This research is based on an approach that looks at cross-cultural research design as a "lens" for a deeper understanding of what goes on in the classroom. The research question is how a cross-cultural study like this one can lead to identifying the cultural script of teaching and help educators reflect on their practice. In this context, Chinese lessons could be described as a case-based study of pedagogical reasoning that drives a shift from focusing on "content" to "competence". This article draws on qualitative data collected by the researchers and a cross-cultural analysis of a science lesson in an elementary school in Beijing, China. Using the Japanese educators' critiques and Chinese reviews, the article determines the cultural script of teaching science (the first research question) and the way Chinese teachers reflect on their practice through the Japanese lens (the second research question). This study exposes the importance of teachers' understanding and reflecting on their practice, "technically," "practically," and "critically." The analysis results show how teachers learn to change their lenses, to reflect on their teaching and reconstruct their understanding about teacher professionalism through at least four basic elements: "didactics," "praxis," "pedagogy," and "theory."