Postgraduate clinical training for physicians in Japan has been mandatory since 2004, with the provision that the system itself is to be revised every 5 years if necessary. Major revisions were implemented in 2020, involving the objectives, strategies, and evaluations of the clinical training program. Among the revisions was a section on professionalism in the first part of objectives. As one of the committee members involved in the process of this revision, I provide an explanation of the historical background, learning strategies, and assessment of professionalism in physician training.