Aoya Kamijichi Historic Park

Aoya Kamijichi Historic Park preserves a large Yayoi-period (roughly 3rd century BCE to 3rd century CE) settlement site discovered during river-improvement works on the Chiyo River delta near Aoya in Tottori City. The waterlogged, oxygen-poor clay of the former marsh preserved organic material rarely found at Japanese archaeological sites, including wooden tools, farming implements, boat fragments, and more than 100 inscribed wooden tablets (mokkan) that provide direct written evidence of early Japanese administrative record-keeping. Excavated wooden pillars and postholes have allowed archaeologists to reconstruct the layout of raised-floor storehouses and pit dwellings, several of which have been rebuilt on their original footprints in the outdoor park area. The site was designated a National Historic Site in 2008 in recognition of the exceptional preservation of Yayoi-period organic artifacts, which are typically lost to decay elsewhere in Japan. The adjacent exhibition hall displays original wooden tools, pottery, and the mokkan tablets in glass cases organized thematically by artifact type: agriculture, woodworking, and writing. Curatorial material draws heavily on comparison with dry-land Yayoi sites to explain why wetland burial conditions make Aoya Kamijichi unusually informative. Conservation of the waterlogged wood required specialized freeze-drying and resin-impregnation treatment before display, work that continues on newly excavated material as further sections of the site are surveyed.