Purpose The purpose of this study is to systematically review empirical research on teachers' learning processes in lesson study and learning study in Asian contexts, with particular attention to the mediating role of artifacts in learning. Design/methodology/approach Following Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, a systematic literature search was conducted across major academic databases, resulting in 36 studies. The analysis employed an analytical framework focusing on contextual attributes, theoretical lenses and artifacts mediating teachers' learning, drawing on Stahl's theory of collaborative knowing and artifact-mediated cognition to examine how learning is shaped through collective activity and individual appropriation. Findings The review shows that teachers' learning in Asian lesson study is predominantly conceptualized as a socially situated process mediated by artifacts such as classroom videos, student work, shared lesson plans and theoretical frameworks. These artifacts support collective meaning-making by transforming classroom experiences into shared objects of inquiry, while individual learning emerges through teachers' interpretation and appropriation of group-level meanings. At the same time, the findings indicate that strong consensus-oriented practices can both facilitate focused collaborative inquiry and constrain opportunities for divergent interpretation. Originality/value This review contributes to literature by theorizing teachers' learning in lesson study as an iterative, artifact-mediated cycle of collective meaning-making, individual appropriation and re-externalization. By highlighting how embedded consensus-building practices shape appropriation in Asian contexts, the study offers a nuanced account of the affordances and limitations of lesson planning. The findings provide a conceptual foundation for designing lesson study practices that balance shared focus with conditions supporting individual interpretation and sustained professional learning.
Yoko Takimoto (2026) studied this question.