This document describes a study that used a variation of lesson study led by school mentors to contribute to the development of student teachers. The study explored how the student teachers and mentors collaborated to examine pedagogy, and what they learned from the process. Interviews with participants showed that mentors and student teachers believed the lesson study approach was impactful and useful for teacher learning, though there was variability in how lesson study was implemented. Both mentors and student teachers reported learning about student engagement and responses, and growing in their understanding of teaching pedagogy through examining the "pedagogical black box" of the classroom.