To UNDERSTAND the roots of both Japanese and what we call Anglo,American corporate decision,making we must examine the basic cultural assumptions and theoretical underpinnings that condition such decision,making. An assumptive value, and especially a cultural assumptive value, is related to the belief or value system that basically is accepted by society at large. Most people simply take for granted that certain beliefs or values are part of their culture, are real and therefore do not question them. This tendency builds over hundreds of years of generational modifications and then becomes the real world based on historical evolution. Therefore, if we look at the differences in assumptive worlds between Japan and Anglo,American countries, representing the English,speaking world, we find that there are a number of basic assumptions that are culturally specific, and if we look at the theoretical framework in which to lodge this explanation we will then uncover the background to the present decision,making processes that are embodied in the large Japanese corporations.