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MANUFACTURING OF JAPANESE SABER BLADES

réparation sabre japonais

INTRODUCTION :

The armament of the Samurai consisted mainly of swords, spears, bows and rifles. But the weapon of predilection of the Samurai was the Katana.

Some swordsmiths were so skilled that some swords were given supernatural powers and sometimes even a name. Their manufacture involved not only a lot of skill and technical knowledge, but also a whole ritual. The blacksmiths prayed, bathed and purified themselves before making certain blades.

In Japan, six hundred traditional forges still manufacture, according to ancestral techniques, the famous combat sword of the Samurai and the Shogun. Curved blade about sixty centimeters long and with a single edge, the Katana has a role sometimes of pageantry, sometimes of real weapon. Weapon masters continue to teach the rituals of combat. Because by handling it, the student learns to "Forge his soul.

THE DIFFERENT TYPES OF STEEL ASSEMBLY FOR MAKING A KATANA BLADE:

It is known that the blades of sabers are made of laminations of several different metals, whether they are hard steels (Hagane), intermediate steels  (Kawagane) or soft steels (Shingane).

 

In addition to blades made with a single folded steel, high quality Japanese swords are also composed of different distinct layers of different types of steel (more or less hard).

 

This manufacturing technique uses different types of steel, to accentuate the desired characteristics in different parts of the sword, beyond the level offered by differential heat treatment (Tempering).

 

The steels used have different mechanical properties​ and that is by putting together different shades (The Shingane (Soft Steel),the Kawagane (Intermediate Steel) and theHagane (Hard Steel),that we obtain a blade that is both resistant andsharp.

Steel is iron containing carbon: the more there is, the harder the steel. Most blacksmiths in Japan work with a special form of steel called Tamahagane. This steel is produced almost exclusively  by a simple furnace, called Tatara, in Yokota, Honshu. NBTHK (Nihon Bijutsu Token Hozon Kyokai) is in charge. This "Society for the preservation of the Japanese art sword" was founded in 1960: it studies and preserves  ancient blades, and it organizes very important competitions every year for blacksmiths, polishers , scabbard makers and metal engravers\sculptors.

The principle of Tatara  is based on the propensity of iron, heated to very high temperatures, to combine with nearby carbon to produce steel. In a Tatara, coal will provide this carbon. Despite the efficiency of the furnace, the Tamahagane obtained is relatively coarse and the blacksmith must refine it by hammering to reduce the carbon content and make it into a metal that can be used to forge a sword.

 

ASSEMBLIES: 

There are almost an infinite number of ways steels could be joined, which often vary greatly from smith to smith. Typically the harder steel bar is hammered, stretched and bent into a "U", then the very soft base steel is inserted into the "U". Then they are forged and hammered to weld them together, while giving the basic shape of the blade. At the end of the process, the two pieces of steel are fused together, but retain their differences in hardenability. The most complex types of construction are generally found on older blades, with the vast majority of modern weapons being comprised of a single section or at most two or three sections. Another way to proceed is to assemble the different parts into a block, by forging and welding them together, then stretching the steel to make a blade, so that the different steels are correctly distributed. This method is often used for complex models, it allows to have a blade with which one can parry without fear of damaging the edge of the blade. For the Honsanmai or Shihozume types, pieces of hard steel are added to the outside of the blade in a similar manner. Shihozume and Soshu types are quite rare.​

The different types of blends that can be found, the Maru, the Soshu Kitae, the Kobuse, the Sanmai, the Tamahagane, etc.

KITAE: THE FORGE​

The forging of a Japanese sword blade involves a large number of steps. The blacksmith improves the quality of the metal both by compressing it to remove impurities and by selecting the pieces of metal based on their hardness characteristics.

​​The stages of making a Japanese sword:

​The first stepconsists of taking each end of the TAmahaganand flattening it into patties 5 to 7  millimeters thick and about 10 to 20 cm in diameter. Each of the cakes is red-hot and then plunged into cold water. This cake thus soaked is broken again into small cakes of 4 to 6 centimeters long.​

Each wafer is carefully examined on its edge, those which break easily and whose break presents a greyish grain are strongly carburized (and will be used to manufacture hard steel), those which present a white grain are weakly carburized (and will be used to manufacture the central part of the weapon containing the flexible steel).​

The second stepconsists of making at least two bricks from these pancakes. Each of the bricks is flattened at high temperature and broken into small pieces. This step, repeated several times, is used, among other things, to remove impurities from the metal and to distribute the patties according to their hardness.​

Once the result is judged to be suitable, the blacksmith remakes a brick which he will fold many times.

​ The bricks are laminated individually, a good fifteen times, to purify the metal. According to the blacksmiths, the sheeting can go up to 32 000 layers, in fact, the metal bar is hammered, lengthened, then folded on itself 23 times in accordance with tradition, then these layers are intimately welded together in the forge by balanced hammering on each side.

​ The result of this step will only be visible later: this is what will determine the Hada (Grit of steel). Of course, the method changes depending on the type of Hada you are looking for, but each school has its own techniques, which allows us to differentiate them. Contrary to a widespread legend, the number of bends is limited because otherwise the metal would be too condensed and would lose its flexibility.

​ Once the different bricks have been laminated enough times, the blacksmith assembles them according to the desired pattern. He welds these different parts together and lengthens the whole.

