Because of the insulation, the sword spine remains hot and pliable for several seconds, but then contracts much more than the edge, causing the sword to bend away from the edge, which aids the smith in establishing the curvature of the blade. Also, the differentiated hardness and the methods of polishing the steel can result in the hamon 刃紋 (frequently translated as "tempering line" but better translated as "hardening pattern"). The hamon is the visible outline of the yakiba (hardened portion) and is used as a factor to judge both the quality and beauty of the finished blade.