14th February 2020


Needham Research Institute, 8 Sylvester Road, Cambridge CB3 9AF


Lecture seminar at NRI: The (Non-)Transmission of the Jiuzhi li in China


The Jiuzhi li 九執曆, composed in Chinese by Qutan Xida (*Gautamasiddhārtha) 瞿曇悉達 in 718 C.E., is to date the most advanced treatise extant on classical Indian mathematical astronomy. Commissioned by Emperor Xuanzong 玄宗, the text was known to Yixing 一行 and other court astronomers, as well as some Chinese Buddhists during the Tang Period. Despite its advanced mathematical (such as trigonometry) and astronomical content (such as nodal precession), the work was poorly received among the Chinese contemporaries and was eventually lost until it was rediscovered in the Ming Dynasty. The Chinese historian of science Chen Jiujin 陳久金 thus lamented how the Indian work was unfairly treated and its contribution to Chinese astronomy unrecognized, and as a result its non-transmission was a missed opportunity for what could have been a major advance in Chinese science. The annotated translation of Yabuuti Kiyosi is considered to date the most comprehensive study of this text, though many riddles connected to its content remain unsolved. A short passage from the beginning of the Jiuzhi li on Indian calendrical calculation will be read in this session. Philological issues related to the provenance, technical vocabulary, and translation style of the text will also be examined.