IMPULS (International Math-teacher Professionalization Using Lesson Study) has offered a mathematics lesson study immersion program in Japan for a decade, and recently began offering an online course.  Taught by Akihiko Takahashi and Tad Watanabe, the course is designed for local teams of up to 10 educators, including two representatives from each team who participate in the 6-8 hour synchronous course. The course immerses participants in a full lesson study cycle, focused on a “Teaching Through Problem-solving” style lesson. The two representatives in the synchronous elements work directly with the instructors and 30 synchronous course participants.