The Katana is a curved, single edged sword originating from Japan, and are one of the nation's most iconic weapons. Originally used by the Samurai of Feudal Japan, the weapon has also come to be commonly known as a "Samurai Sword". The length of the blade is often somewhere between 60 to 73 centimeters in length. The metal of the blade is created from Tamahagane, a hard, high carbon steel for the cutting edge and sides, and the tough, low carbon steel for the core and back, giving the blade a hard edge, while allowing it to absorb blows without shattering. The gentle curvature of the blade adds to the weapons cutting power by focusing the force of the blow on a smaller area. This curve is achieved during quenching: the sword maker coats the blade with several layers of a wet clay slurry, putting a much thinner layer on the front of the blade. When the blade is thrust in water, the front of the blade cools more quickly and hardens, while the slower cooling in the back of the blade reduces lattice strain on the spine, causing the blade to curve backwards. The Katana was not designed at all for penetrating armor. It was designed to make quick and decisive slashes at weak points in armor. Specifically the throat. This required extreme speed and accuracy to wield. And that required an extreme amount of training and discipline to wield. It is generally considered to be one of the greatest sword designs ever.