THE FORGING OF THE SAMURAI SWORD

A samurai sword, or katana, is a deadly work of art. It is considered by many to be the perfect killing tool. It is a dichotomy of beautiful craftsmanship and ugly utility. A katana is simply a curved blade sword, made in the Japanese style with traditional methods. Nice katana are made with traditional hand forging techniques that produce an extremely high quality blade.

So why is the katana so valuable? What makes it so sought after?

Well first, part of its value lies in in its deep history and tradition. When you hold a katana you are holding something that was perfected thousands of years ago and yet still stands the test of time. You are holding the physical manifestation of the best martial ideas. You are holding a piece of metal whose brother has toppled nations.

Another reason for the katanas value is its rarity. Even katanas made today are rare because there are only so many forges that can produce a high quality real sword. It is a dying art form, that Swords Of The East is happy to keep alive.

In the end, however, the real value of a katana sword is in the craftsmanship, structure and materials. A lot of these elements determine the price, as well as how long it takes to make the blade. 

TAMAHAGANE

One of the key features of the katana is the steel used to make it. There is only one type of steel that is used to create the katana. In the West we know it as Japanese steel, but in Japan it is known as “tamahagane.” Tamahagane translates to “jewel steel.” This steel is extremely pure but contains varying degrees of carbon. Carbon steel must be used to make any functional sword because stainless steel is too brittle and cannot withstand any abuse without shattering. The smiths who work with tamahagane want it to have varying amounts of carbon because when all is said and done they will be separating the steel into softer and harder versions, but more on this later.

Smelters of tamahagane today make it the same way it was made in ancient times. It is made in a type if furnace called a tatara. This furnace is built from clay at the beginning of each smelting. As the smelting process begins, the tatara is slowly filled with charcoal and iron sand. Shovel by shovel the ingredients are added every ten minutes or so, while the mixture is heated to 2,500F.Depending on the amount of steel the smelter desires to make, the process can take days.  At the end of the process, the tatara is destroyed in order to get to the steel lying within.

HARD AND SOFT

When they are smelting the steel they are careful to keep it from becoming molten. If the steel did become molten, too much carbon would be integrated within the steel, and the carbon would become too evenly dispersed. If the carbon does not disperse unevenly the smith will not be able to get the two forms of steel he needs to make the katana.

When the steel is cooled the smelter starts to break it apart. Depending on how it breaks, the smelter can discern whether the steel is high carbon or low carbon steel. A katana uses both high and low carbon steel. The high carbon steel is hard and brittle. It is the steel used to give the katana the much sought after razor sharp edge. On the other hand, the low carbon steel is softer and tougher. This steel keeps the katana from shattering, and allows the sword to absorb an impact.

The smelter picks out only the best tamahagane for katana making. The rest of the tamahagane is used for other purposes like knife making.

HAMMER AND FOLD

Once the swordsmith has the tamahagane he heats it until it is glowing and pounds it with his hammer into long slabs. These slabs are smashed. The smith then goes through the pieces and decides which ones are suitable as kawagane, the hard steel, and which pieces are suitable for shingane, the soft steel.

Once the pieces are separated the kawagane pieces are stacked together and the shingane pieces are stacked together. The stacks are wrapped in in paper, covered in clay and reheated until they glow almost white. Then, they are removed from the fire and pounded so that the pieces fuse into a block.

KAWAGANE

In order to make kawagane, the smith takes one of the blocks, heats it, pulls it out of the fire and pounds it into a steel bar. Then, he pounds the center of the steel bar until the bar is almost broken into two halves. He next hangs one half of the bar off of the edge of his anvil and pounds it down until it is hanging at a ninety degree angle. He flips the bar over and lays it back down on the anvil so that the half that was hanging is now facing upwards. Now he hammers the standing half back down onto the half lying flat to complete his first fold. Finally, he pounds the top piece in order to fuse the two halves back together.

Throughout this process the metal begins to cool and the smith must reheat it so that it becomes malleable once again. He has to be careful though, because each time he heats the metal he loses carbon. Sometimes, to get some of the carbon back, the steel will be rolled in ash.

The smith repeats the folding process multiple times, and as he does so contaminates are removed from the steel. The folding process also disperses the carbon in the steel more evenly.

Eventually, the smith will cut the bar into four equal pieces, stack them, reheat them, fuse them back together and begin a second folding process. This step further distributes the carbon. Finally, when the steel is ready it will have an even distribution of carbon throughout the resultant steel bar.

SHINGANE

For the shingane the smith uses the same process, except that he will likely have to do more folding than with the kawagane. This is because the higher carbon steel often contains higher amounts of impurities.

