Due to the critical study of Kohei Saito on Marx’s notes written after 1868, the image of Marx as ecologist is focused on today. According to Saito, Marx tried to rewrite Capital from the ecological viewpoint. Prior to Saito, however, a heterodox Marxian political economist Yoshiro Tamanoi has referred to the existence of Marx’s notes during 1970s, even when the contents of the notes had not been disclosed. Tamanoi emphasized that Marx had shifted his major interest from the logic of capital to traditional communities which had conducted the material circulation between nature and humans. According to Tamanoi, Marx studied various types of non-western communities, such as Russian Mir, in order to find out the solution to retrieve the material circulation destroyed by the capitalist mode of production. In this paper, the light is shed on the concept of living system, i.e., the concept which, Tamanoi believed, must be placed at the center of the material circulation between nature and humans. Living system is a system which takes in the heat and matter in the state of low entropy and gets rid of those in the state of high entropy in order to sustain life. According to Tamanoi, late Marx’s study on communities could be extended to the search for the socioecological system which keeps its entropy in terms of heat and matter as low as possible in order to sustain the metabolic movement of the system.