MIURA and so on noted that medieval Europe was supported by the knights who were 'armed suzerain' emerging on the frontier by the Great Barbarian Invasion of Germanic peoples, positioned the bushi, who flourished in the frontier society centering on Togoku (the eastern part of Japan, particularly Kanto region) from the middle of Heian period in Japan, as 'armed suzerain' who were the same as the knights, 'discovered' that there also existed medieval times in Japan, which was the only country in Asia, and insisted that Japan could be modernized.
三浦らは、ヨーロッパの中世が、ゲルマン民族の大移動によって辺境で発生した「武装した封建領主」である騎士によって支えられていたことに着目し、日本で平安時代中期から東国を中心とした辺境社会で活躍した武士を騎士と同じ「武装した封建領主」と位置づけ、アジアで唯一日本にも中世が存在したことを「発見」し、日本は近代化できると主張した。