日本東洋史是明治維新以來發展的新學科，發展之初的核心是中國 史，隨著白鳥庫吉對朝鮮、滿洲、蒙古的深入研究，提出東洋史是在 農耕民與遊牧民的南北對抗中發展。江上波夫是北亞遊牧民史第三世 代的研究者，專長是東洋考古學，由 1931-1945 間的滿蒙考古調查的 累積，在戰後 1948 年 5 月出版《アジア‧民族と文化の形成》，提出 「騎馬遊牧民族」概念，延伸白鳥庫吉的南北對抗論，在東亞史視角 下考察日本民族與國家的形成。同年 8 月他在「日本民族文化源流與 日本國家形成」座談會提出大和王朝的統治者是來自東北亞的騎馬遊 牧民，被稱為「騎馬民族征服日本說」，引起討論熱潮。1951-1967 年 間，他從近東考古調查中深化「騎馬遊牧民族」概念，同年 11 月出版 《騎馬民族国家》，完善自身學說的同時，認為「騎馬遊牧民族」與 「定居農耕民族」概念能用於考察世界史。由此可看出，日本歷史學 界在戰後除了以馬克思唯物史觀重新建構歷史外，江上波夫從「騎馬 遊牧民族」建構對東亞史、日本史、世界史的理解。

The study of Tōyōshi, or Oriental History, emerged as a new field of scholarship during the Meiji Restoration. While the roots of Tōyōshi can be found in Japanese studies of Chinese history, it was the scholar Shiratori Kurakichi who expanded the scope of this discipline to include North Asia, focusing on the Korean Peninsula, Manchuria, and Mongolia. He proposed the theory that Oriental History was characterized by a conflict between agrarian populations in the south and nomadic population in the north, a theory that was labelled "North-South Dualism." This article focuses on the work of Egami Namio, a third-generation Tōyōshi researcher who specialized in archaeology. His archaeological discoveries between 1931 and 1945 led him to publish his 1948 book, Asia: The Formation of Nations and Cultures. In it, he expanded the theory of North-South Dualism with the category of "horse-riding nomads." Investigating the formation of the Japanese people and nation, Egami Namio proposed that the rulers of the Yamato Dynasty originated from horse-riding nomads in Northeast Asia. This idea, known as the "Theory of Horse-Riding Nomads Who Conquered Japan," sparked heated debates on the origins of Japanese culture and people. Egami Namio continued to refine his theory, conducting archaeological research in Near Asia between 1951 and 1967, which deepened his understanding of the relationship between horse-riding nomads and agrarian people. His research contributed to the reconstruction of history through the lens of historical materialism. He also offered unique insights into East Asian history, Japanese history, and world history.