The Japanese approach to problem-based lessons is well known for the selection of interesting, challenging problems, the highly-planned teacher moves, and the facilitation of student attempts toward solving the problem. This talk will revolve around one geometry problem, taken from a Japanese 8th-grade lesson filmed for the TIMSS video study, as a case of how rich problems can be used to teach a multitude of mathematical ideas. I will also describe the learning opportunities this problem offered for teachers in terms of reflecting on their pedagogical considerations when teaching geometry in problem-based lessons.