Yao Jiheng 姚際恒 (1647-1715), courtesy name Lifang 立方 or Shouyuan 首源, style Shanfu 善夫, was an early Qing period 清 (1644-1911) philosopher. He hailed from Tongcheng 桐城, Anhui, but later moved to Renhe 仁和 near Hangzhou 杭州, Zhejiang. Yao was famous for his wide expertise in all different types of writings, but specialized on the Confucian Classics in their original shape from the Han period 漢 (206 BCE-220 CE).
Yao belonged to the text-critical school (Hanxue 漢學) that analysed these texts with the help of critical methods. He became so acknowledged with this method that he became a master in differing authentical texts from forgeries or texts that were wrongly attributed to a certain person or to a wrong age. According to his findings, there were lots of falsified scriptures, many of which had even attained a high scholarly status. Yao therefore decided to publish his findings, first his analysis on the Shangshu 尚書 "Book of Documents", in which he explained that the old-text (see new-text and old-text debate) Guwen Shangshu 古文尚書 was without doubt a forgery.
His large book on forged scriptures, Gujin weishu kao 古今偽書考, is divided into several parts, the first analysing text that were forgeries in total, the second writings that were partially fake, the third part books that were authentic, but whose publishers used a false name of author, the fourth books whose title was fabricated, and finally books whose author is unknown. Yao Jiheng also wrote the books Yongyanlu 庸言錄 and Shijing tonglun 詩經通論.