great Chinese scholar from the early period of the Qing dynasty (1644–1911/12) who proved that 25 chapters of the Shujing, or Shangshu, one of the Five Classics of Confucianism, upon which the government modeled itself for more than a thousand years, were forged.

Yan early became interested in determining the authenticity of the Shujing. The work dated from the early Zhou period (1122–771 BC), but after the years of turmoil following the end of the Han dynasty (206 BC–AD 220), only 29 chapters of it remained extant. Then, in the 4th century AD, an alleged copy of the 16 chapters of the “ancient script” text appeared, with 9 additional chapters. These were accepted as authentic. The 54 chapters (later some chapters were divided to make a total of 58) were made one of the bases of the Chinese civil service examination.

Yan spent 30 years making an intensive textual analysis of the work and then published his Shangshu guwen shuzheng (“Inquiry into the Authenticity of the Ancient Text of the Shangshu”), which used historical and philological reasoning to prove that the so-called “ancient script” chapters of the Shujing had been forged. Yan's book helped bring about a new critical reexamination of the Classics.