Lüli yuanyuan 律曆淵源

(Qinding) Lüli yuanyuan (御定)律曆淵源 "(Imperially endorsed) Origins and foundations of musical tuning, calculation, and the calendar" is a collection of three treatises on astronomy, mathematics, and music that assemble Chinese and Western knowledge in these three fields. It was compiled on imperial order during the Kangxi reign-period 康熙 (1662-1722) under the supervision of Prince Yūnlu (Ch. Yunlu 允禄, 1695-1767). The main compilers were He Guozong 何國宗 (d. 1767) and Mei Gucheng 梅谷成.

The emperor aimed to have this book compiled was that he had become aware that the Jesuit missionaries who worked as astronomers at the imperial court brought with them knowledge that covered issued which Chinese scientists had never asked about. The concrete occasion was that the Directorate of Astronomy (qintianjian 欽天監) had made an error in the calculation of the solar term Xiazhi 夏至 (see calendar). The Kangxi Emperor therefore ordered the Director of Astronomy to make use of Western calculation methods that "did not fail in any salient point" (da dun bu wu 大端不誤).

The book was begun in 1713 and finished in 1722, and was printed by the imperial printing shop in 1724. The whole collection has a length fo 100 juan and consists of the parts Lixiang kaocheng 曆象考成 (42 juan), Lülü zhengyi 律呂正義 (5 juan), and Shuli jingyun 數理精蘊 (53 juan).