Smaller tools, manufactured by grinding a fragment of forged iron axe, were in use at the time of its emergence, but Japan made an iron axe called Fukurojo-Teppu (literally 'bag-shaped iron axe,' hollow structured iron axe) emerged in northern Kyushu by the first half of middle period and it gradually spread around western Japan.
出現当初は鍛造鉄斧の断片を研ぎ出して小型の工具などとして使っていたが、中期前半までには北部九州で袋状鉄斧と呼ばれる列島製の鉄斧が出現し、徐々に西日本一帯へと波及していった。