Reassessing the the Mimana Nihon-fu Theory: Evolution of a Contested Historical Narrative

Abstract

This article examines the controversy surrounding the Mimana Nihon-fu (Imna Ilbonbu) theory, which claims that the Yamato court established a colonial outpost on the Korean Peninsula to rule three southern states (Baekje, Silla, and Gaya) from the 3rd to 6th century. The Mimana Nihon Fu theory traces its origins in the Nihon Shoki, often associated with the legend of Empress Jingū’s conquest of the Korean peninsula. The theory gained prominence during the early 20th century, where it served as justification for Japan’s colonization of Korea. Later, the theory was formalized with Suematsu Yasukazu’s The Rise and Fall of Mimana (published in 1949), which presented the Yamato rule of Gaya as a historical fact. In recent decades, however, an increasing number of Korean and Japanese scholars have challenged the validity of the theory. This article analyzes secondary sources to examine how interpretations of the Mimana Nihon-fu theory evolved, revealing how political ideologies have shaped, and often distorted, the understanding of early Korea-Japan relations. It reviews the major evidence cited in support of the theory, such as the contested readings of the Gwanggaeto Stele, the Seven-branched Sword, and archaeological comparisons between Gaya and Yamato tombs. Archeological evidence, including ironworking and pottery, from Gaya, Baekje, and the Japanese archipelago suggest technological and cultural transmission from the Korean peninsula to Japan, meaning that there was a mutual exchange between the two regions rather than conquest. Thus, this article concludes that the Mimana Nihon-fu theory lacks credible historical and archaeological evidence and that the early development of states in Korea and Japan was interconnected rather than hierarchical.