In this paper, "Teaching Expertise in Three Countries" project is used as an example to show the significance and contribution of international comparative research and to think about the possible implications for policy in early childhood education. The project studied the development of expertise in preschool teaching in Japan, China, and the United States by employing 'video-cued multivocal ethnography' to explore how teaching expertise is defined in each of these countries and what processes help teachers acquire advanced teaching skills. This project has shown similarities and culturally specific notions, in what the participants have to say about characteristics of less and more experienced teachers. These research findings raise issues and challenges in early childhood education that resonate with the situation not only in the three countries but also possibly in other countries, such as problematizing the role of remembering and reflection in professional practice and the value of experience.