The katana was a battle-hardened weapon of the Samurai warriors of feudal Japan. It is an essential part of the Japanese culture, as well as an intangible cultural heritage. It is the result of over 1,000 years of swordsmithing tradition and practice. The katana is made of high-carbon steel that has been folded several times to create a layered impression. Its blade is sharp and durable, and the hilt and scabbard are usually made of wood. Swordsmiths carefully select their raw material and create a unique hamon, or differential line, in the blade’s metal to give it its characteristic shape and strength.
The process begins with a piece of tamahagane, or high-quality raw steel. The swordsmith heats the iron sand in a clay furnace, and the raw steel is hammered and folded repeatedly to form layers and remove impurities. This special forging technique creates the distinct curve that makes a katana so functional and unbreakable in a duel.
Once the smith has created a solid block of metal, he or she cuts a triangular section off to create what will become the kissaki (the blade’s tip). The shinogichi side of the sword is quenched (cooled rapidly in water) to harden it and make it strong, while the mune side is left to cool more slowly, which allows the steel to absorb shock.
After the scabbard, hilt and other fittings are crafted by another set of specialized craftsmen, the sword is polished with a series of finer stones to give it its final sheen. The smith may also add inlays or carvings to the blade, depending on its purpose and style. The keywords I will use are