Japan's halal certification system presents a distinctive case of non-state governance in a Muslim-minority context, yet its institutional architecture and cross-border recognition dynamics remain underexplored. This study analyzes non-state halal certification governance in Japan and its implications for global halal market access, with particular attention to the Halal International Trust Organization (HITO), a community-based certifier established in September 2024 by Indonesian Muslims in Japan. Employing a qualitative desk-study design, data were collected through purposive sampling of official documents, organizational publications, peer-reviewed articles, and media reports, and analyzed using thematic coding and source triangulation. Three key findings emerge: Japan's halal certification operates as a plural non-state governance system in which authority is dispersed across non-profit organizations, religious foundations, and community-based bodies, each deriving legitimacy through reputation and external recognition rather than state mandate; cross-border recognition — particularly through mutual recognition arrangements with Indonesia's BPJPH, Malaysia's JAKIM, and Singapore's MUIS — constitutes the decisive source of institutional authority, establishing the Indonesia–Japan recognition corridor as a structurally significant axis of bilateral halal cooperation; and HITO introduces a novel diaspora-led governance model oriented toward domestic inclusivity and SME accessibility, demonstrating that diaspora communities function as institutional actors and standard intermediaries rather than merely halal consumers. These findings extend non-state governance theory by identifying institutional specialization as the organizing logic of plural halal governance, and advance halal value chain literature by showing that local ecosystem building constitutes a foundational layer of halal market integration in Muslim-minority contexts. The study is limited by its reliance on secondary data; future research should pursue empirical validation through stakeholder interviews.