The Katana is one of the most important swords for Japan both in ancient and modern times. It was made for cutting and it’s semi-curved shape adapted to the warriors movements while attacking, making it easier to draw and hit than straight swords. It is also good at keeping the edge longer than straight ones.
The process of creating a Katana starts when the blacksmith hammers and shapes the raw material, called Tamahagane to its rough shape. Next he uses files to modify the shape. The Kissaki (piercing tip) is shaped and elongated, the Nakago (core) is struck to round and reduce thickness. The smith then forms a ‘Shinogichi’ or ridge line along the back of the blade.
When he’s satisfied with the basic shape he starts the heat treatment process, called Yaki-ire. He covers partially the blade with clay slurry, applying thicker layers to the spine and body of the blade than to the edge. The blade is then heated and quickly quenched in water, causing the different metals to cool at different rates. This gives the Katana a distinctive wavelike pattern, called Hamon, which fuses the rigidity of the blade’s sharp edge with its softer, more resilient spine.
After the heat treatment is done, the smith does a rough grind to refine and adjust the blade. Then he makes the scabbard, called Saya, with a soft leather, called Ito, or stingray skin, known as Sageo. The scabbard is then fixed with Mekugis, wooden pegs (two for a Katana used for Iaido). It can be decorated with a Menuki, a traditional ornament. The keywords I will use are