The Katana or Samurai Sword is a weapon surrounded by mystery and folklore and is known around the world for its deadly sharpness and cutting ability. Historically the katana was the weapon of choice for the samurai of feudal Japan. The slender, curved blade with its single cutting edge gives the katana its distinctive appearance. Katanas have square or circular hand guard, a long grip for katanas for sale grasping with two hands, and a blade that is at least 60 centimeters long.
In absolute terms the Japanese word katana can be used to describe any single edged sword – it doesn’t even have to be of Japanese origin. However, in modern English usage the word katana refers exclusively to the sword of the samurai.
The katana first appeared in the Muromachi period (1392-1573) as escalating battle conditions required more effective weapons. The katana allowed the samurai to draw their sword and cut their enemies in a single swift motion which the new sword made possible because it is worn with the blade facing up.
The true beauty of the katana is in its expert construction. The Japanese had an understanding of metallurgy that was far more advanced than anything that Europeans were doing at the time. An authentic Samurai sword is made from a type of steel known as Tamahagane. Tamahagane is made from a mixture of high and low carbon steel, each of which has their own strengths and weaknesses. Steel with a high carbon content is harder and able to hold a sharp edge but is brittle and prone to breaking. Steel with a low carbon content is more malleable which makes it better for absorbing impact but also makes the edge easily blunted.
The genius of the traditional samurai sword maker was to combine both types of steel in a single weapon. This was typically done by making the outer edge of the sword from high carbon steel and the inner core from low carbon steel. The process of creating a single sword from two pieces of metal was done by making a U-shaped bar from high carbon steel and putting a length of low carbon steel into the U and hammering them together into a single piece of metal. Over a period of several days the piece of combined steel is heated, folded, and hammered. Generally speaking the katana was folded a maximum of 16 times before being hammered into the basic shape of a sword.
This process forces impurities out of the metal and also creates microscopic imperfections in the molecular lattice adding strength to the metal. That’s difference between forged and cast metal, forged metal has been hammered into shape and is much stronger than cast metal which has only been made molten and poured into a form (cast) and allowed to harden.
At this stage the katana would have had little or no curve which was actually created with an ingenious system of quenching. This was done by using a clay slurry, the formula of which was unique to each sword maker, to insulate the blade in varying degrees. By putting a thicker coat on the spine and a thinner coat on the sharp edge a heat gradient could be created. This caused the blades edge to be hardened by the quenching while the spine, with its thicker insulation, was allowed to cool more slowly and underwent less strain. The slow cooling would cause the spine edge to shrink slightly and over the course of several heating and quenching cycles would create the gentle curve that is so closely associated with the Japanese katana.
Traditionally crafted Japanese katana are available today but they are prohibitively expensive with their costs exceeding many tens of thousands dollars in some cases. However, quality reproductions made with contemporary manufacturing techniques are available at reasonable prices from many places that sell martial arts supplies.