Taejo Wang Geon of Goryeo conquered Naju in 903, before his accession to the throne, and used it as one of his main bases to achieve unification after his accession to the throne. We looked at how Wang Geon fought a total of five battles with Later Baekje related to Naju Chiso while conquering the southwestern sea of Naju. First Battle in 903(victory at Taebong), Second Battle in 910(victory in defense of Taebong), Third Battle in 912(victory at Taebong), Fourth Battle in 930(victory at Later Baekje), Fifth Battle in 935(Goryeo victory). The final winner was Wang Geon’s Goryeo army. Meanwhile, in the process of examining this, it was discovered that there was a movement for the restoration of Later Baekje or a resistance force after the end of the Unification War. This fact was one of the meaningful achievements of this article.