mathematics. When he was only a youth his talent earned him much repute. When Emperor Xiaowu heard of him, he was sent to an Academy, the "Huálín Xuéshěng", to perform research. In 461 in Nanxu (today Zhenjiang in Jiangsu) he was engaged in work at the office of the local governor.

His achievements included:

• the Daming calendar (大明曆) introduced in 465.
• deriving two approximations of pi, which held as the most accurate approximation for π for over nine hundred years. His best approximation was between 3.1415926 and 3.1415927, with 355/113 (密率, Milü, detailed approximation) and 22/7 (约率, Yuelü, rough approximation) being the other notable approximations.
• finding the volume of a sphere as being 4πr³/3, where r is radius.

Trivia

Asteroid 1888 and crater Tsu Chung-Chi on Moon are both named after him.

429 births | 500 deaths | Chinese astronomers | Chinese mathematicians | 5th century mathematicians

Zu Chongzhi | Zu Chongzhi | 祖沖之 | Ču Čungdži | 祖冲之