Interlinked Conservation of the Gendani Quarry Outcrop and Quarrying Knowledge for Tosa-suzuri Inkstone Production in Mihara Village, Kochi, Japan

Inkstones are traditional writing and drawing tools made from natural rocks, which are widely used in East Asian countries. Inkstone rock outcrops are the source and these outcrops represent notable sites associated with this traditional craft. In recent decades, quarrying activities have ceased at many inkstone quarries, posing two interlinked challenges: (1) conservation of sites affected by weathering, vegetation, and erosion, and (2) transmission of quarrying techniques through generations, which is often based on manual extraction methods. This study addresses these challenges through an investigation of Gendani Quarry in Mihara Village, Kochi Prefecture, Japan, a key outcrop for extracting Miharaishi slate used for the production of traditional craft Tosa-suzuri inkstone. However, slate quarrying ceased over 30 years ago. Field surveys and archival photographs revealed alteration of outcrop by the progression of weathering and past operation-related quarrying traces. In particular, past quarrying-induced fractures into the outcrop can be a pathway for rainwater infiltration, and thereby, progress the weathering along the fractures and limit the recoverable slate slab thickness, which becomes unsuitable for inkstone production. Additionally, we documented the traditional methods employed for Miharaishi slate extraction, including the use of quarrying tools and selection knowledge of suitable slates for inkstone production, by identifying quarrying traces on the outcrop and interviewing retired artisans. This study underscores the need for interlinked geological and cultural approaches to conserve quarries and associated craftsmanship. Sustainable utilisation of slate resources in collaboration with the local community can ensure the continuation of Tosa-suzuri inkstone craftsmanship in the future.