Shijing kaoyi 石經考異 "Research on differences in the Stone Classics" is a book on the Stone Classics compiled during the early Qing period 清 (1644-1911) by Hang Shijun 杭世駿 (1698-1773), courtesy name Dazong 大宗, style Jinfu 堇甫.
Hang hailed from Renhe 仁和 near Hangzhou 杭州, Zhejiang, obtained his junshi degree in 1724 and was made an erudite in 1736, then junior compiler (bianxiu 編修), and finally Censor (yushi 御史) during the Qianlong reign-period 乾隆 (1736-1796).
The 2-juan (in the Hangshi qizhong 杭氏七種 edition) long book was written as a supplement to Gu Yanwu's 顧炎武 (1613-1682) study Shijing kao 石經考. Gu Yanwu had been very interested in the question whether the Stone Classics incised into stone slabs during the Zhengshi reign-period 正始 (240-248) of the Wei period 曹魏 (220-265) were only written in one writing style, or in three typefaces. According to the imperial bibliography Jingji zhi 經籍志 in the official dynastic history Suishu 隋書, there were only two Classics texts written in three different typefaces, namely the Shangshu 尚書 and Chunqiu 春秋, but another passage in the same chapter explains that all of the incised texts were written just in one typeface.
Hang Shijun came to the conclusion that there is no clear written proof that the Wei Stone Classics were written in three typefaces, but it was only a general assumption that the Han-period 漢 (206 BCE-220 CE) Stone Classics had been written in one, and the Wei Classics in three writings styles, and this statement was spread by scholars like Li E 厲鶚 (1692-1752) or Quan Zuwang 全祖望 (1705-1755). The latter even brings forward the argument that the Jingji zhi had wrongly written "one" instead of "three". Zhai Zhongrong 瞿中溶 (1769-1842), author of Han shijing kaoyi buzheng 漢石經考異補正 and Feng Dengfu 馮登府 (1783-1841), author of a revised version also called Shijing kaoyi 石經考異, continued to assume the fact of the multiple writing styles.
Hang Shijun also demonstrated that it was not seven Classics whose text was incised into stone slabs during the Han period, but only five, as can be seen in many contemporary sources. Yet if one takes the Classics Yili 儀禮 and Liji 禮記 as one text ("ritual texts") and the Chunqiu and its commentary Gongyangzhuan 公羊傳 also as one unit, the numbers five and seven are both reasonable. Yet in the biographies of Cai Yong 蔡邕 (132-192), the calligrapher of the Han Classics, and Zhang Xun 張馴 (fl. 175-184), there is talk of six incised texts, which might include the "Confucian Analects" Lunyu 論語. The arguments of Hang Shijun can therefore be countered.
The most problematic point in his book is that he used contradicting sources to prove that Handan Chun 邯鄲淳 (c.132-221) cannot have written the calligraphy for the Zhengshi Classics because he must have been incredibly old at that time, if he had not written the calligraphy much earlier than the actual reproduction of the text in stone.
The Shijing kaoyi (Feng Dengfu's version) is to be found in the series Huang-Qing jingjie 皇清經解, but split up in six texts, each treating the stone inscriptions of one historical period: Han shijing kaoyi 漢石經考異, Wei shijing kaoyi 魏石經考異, etc.