This research examines “lesson study” as a traditional model of creating professional knowledge in schools. “Lesson study,” typically defi ned as teachers’ classroom based collaborative research, has a long history in Japan as a shared professional culture with potential for enhancing learning, enriching classroom activities and transforming the school environment. A case study method based on historical data is the primary approach used in this research. Detailed description and analysis of lessons are provided, individual lesson plans are examined and exchanges of views between teachers are discussed. The fi ndings are intended to help clarify the cultural and historical role of lesson based research in Japanese schools, and also the signifi cant infl uence that lesson study has exerted on developing a culture of shared professionalism in Japan
