The Japanese national curriculum increasingly emphasises inquiry-based learning (IBL), requiring school librarians to support this process by providing curated book lists. While librarians often rely on existing examples, the diverse nature of IBL makes relevant cases scarce. To address this gap, we present an online social platform, BookReach, designed for Japanese school librarians to create, share, and adapt book lists for IBL classes. This demonstration paper introduces the platform’s architecture, which integrates a unit-based curation interface with community features for sharing and adapting ‘practice cases’. A usability study with 18 participants yielded an average System Usability Scale (SUS) score of 62.36. While indicating acceptable usability, this result, when combined with qualitative feedback, highlights the critical need for open metadata on book difficulty. We will extend the platform for more social features and support longitudinal studies of real-world curation practices.