The forging process of authentic Japanese swords
Written by admin on October 11, 2009 – 12:03 am -Through the histroy of the samurai, the forging process used in the creation of authentic Japanese swords is as much an art form as it is a science. The steps involved have been refined throughout this sword’s history however, even with all the technological advancements, much of the work involved remains very similar to the techniques developed by the original masters of this craft.
From selecting the most suitable raw materials to hand-polishing each Japanese sword, the sword making process is a process that requires substantial knowledge of the real Japanese sword's history. It also requires knowledge of the available materials and probably most important, the process requires patience. It is, after all, the fine craftsmanship and the attention to detail that make the Japanese sword the remarkable piece that it is.
In order to create authentic Japanese swords of the highest quality, it's important to begin with high-quality steel. It’s also important not to take any short-cuts. The highest quality Japanese swords are made using Tamahagane or iron sand. Few swords made from this traditional material are made outside of Japan.
Folding and hammering
Forge Folding, which is also known as kitae, is an important step in the sword-making process as it is what helps to remove impurities from the raw metals and helps to evenly distribute the carbon content. Folding also is what creates the subtle grain pattern in the metal which is known as the jihada.
To begin, the smith selects the metal pieces he feels are suitable for the project. High-carbon and low-carbon pieces are usually combined which makes the metal malleable. Combining the carbons is also what helps to ensure that the resulting metal is neither too soft nor too brittle.
Once the pieces have been selected, the smith welds the pieces to create the block about the size of a brick that will form the outside layer of the sword called the kawagane. Next, the block is hammered out and folded onto itself several times. This laborious hammering/folding process will be repeated as necessary, usually 10 to 14 times. The smith determines the number of times the folding/hammering process will be repeated.
The folding and hammering process creates thousands of layers within the block. These layers are where the unique patterns called jihada, an important visual component of the Japanese swords, start to develop each time the block is folded and hammered. The smith can influence the look of this pattern simply by folding the block in different ways, either always in the same direction, or in alternating directions, or by folding crosswise.
When the outer layer is finished it is then wrapped around the sword's inner layer, called the shingane. The two pieces are then welded together and hammered into a long, thin shape that incorporates a slight curvature. Various other tools including planes and files are used to refine the shape of the blade. The piece is rough polished and at this point, it begins to resemble a sword.
Forging the blade
There are 2 main goals involved in the Japanese swords forging process. First, in order for the Japanese swords to maintain its sharpness, its edge must be hard. The blade's metal must also be flexible in order to absorb shock. The way to create a metal that is both hard and flexible at the same time was figured out centuries ago and is still in use today.
Heat-tempering the sword's leading edge, a process called Hamon, produces the real Japanese sword's most notable and most highly sought after visual characteristic: the undulating line, or wavelike appearance, that runs the entire length of the sword edge. This characteristic that is unique to every Japanese sword edge is the end result of the way the metal has reacted to the intense heat to which it has been subjected.
To achieve this effect, as well as the sharp edge, the smith first creates a clay mixture of ash, water, clay and other ingredients. A thick layer of the mixture is applied to the spine side of the blade and the layer is thinned the closer it gets to the blade edge. All but the blade's edge will be encased in this clay mixture.
This clay mixture coating is actually what helps control the amount of heat the different parts of the blade receive. As the sword blade's metal is heated over red-hot coals, the crystalline structure of the blade’s metal undergoes change, and the metal produces a milk-white pattern.
A number of different patterns can be achieved, and the smith can control the pattern’s outcome by varying the way the clay mixture is applied to the metal. The resulting edge patterns have different names including Suguha which corresponds to a hamon that is very straight. A line with a zigzag pattern is referred to as a sambonsugi.
As soon as the metal reaches the appropriate temperature, which is determined by visual inspection, it is removed from the heat source and immediately immersed in a trough of water. Immersing the blade in water to cool, while the clay coating is still intact, is what changes the composition of the metal.
The metal beneath the thickest part of the mixture cools more slowly and results in a composition that is softer and more flexible. The edge, on the other hand, cools very quickly which results in a very hard composition. Remember, this is the ideal combination for a real Japanese sword blade. The smith will then inspect the sword and only if it meets his high standards will the sword be passed on to the final stages.
Polishing and mounting
Hand-polishing is what gives Japanese swords their mirror-like appearance. It is also what helps to bring out the blade’s unique characteristics. In particular, polishing brings out the intricacies of the hamon and the jihade, which are the focal points of the sword.
Polishing real Japanese swords takes years to learn and perfect. Those with the appropriate sword polishing skills typically will spend up to 30 hours painstakingly polishing each blade to perfection. Japanese sword polishers use a variety of graduating stone grits and an ample quantity of water to sharpen and shape the blade. Polishing helps bring forth the beautiful, one-of-a-kind crystalline pattern that is so desirable.
Since today's Japanese samurai sword is hand-crafted more for pleasure than for necessity, the final step is to mount the sword so that it can be admired by all.
The forging process of a japanese sword made by the huanuo forge.
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