The Chugoku region (the westernmost part of Japan's main island, Honshu) is blessed with rich deposits of high-quality iron. Archeological evidence shows that iron swords, armor, tools, and agricultural implements have been produced throughout this area since the Kofun period (c. 250-c. 600). The prototypical Japanese sword, with raised ridge lines (J., shinogi zukuri) and a pronounced curvature, was first produced in this region during the Heian period (794-1185). The smiths working in the areas of Bizen (present-day southeastern Okayama Prefecture) and Hoki (modern western Tottori Prefecture) are especially well known.