Before we discuss the "where," let’s discuss the "why." Western textbooks often follow a "spiral" approach (touching on a topic, leaving it, and returning later). Japanese textbooks follow a "mastery" approach.
Japanese high school math books are famously thin but dense. The philosophy is Shōshi (少士)—less content, mastered deeply. Instead of 800-page doorstops, a typical Japanese math text is around 250-300 pages. This doesn't mean less learning; it means less fluff. Japanese High School Math Textbook Pdf
Instead of 800-page heavy volumes, Japanese textbooks are remarkably slim (often under 200 pages) but packed with dense, highly structured content. Before we discuss the "where," let’s discuss the "why
For those seeking these materials in PDF format, several educational repositories and translation projects provide access: Before we discuss the "where