12: Kyozaikenkyu: A Critical Step for Conducting Effective Lesson Study and Beyond

Since its introduction in the United States in the 1990s (Lewis & Tsuchida, 1998; Stigler & Hiebert, 1999; Yoshida, 1999), lesson study has attracted much attention among U.S. mathematics educators. Many mathematics teacher educators facilitate lesson study. However, as more U.S. teachers engage in lesson study, it is important that lesson study practitioners shift their focus from simply practicing lesson study to practicing lesson study effectively and meaningfully (Fernandez, 2002; Yoshida, Takahashi, & Watanabe, 2003). As Lewis’ quote suggests, lesson study is about the improvement of mathematics instruction, not just the improvement of a single lesson. By planning, teaching, and discussing a publicly taught lesson, lesson study practitioners may learn many things. But for ongoing improvement of instruction, this learning must be purposeful and intentional; it must be about mathematics, mathematics learning, and mathematics teaching. In our experiences with teachers engaged in lesson study, we have found that they often do not attend well to an important step in the process called kyozaikenkyu. In this chapter, we describe this critical step of lesson study and argue for its importance. We also discuss some implications for mathematics teacher educators in their work with both preservice and inservice teachers.