Since the proposal of Best Evidence Medical Education (BEME) by Harden in 1999, there has been an increase in the trend of discussing problems related to medical education using the results of medical education research primarily conducted in English-speaking countries as scientific evidence. However, if medical education, including professionalism and other issues, is discussed without taking into consideration cultures and systems, its essence may be overlooked. The present paper introduces a theory of professionalism regarding Japanese physicians using bushido (samurai spirit) as its model. I hope that the present paper will serve as a foundation for discussions concerning education on professionalism for physicians in Japan.