By repeatedly forging after folding back the steel struck and elongated, impurities such as sulfur, excess carbon and non-metal impurities are removed, and a strong and homogeneous steel is created.
叩き延ばした鋼を折り返しながら鍛錬を重ねることで、硫黄などの不純物や余分な炭素、非金属介在物を追い出し、数千層にも及ぶ均質で強靭な鋼へと仕上がっていく。