This extensive research process is termed kyozaikenkyu. It involves the
investigation of a large range of instructional materials, including textbooks,
curriculum materials, lesson plans and reports from other lesson studies, as well
as a study of students’ prior understandings, which makes it possible for
teachers to anticipate students' reactions and solutions to the problems during
the lessons. While the literal meaning of kyozaikenkyu is the study or investigation
(kenkyu) of instructional materials (kyozai), the word kyozai means much more
than textbooks or curriculum materials and needs to involve learning goals.
Thus, according to Watanabe, Takahashi and Yoshida (2008), “kyozaikenkyu, is the
process to help teachers gain a deeper understanding of kyozai” (p. 135).
Moreover, it is important to distinguish between the content to be learned in a
lesson and the tasks, as it is possible to explore the same subject matter with
different kyozai, or investigate different subject matter with the same kyozai (p.