Zu Chongzhi (425-500), born in Fanyang (now
Laiyuan County in Hebei Province), was a great mathematician and astronomer
during the Northern and Southern Dynasty (220-581). His main contribution to the
development of science and technology includes the computation of pi, the
calculation of the volume of sphere, the compilation of the Daming Calendar
(462), and the invention of the south-pointing carriage.

Zu Chongzhi's main contribution to
math is the computation of pi. Records show that Zu worked out the numerical
value of pi -- between 3.1415926 and 3.1415927. It was the most advanced
achievement worldwide at that time. Such precision was not surpassed until the
15th century when Al'Kashi, a native of Samarkand (now Uzbekistan), calculated
pi using a similar method. To honor Zu's great contribution to math, some
foreign math historian suggested calling pi "Zu Lv (the rate of Zu)". It is
astonishing that Zu made the calculation even before the invention of the
abacus, so he did all the work using nothing more than wooden counting
sticks.

Zu Chongzhi and his son, Zu Geng, also
managed to put forward the formula for computation of the volume of a sphere.
*Zhui Shu *by Zu Chongzhi, one of the ten books on *Suan Jing*, was
adopted as the textbook for mathematics in the Tang Dynasty
(618-907).

In astronomy, Zu Chongzi created the Daming
Calendar, taking into consideration the precession of the equinoxes for the
first time in China. This was a major breakthrough in the history of Chinese
calendar.

Zu was successful in producing a new system,
but the new idea got tangled up in red tape. Ministers of the imperial court
spent two years arguing about whether they should use the new Daming Calendar
and might have gone on even longer if the emperor of the time hadn't passed
away. Zu never saw his Daming Calendar put to use. A decade after Zu's death,
the Calendar was at last recognized with years' of efforts by Zu's
son.

Zu was also good at machine making. He
invented the south-pointing bronze carriage and 1000-li Boat which could travel
100 li (1 li = 1/2 kilometers) in a day.

Zu was one of the few Chinese mathematicians
to have a lunar feature named after him. People named a lunar crater at the back
of the moon Zu Chongzhi in commemoration of him. Crater Zu Chongzhi (listed in
the International Astronomical Union's handbook as Crater Tsu Chung Chi) is 28
km wide and located about 20 degrees north of the moon's equator. And the planet
1888 was named "Planet Zu Chongzhi".