The chief task of this paper is to clarify the cooperative and original character of Yamada’s “ANALYSIS OF JAPANESE CAPITALISM.” This paper confirms the cooperative character of Yamada’s work by analysis of the research process, and demonstrates the original character of his work by analysis of its overall structure. Yamada was forced to resign from his post at Tokyo University due to pressure from the Japanese government. In this process, he changed the aim of his study from the abstract theory of Marx into an analysis of Japanese capitalism. It was in these circumstances that he thus wrote the papers that became the foundation of the “Analysis.” Yamada participated with other researchers in an autonomous research group that engaged in cooperative study of the developmental history of Japanese capitalism. By participating in the group, Yamada obtained important viewpoints for the understanding of Japanese capitalism, and these formed the starting point of his work. Yamada’s work concretized these viewpoints into a structural grasp of the reproduction process of Japanese capitalism. The originality of Yamada’s “Analysis” was that it specified the characteristics of Japanese capitalism as militaristic and semi-feudal.