Horserider Theory

The “Horserider Theory” formed by Egami Namio in 1949 has caused much controversy amongst a majority of Japanese academics. This is so because it suggests Japanese racial impurity and that early Japanese society was heavily influenced by Korean outsiders who conquered and invaded Japan during the late fourth century to the early fifth century. Opposition to the “Horserider Theory” cites the lack of archaeological evidence and the misinterpretation by Egami of historical literary records in order to refute the theory. However, Western scholars of premodern Japanese history, as well as more liberal ethnic Japanese historians, support the theory (Edwards 265-266). The “Horserider Theory” is accurate because of corresponding archeological and literary

Such factors include strikingly similar key-shaped hole tombs containing like strains of jade found in modern Busan, South Korea and in Kyushu, Japan (Lee 7). However, the leading premise used in Egami’s theory is the radical and abrupt change that occurred in Japan during the late Kofun period (Kirkland 110). Egami states that:
“During the Late [Kofun] era the peaceful, agricultural, magico-ritualistic, Southeast Asian qualities of the culture of the Yayoi period and the early [Kofun] era were replaced to a large extent by the very practical, warlike, king-and-noble-dominated, North Asian qualities of the equestrian people” (Kirkland 110 and Egami et. al).
Egami goes on to explain that this change was too abrupt to have occurred naturally by the indigenous peoples of Japan because the peaceful and mainly agricultural society of Japan at the time would have no reason to willingly adopt such a grotesque, violent alien culture (Kirkland 110). Thus, Egami concludes that these recent cultural shifts “‘correspond in all respects’ to cultures of conquering continental peoples [... and] the transformation must reflect ‘the subjugation and control of Japan by military force’” (Kirkland

Criticism also stems from the lack of archaeological evidence regarding any type of battle that may have ensued upon this conquest. Despite this lack of battlefield debris, Egami cites historical literary records of both Korea and Japan to support his claim that continental Koreans overran Japan. As told by Japanese records, Jimmu, the founding emperor, crossed the Inland Sea from Kyushu into Kansai, and during his voyage, he met a deity riding on a turtle. In parallel, the Korean myth of Puyo’s founder, Chumong, states that Chumong fled the ruling of an evil king by crossing waters on a turtle, and across these waters he found a new state (Kirkland