Once the blade is stretched and considered ready, the smith prepares his blade for tempering.

TSUCHIOKI: THE PREPARATION OF HAMON

The Hamon is the line on the sword that separates the tempered part (Yakiba) from the rest of the blade. Hardening is very important because only hardened steel can be sharpened and then retain its sharpness.

But if the whole blade was like this, it would be too brittle for combat. The characteristic of the Japanese saber is a hardening of the only cutting part, thus preserving in the body of the blade a flexibility which allows it to absorb shocks and withstand twists.​

​ The problem for the blacksmith is twofold: first, the cutting edge must be hard (but not excessively), and this will depend on the temperature of the forge, the carbon content of the steel, and the the soaking method.

​ Secondly, a Japanese sword must conform to the aesthetic canons of tradition. The transition zone between the hard, milky part of the cutting edge (martensite crystals) and the rest of the blade is not random: it is under the total artistic control of the blacksmith. It is an essential part of the final aesthetic rendering, and it is also a kind of signature, identifying if not the blacksmith, at least his school. 53 types of Hamon are listed.​

To perform the quenching and thus draw the Hamon, the blacksmith covers the blade with a mixture of refractory clay, charcoal powder and polishing stone powder (Omura), these last 2 components to avoid bursting heat sealer. This coating is carefully mixed: it must be free of bubbles or lumps. He then coats the metal using a spatula, gradually, thickening the gangue towards the back where it reaches 20 to 30 mm.

TOGISHI: THE POLISHER

The word Togishi designates in Japanese the craftsman "polisher of sword blades". 

The polishing of a blade is much more than a simple sharpening because it allows above all to put a blade back in its original shape, and to make its characteristics legible. This work is entrusted to a polisher specialized not only in polishing techniques, but also in the reading of blades as well as in the history of blacksmiths and traditions.​

Historically, current blade polishing techniques appeared late during the Meiji era. We can explain this evolution by the importation of electrical systems (So lamps) which allow the polisher to work with more consistency (The traditional technique required observation at sunset).

There are two major polishing techniques for a Japanese sword : Sashikomi and Hadori. According to the majority of polishers, the second style allows a better aesthetic approach to the blade by allowing a better swing between the Ji and the Ha.

In general, polishing a blade is done in two stages, the first called Ji-togi allows you to rework the shape of the blade and clean it of its rust. The second step (Shiage) is often referred to as blade makeup since it only changes the aesthetic side of the blade.

 

THE TOP TWENTY FORGE PROVINCES OF JAPAN:

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

THE BEST BLACKSMITHS IN JAPAN:

 

Japanese blades are renowned worldwide for their exceptional sharpness. Despite the abundance of documentation on this fascinating subject, the classification of blades and blacksmiths, established by Asaemon Yamada remains little known outside of Japan. Any hobbyist interested in Nihonto (Swords) or wanting to acquire a real Katana should consider this list.

Nowadays, this seal makes it possible to recognize the best Japanese blades, or Katana) or who wishes to acquire a real Katana must absolutely take this list into account.

Historically, Japanese swords were tested by expert swordsmen (Otameshigoyo). Their work consisted in carrying out, at the request of the blacksmith or his client, cutting tests, or "Tameshi-giri", on rolls of straw, bamboo stalks, helmets and pieces of armor, or on prisoners sentenced to death.

The best blades and smiths were thus classified into four categories :

  • The upper blades

  • The big blades

  • Very good blades

  • The good blades

The classification was modified many times with the arrival of new blacksmiths whose talents surpassed those of their elders. It also happened that Otameshigoyo had different opinions on certain blades. But the definitive version of the list of superior blades, which is still authoritative today, was established towards the end of the Edo period by Asaemon Yamada (Kubigiri Asaemon Token Oshigata). The Yamada family was a famous Otameshigoyo dynasty, and Asaemon Yamada was the most famous blade tester of his time.

His ranking of the top 14 smiths (Superior Blades) in Japanese history is as follows:

  • Nagasone Kotetsu :famous 17th century blacksmith from Fukui City.

  • Nagasone Okimasa :adopted son and disciple of Kotetsu.

  • Kanemoto Magoroku:famous 16th century blacksmith from the Mino region.

  • Kunikane Sendai :great 17th century blacksmith from the Sendai region.

  • Sukehiro Soboro :great 17th century blacksmith from the Osaka region.

  • Tadayoshi Hizen :famous 16th century blacksmith from the Nagasaki region.

  • Tadayoshi Mutsunokami :third generation disciple of Hizen in the 17th century.

  • Nagayuki Tatara :famous 17th century blacksmith in Osaka area.

  • Nagamichi Miyoshi :famous 17th century blacksmith in the Niigata area.

  • Hidemitsu Osafune :famous 17th century blacksmith in western Osaka area.

  • Masaie Mihara :famous 16th century blacksmith in Osaka area.

  • Motoshige Osafune :famous 14th century blacksmith in western Osaka area.

  • Kanemitsu Osafune :famous 14th century blacksmith in western Osaka area.

  • Kanesada Izuminokami :great 16th century blacksmith in the Mino region.

 

The Katana forged by the above blacksmiths are rare, even for some, almost impossible to find today. But you can find blades of less renown, worthy heirs of the Japanese forging tradition.

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