Life

Wang Fan was from Lujiang Commandery (庐江郡), which is located southwest of present-day Lujiang County, Anhui. He started his career in Wu as a Gentleman of Writing (尚书郎) during the reign of the first Wu emperor Sun Quan or second Wu emperor Sun Liang, but was dismissed from office.

During the reign of the third Wu emperor Sun Xiu, Wang Fan served as a Central Regular Mounted Attendant (散骑中常侍) alongside He Shao, Xue Ying and Yu Si, and was given an additional appointment as a Chief Commandant of Escorting Cavalry (驸马都尉). He received much praise from his contemporaries. When the Wu government sent him as an ambassador to Wu's ally state, Shu, he was also highly regarded by the Shu government. Upon returning to Wu, he served as a military supervisor at the Wu military garrison in Xiakou (夏口).

During the reign of the fourth and last Wu emperor Sun Hao, Wang Fan became a Regular Attendant (常侍) alongside Wan Yu. Although he was initially close to Sun Hao, he gradually became alienated from the emperor as other officials slandered him in front of the emperor and as he became more outspoken against the emperor's outrageous behaviour. In 266, he offended Sun Hao and ended up losing his head. Sun Hao also exiled his family to the remote Guang Province in the south. Lu Kai, the Imperial Chancellor of Wu during Sun Hao's reign, lamented Wang Fan's unfortunate end.

Wang Fan had two brothers, Wang Zhu (王著) and Wang Yan (王延), who were also well-known learned men in Wu. Both of them were killed during a rebellion started by Guo Ma in 279, which was one of the events leading to the fall of Wu in 280.

Contributions to mathematics and astronomy

Wang Fan was proficient in mathematics and astronomy. He calculated the distance from the Sun to the Earth, but his geometric model was not correct. In addition, he gave the numerical value of π as 142 / 45 = 3.155…, which was not as accurate as that given by the mathematician Liu Hui, who lived around the same time as him.

生平

王蕃始为尚书郎，后免官。孙休即位后，王蕃与贺邵、薛莹、虞汜俱为散骑中常侍，皆加驸马都尉。当时人对王蕃的评价甚高。后王蕃作为使者前往蜀汉，蜀汉人对其称道。回到吴国后，王蕃任夏口监军。

孙皓即位后，他重为常侍，和万彧同官。王蕃本和孙皓有旧，但这友情招来万彧妒忌，受其多次与孙皓宠臣中书丞陈声在孙皓面前挑拨离间，加上自身刚正，逐渐和孙皓产生矛盾。

甘露二年（266年），丁忠出使西晋归国后，王蕃受到孙皓邀请赴宴，当时王蕃大醉倒地，受到孙皓怀疑而不高兴，并被抬出外。不久王蕃被召回宴会，还是不清醒，因自身性格威严而举止自若，孙皓气得召其手下将王蕃斩死，虽受到滕牧和留平的求情但不成，王蕃被斩于大殿，享年三十九岁，尸体被抛在野外，家属流放广州。丞相陆凯曾在奏疏中痛惜此事。

家庭

有弟弟王著、王延，也是一时名士，可惜死于郭马之乱。

学术贡献

王蕃通晓天文、数学。撰有《浑天图记》、《浑天象注》，曾根据浑天说和长期的天象观察，精心制作浑天仪，以三分之长为一度，周长一丈零九寸六分，介于古浑仪和张衡制浑仪式之间，在「浑仪」上，周天为三六五又五八九分度之百四十五。「浑仪」可以标明天球与日月星辰的运行，从而说明冬至、夏至、春分、秋分等节气，以及何时昼长夜短，何时昼短夜长，何时昼夜相当，他由此制订了《乾象历》。

王蕃认为：日距离其下临之地为八万里，以此为股，以一万五千里为勾，应用已知的勾股求弦法，测出日距阳城（今河南登封）为八万一千三百九十四里三十步五尺三寸五分，再以阳城为中心，以阳城与日距离为半径，算出周天长度。他采用的圆周率为π=3.155，与刘徽的「徽率」（π=3.1416）、南朝祖冲之的「祖率」（π=3.1415926与3.1415927之间）很相近，为中国天文学的数学作出了可贵的贡献。