In "osmotic learning" a student passively observes and presumably absorbs clinical knowledge. Unfortunately, clinical teaching based on this style tends to result in low student motivation to study, which leads to low faculty motivation to teach. Here we consider how to improve medical education in Japan based on a case study of a Japanese student's (H.I.) participatory experience with the adult learning model in the United States. 1) A Japanese medical student analyzed the weekly evolution of her responsibilities and contributions to patient care during a 1 month clinical rotation at the University of Michigan. 2) She participated through direct contact with 235 patients during the 1 month rotation. Starting with simple contributions to patient care, over time she became an active member of the treatment team. Due to the ever-increasing relationship of trust built during the rotation, the faculty member could give the student tasks requiring more responsibility. This led to a relative reduction in the faculty member's workload and, in turn, increased teaching efficiency.3) From this case study, we conclude that clinical education based on the adult learning model can be applied in Japan, where "osmotic learning" has been prevalent, and that it can increase the motivation of medical students to learn and faculty to teach.