Although there have been a lot of researches on it, the concept of the term, "Yongsa[用事]" is still not clearly defined. It is because there have been unsolved problems with regard to the characters of the source of "Yongsa", and the exact meaning of "Sa[事]" and "Yong[用]."
It is common knowledge that the source of "Yongsa" should be in the form of literature but actually the contents transmitted by word of mouth can be included in "Sa." The scope of the source of "Sa" varies depending on the belief and cognitive structure of those who use and accept "Yongsa." Also, the scope of the source varies depending on the character of the text or the circumstances of writing.
What belong to "Sa" are event, knowledge, contention, and the method of formation. Some scholars distinguish it from the "Yongsa" of the 'method of formation' as "Jeomhwa[點化]." In this study, "Jeomhwa" is regarded as being included in "Yongsa", but in order to solve this controversy, separate researches are needed.
With regard to the meaning of "Yong", the terms "Gayong[假用]", "Chayong[借用]", and "Banyong[反用]" become controversial issues. "Gayong" is not useful since it is not the term that denotes the method in which "Yongsa" is formed. "Chayong" should be regarded as a method to use one of new meanings derived from original meaning. With regard to "Banyong", the question of whether "Yeongsa poetry[詠史詩]“ or "Nonsa poetry[論史詩]” can be regarded as cases of "Banyong" arises.
In conclusion, "Yongsa" can be defined as a method of composition that quotes or modifies former text's event, knowledge, assertion, the method of formation, and makes them as part of the text in order to enhance the persuasiveness and appeal of the meaning and sentiments of the message to be conveyed.