Lesson study: A case of expansive learning

Lesson study is increasingly used throughout the world as a model of collaborative professional learning. In this article we describe the theoretical foundations of an ongoing study which seeks to explore how we might inform collaborative learning with a focus on the development of curriculum coherence. The study involves collaboration between teachers and researchers in both the United Kingdom and Japan. We draw on the theory of expansive learning as a development of Cultural Historical Activity Theory and give insight into the potential this has to inform our work with a range of didactical devices or artefacts that provide connections across topics of conceptual understanding of mathematics and development over time. Expansive learning as a theoretical lens helps us understand our exploratory work in this area and provides insights into how this may be taken forward over the course of the study