Perched above the Yoshino River in the Iya Valley in Tokushima Prefecture lies a small museum filled with monstrous secrets. The Yokai Yashiki, or Monster and Stone Museum, tells the history of the many monsters, demons, and spirits that inhabit the region. Yokai are a class of monster unique to Japanese folklore, and the museum is filled to the brim with them. Papier-mâché representations and artifacts line the walls, along with maps showing where in the surrounding remote landscape these yokai have been spotted. Objects supposedly previously owned by yokai…