Purpose: The aim of this paper is to explore the rationale and findings of the implementation of a Chinese lesson study (CLS)-informed model of mathematics teacher education in Italian schools. The study focuses on the modifications and invariance when introducing CLS in a different culture. Design/methodology/approach: In a previous work (Bartolini Bussi "et al.," 2017), the authors focused on a single case of activity inspired by the CLS in Italy, and identified some conflicts emerging between the cultures of teaching in China and Italy and explored the way to overcome the conflicts. In the following years, the authors implemented lesson study (LS) experimentations with dozens of in-service primary school teachers and pre-service teachers who were gradually introduced to the model of CLS. The tensions/constraints occurred prominently when extending the experiments with many dozens of other in-service teachers and pre-service teachers. Findings: The authors highlighted how the process of deconstruction allowed the participants in the study to either appropriate or reject some features of the CLS, linking this process to the cultural differences. Practical implications: The authors believe and argue that LS, and CLS in particular, must be modified in the transfer from one culture to another, considering the cultural beliefs of the involved teachers. Originality/value: The authors claim that the features of CLS compels the Western researchers to adopt local and culturally determined choices and to be aware of the rationale of these choices.