Purpose: The paper describes two reflective instruments: a reflective diary (RD) and a joint learning protocol (JLP) for teachers' knowledge creation in lesson study (LS), reflects on teachers' reactions and encountered challenges and draws inferences on how teachers' learning and knowledge creation could be facilitated more effectively in LS through "learning keeping." Design/methodology/approach: This qualitative case study of an action research project utilizes the data collected through the narrative inquiry within an LS initiative with four English as a foreign language (EFL) teachers in a school in Spain. Findings: The study suggests that the incorporation of reflective writing in LS as a method of keeping records of teachers' individual and collective reflections should be considered "a good practice" and yet another important mechanism facilitating teachers' learning in LS. Research limitations/implications: The study is limited by its scope since the applied LS model suggests carrying out three consecutive cycles rather than two. Originality/value: Firstly, the two proposed instruments could be of practical value to educators and facilitators employing LS as an approach to teachers' professional learning. Secondly, the study adds to the discussion on the mechanisms fostering teachers' learning in LS by emphasizing "learning keeping" as a form of record-keeping through reflective writing. Thirdly, the study is set in the new for the LS community context, in the autonomous community of the Basque Country, Spain.