Cefu Yuangui (冊府元龜) extensively quotes texts from the Book of the Later Han (後漢書), containing numerous variant readings. By employing computer technology to digitize various paper versions of Cefu Yuangui and Book of the Later Han, and through programming comparisons supplemented with manual proofreading, a database of variant readings where Cefu Yuangui cites the Book of the Later Han was established. From this database, 75 sets of ancient and modern characters were sorted out. The majority of these cases involve the use of ancient characters in the Book of the Later Han and modern characters in Cefu Yuangui, with a few instances in reverse, but there are also cases where both texts use a mix of ancient and modern characters. This reveals the characteristics of the times of the emergence and use of ancient and modern characters during the Wei, Jin, Northern and Southern Dynasties, as well as the Two Song Dynasties. Some conclusions drawn from this study can provide references and insights for further improvements of the revised version of Cefu Yuangui.

Qianjin Yaofang by Sun Simiao of the Tang Dynasty is a comprehensive collection of medical classics. The original version has been lost. Zhenben Qianjinfang, as the earliest extant version, contains a large number of common characters and has a very high reference value. This article takes the common characters in Zhenben Qianjinfang as the object of investigation, and uses research methods such as document collation, Chinese character studies, and exegesis to comprehensively sort out and systematically describe the common characters in the book, in order to provide reference for the study of ancient medical books. Based on preliminary statistics, there are a total of 661 pairs of characters that have a relationship between orthodox and secular in Zhenben Qianjinfang. Referring to Mr. Zhang Yongquan’s classification method of vulgar characters, these vulgar characters can be divided into nine categories, including changing meanings, changing sound symbols, simplification of glyphs, multiplication of glyphs, writing variation, splitting or merging of components, displacement of components, newly created vulgar characters, and borrowing pronunciation and common words, etc. For each type of common characters, typical examples are cited for critical analysis to explain the formation mechanism and rationale behind the glyphs of the common characters. To sum up, the formation of the common characters in Zhenben Qianjinfang is mainly the result of the combined effects of two internal and external factors. The evolution of glyphs, the need for semantic expression, and the phonetic characteristics of Chinese characters have contributed to the emergence of vulgar characters within the language system, while external factors such as politics, technology, and culture have also had a certain impact on the formation of common characters.