THE JOINING

Now that the smith has the two bars of metal he will use to make the katana he must join them together. The first thing he will do is hammer out the kawagane, so that it flattens and elongates to a little over a foot. Then he will bend the plate lengthwise into a “U” shape. Next, the smith shapes the shingane so that it will fit into the kawagane U. He inserts the shingane into the kawagane, leaving some of the kawagane U unfilled at the end. This end piece of the U will be seamed together to form the tip of the blade eventually.

At this point the process becomes more delicate, as a mistake at this point can ruin the sword. The smith puts the composite back into the forge where it is reheated. When the smith pulls the composite out of the fire, he must hammer it so that the shingane is completely covered by the kawagane, except for the open section of the U. There cannot be any gaps or pockets between the two metals or the sword will be ruined. They must fuse together perfectly.

THE BLANK

Once the metal is perfectly fused, the smith will begin to shape the sword. By heating and hammering he will lengthen and flatten the metal. Eventually the metal will begin to take the shape of the sword. By the end of this process the metal will be close to the final desired length and there will be a notched section towards the bottom which will separate the blade from the tang.

THE SHAPING

Once the smith has the blank it is time for his real skills to come out. He will have to now give the blade its basic shape. This process is very delicate. He must heat the blank just enough so that he can work with it but not too much that the two metal separate from each other. Further, as the blade gets thinner; the risk of breakage increases by hitting it too hard with the hammer. During this process, the smith only works an about 6” of the blade at a time in order to maintain the proper temperature.

This part of the forging takes great skill. The smith must know the correct amount of force to use when he is pounding the blade or it can easily become warped or twisted. He must be able to determine the temperature of the metal by its color. He must be able to work sure handedly and quickly. It is no wonder that in order to be allowed to craft katanas in Japan you must be licensed and have gone through years of apprenticeship.

THE GRIND

During the shaping process the tip of the blade was defined and the rest of the blade took on the basic shape of the sword. However, the sword is still very rough at this point. The smith will now take a metal planning device or knife and shave all of the any loose pieces or uneven sections from the blade. Next, the blade is filed and grinded until the katana takes on its desired shape. It is at this point the katana really looks like a katana, albeit still rough and unfinished. The lines are set and the surfaces are where they are supposed to be.

THE HAMON

At this point the smith will harden the blade of the katana and create the hamon. The hamon is the distinctive pattern you see on a katana blade. It often resembles a wave but can take multiple forms.

We have already discovered that the katana is composed of two different types of steel, soft on the inside and hard on the outside. However, even still, the blade edge is still too soft. In order to get the katanas legendary ultra-sharp edge it must be hardened further still. Yet, the rest of the blade must still remain softer so that the blade does not shatter in combat.

In order to accomplish this feat the smith uses a type of clay. The clay sticks to the blade because the blade was left rough during the grinding phase. This clay is basic clay with some additives like charcoal applied to it.

The smith coats the entire blade with the clay, but he applies different amounts to the back of the blade and the blade edge: less on the edge and more on the back. Because there will be less insulation at the edge of the blade it will harden more when heated. However, if the entire edge of the blade was hardened as such, it would be too brittle. Because of this, the smith adds thicker perpendicular lines of clay down the edge so that parts of it remain slightly softer. This helps give the hamon that wave effect.

With the clay added to the blade, the hardening process begins. This is the biggest test of the smith’s skills. He must really understand what he is doing or all of his work thus far will be worthless. He must heat the blade to just the right temperature, and he must do it so that the entire blade is heated evenly. He gauges this using only his eyes. Then, he will quickly dip the blade into water so that it quickly cools. He will then heat the blade to an even lower temperature and repeat the process. He may do this multiple times.

During the cooling process the edge cools faster, the back slower.  Because of this, even after the edge has finished cooling, the back is still cooling. When metal cools it contracts. Since the back continues to contract after the edge is cooled, the entire blade curves backwards. Although the blade was shaped with a slight curve, this final hardening gives the blade that genuine katana look.

When this process is complete, the clay is removed. Acid is applied to the hamon which serves to really define its design. The blade may need some adjustments to its curve and the like, but when that is done, the process of forging the katana is complete.

AFTER THE FORGE

With the forging completed, the katana will now undergo its transformation from merely a blade to a full-fledged sword. It will be polished, carved, signed and decorated. A collar of copper, a hilt and scabbard will be created for it. It will be designed to specifications and brought back to the smith. He has the final say about when the katana is complete.

In the end, it should be clear that the Japanese government mandated that all katanas be registered as a work of art. It is not just a blade: it is skill, sweat, patience, ingenuity, science, aesthetics and artistic vision given a physical existence. If you can’t see the value in that, you do not understand value.