Section V: Differences in Sword Construction Techniques This section will explain the differences between the various construction techniques used with Japanese swords. While some techniques were used with certain blades more than others, these are techniques which could, in theory, be applied to any blade. Regardless of method, all Japanese swords made with historical methods would be layered during the forging process and tempered to create the hard blade/ soft spine effect that is characteristic of Japanese sword construction.
Quick Recap Tamahagane (Jewel Steel) The high carbon steel, extremely hard steel valued at fifty times the price of normal steel for its lack of impurities.
Kawagane (Side Steel) The medium hardness steel that is used as an alternative to the hard steel of the edge or the soft steel of the core/ spine. Kawagane is more resistant to scratching than soft steel, and is less brittle than hard steel.
Shingane (Body Steel) The (relatively) soft steel used for the core of most Japanese swords. Shingane is layered through the forging process. Being softer than tamahagane, shingane is far more resilient. While very prone to scratching from edges made of harder steel, shingane is not brittle and is highly unlikely to shatter. Nonetheless, only an untempered blade (such as from cheap replicas) can actually be bent sideways to a substantial extent.