Relational expertise at the policy–practice interface: shido shuji as non-school-based teacher educators for culturally linguistically diverse students

Introduction Culturally and Linguistically Diverse (CLD) students' learning cannot be supported by individual classroom teachers alone; it requires system-level professional learning, institutional coordination, and mediation between policy and classroom practice. However, little is known about how non-school-based actors who support teachers develop the expertise needed to mediate these processes. This study repositions Japan's shido shuji as non-school-based teacher educators working at the policy–practice interface in the education of Culturally and Linguistically iverse (CLD) students. We conceptualize their expertise as relational: recognizing and mobilizing others' expertise, aligning purposes, and translating administrative categories into usable teacher learning and school routines. Methods Using constructivist grounded theory, we conducted semi-structured interviews (February 2024–September 2024) with four municipal shido shuji selected via criterion-based purposive sampling (city size and CLD concentration varied). Transcripts were analyzed through line-by-line and focused coding, constant comparison, memoing, and diagramming. Following Charmaz, we sought theoretical sufficiency, ceasing recruitment when additional data no longer added analytic purchase. Results A staged process of professional growth was observed: (1) first-year conflict and exploration, in which short rotations, weak handover, and prior-year budgets constrain shido shuji to transmissive roles; (2) turning points through relational capital (school observations; ties with university faculty and veteran teachers) that seed training design as a structured site of translation; (3) re-articulation and creation, where prior teaching commitments (e.g., career guidance, language access) are re-purposed into local designs—advisor systems, training foci, intake/assessment protocols; and (4) synchronization and conviction, as plans and budgets align from year two, consolidating identity as teacher educators. Core to these stages is relational expertise enacted across organizational boundaries. Institutional vulnerabilities—short tenures, person-dependent operations, and timing constraints—render this expertise contingent and may delay CLD-specific pedagogy and assessment. Discussion Read alongside international work on coaches, mentors, school–university teacher educators, and boundary objects/third spaces, our results position shido shuji as boundary-spanning teacher educators and illuminate how central–local governance shapes teacher education for CLD classrooms.