Substitution, one of the six categories of Chinese characters, remained a much disputable issue in the longterm study categories of Chinese characters. The scholars in the Qing Dynasty carried on and developed the theory of substitution of four styles and two functions advocated by scholars in the Song, the Yuan and the Ming Dynasty, concluding the three functions of substitution: word use, word making and concurrent use. Those scholars who specialized in the concurrent function of substitution fell into two groups: one groups took the existence of the words for the standard to distinguish worduse substitution from wordmaking substitution whereas the other just sought the basis of wordmaking substitution with reference to formal structure of the word. Moreover, scholars in the Qing Dynasty took three leading views with regard to the relationship between substitution and extension, especially Duan Yucai, who introduced the theory of “true and false substitution”, and Zhu Junsheng, who redefined the concept of substitution. In Practice, the scholars exposed some problems in their studies of substitution, for example, their confusion over the relationship between extension and substitution.

philology in the Qing Dynasty; studies of the six categories of Chinese characters; substitution; interchangeability; extension