This paper compares the P\'ansori of Korea and the Yimakan of the Hezhen people and develops a general theory concerning the process of change in oral epics based on this comparison. P\'ansori and Yimakan have similarities such as a composite narrative method of spoken words and song (ch\'ang), the process of the removal of shamanic elements, a change in the character of the performing class, and possession of a rhythm. They also have differences in whether or not there is an accompanist, whether or not the lineage is clear, whether or not the narrative structure is open, and whether or not the form is song-oriented. Based on this, the results of an examination of the process of change in oral epics may be shown briefly by the following diagram: Conclusion based on similarities: Festival epic ----------------> Recreational epic ↓ Case in which only the performing class is related to festivals: P\'ansori Case in which both genre and performing class are related to festivals: Yimakan Epic which is both recreational and contains festival-related elements (or shamanic elements) --------> Recreational epic If Yimakan originated from a festival epic or something like it, then P\'ansori can be seen as an interim form of this as it progressed toward becoming a recreational epic. However, there is a difference in whether both the genre and performing class are related--like the Yimakan--or whether only the performing class is related--like the Pansori. Thus the fact that shamanic elements are more concentrated in Yimakan works than in P\'ansori is something which cannot be avoided. Conclusion based on differences: Recreational epic centered on conveying a story: Yimakan ---> recreational epic centered on conveying song: P\'ansori Narrative structure in which song is subordinate to the spoken word: closed Narrative structure in which the spoken word is subordinate to song: open It may be discovered that, compared to Yimakan, P\'ansori is a very refined and specialized oral epic. From the very beginning, P\'ansori relied on the free and unrestricted singing ability of the individual performer (Kwangdae) and developed into an oral epic centered on conveying song. On the other hand, Yimakan relied on the clear voice of the performer (Yimakannawi) and focused on how to effectively convey the narrative content, that is, it developed as an oral epic centered on conveying the story. Therefore the P\'ansori performer could develop the P\'ansori as his or her own special performance or production. The oral epic is ultimately a genre which is challenged, not with the problem of how to express the narrative content, that is, the story, but with the problem of how to convey that story. Thus the problem arises of whether to adopt the compound narrative method of both song and spoken word, or to adopt a narrative method which emphasizes one of the two, but that which utilizes that compound narrative method of song and spoken word rather one that excessively emphasizes one aspect can be said to be an oral epic possessing the highest degree of workmanship. This is because the rhythm can be nothing but monotonous if the narrative method is comprised only of song or only of spoken word, and the performing class has that much less room to display their personal skills. On this point it may be said that both P\'ansori and Yimakan have succeeded, but the P\'ansori has much more effectively developed in terms of how to convey the story lyrically than has the Yimakan. There is a need to consider this point when setting forth a general theory of the process of change in oral epics.