Schools of sword craftsmenship appeared in the border area between Izumo and Hoki, and Bizen Province where there was good iron sand, and Yamashiro Province and Yamato Province which were the center of politics and culture.
良質な砂鉄がとれる雲伯国境地域や備前国と、政治文化の中心である山城国・大和国などに刀工の各流派が現れてきた。