Zu Chongzhi’s Birthday doodle appeared on Google homepage on 20^{th} April of 2009. Zu Chongzhi was a Chinese astronomer. More than astronomical observation , it’s his mathematical skills make him renowned all over the world.

Google’s Zu Chongzhi’s Birthday Doodle ,we can see the replacement of alphabet ‘o’ with the circle which points to his famous interpretation for the value of Pi. For about 900 years Zu’s approximation for value of Pi was taken valid in mathematics. 355/113 approximation of Pi is also included in the Zu doodle.

Zhui Shu is Zu Chongzhi’s text book which includes all details of his findings, Unfortunately that book was lost during the period of Song Dynasty. Apart from finding the approximate value for Pi, there are many other contributions in the field of mathematics and astronomy in his name.

It’s is believed that Daming calendar is introduced by Zu Chongzhi in AD 465. Calculation of Jupiter Year, number of sun and moon overlap etc are the some other inventions done by him during that period when there were no sophisticated tools and techniques for doing researches and experiments. Zu’s other mathematical contributions includes the equation for finding the value of sphere.Though Zu Chongzhi found the Daming Calendar during AD 465, it was not accepted by the Emperor over that time due to certain oppositions from the astronomers lived during that time.

Many debates and oppositions took place during the time to take Daming Calendar as a valid calendar to follow. It was only after his death with his son’s initiation the calendar was published officially as the valid one.

Google by publishing this birthday special Google doodle dedicated to mathematician honored Zu Chongzhi and made world recognize him and his inventions which became very useful for mankind in many areas. The way in which the designer included the doodle was very relevant for the message of the day.