History of Sword Making in Japan
The history of knife making is inextricably linked to the history of sword making and many of the skills used today in the manufacture of the finest kitchen knives have evolved from the techniques developed and used to create the world’s most famous swords.
The fact that sword makers never considered their swords simply as weapons is what separates Japanese swords from those made in other countries. Not only did the sword makers pursue perfection in a sword’s practical function as a weapon, they also pursued the sword’s aesthetic beauty.
The curved blade so synonymous with Japanese swords was developed from the middle of the Heian period (800AD). Swords produced prior to that time were straight and called Chokuto. Changing battle style throughout different periods resulted in subtle changes to the curvature of the blade. By observing the shape and characteristics of a sword it is possible to determine approximately when it was made.
In Japanese sword history Koto (old swords) refers to swords produced before the end of the Muromachi period and Shinto (new swords) refer to those produced in the ensuing Momoyama and Edo period. During the Shinto sword period the development of the nationwide trade and transportation networks lead to expanded commerce which allowed iron to be supplied to a much broader area. This resulted in swords being made in areas where no iron was produced and explains why the swords from the Edo period have an almost uniformed quality regardless of where they were produced. On the other hand, those produced in or prior to the Muromachi period show distinct characteristics because the iron used came exclusively from the limited local area where the sword makers were based.
Swords are generally made of a relatively soft core iron surrounded by a much harder skin iron. A bar of iron made from the above two types is hammered and stretched until it 
takes a form of sword. The final step in the sword making process is tempering which greatly strengthens the sword. In this process a heat resistant clay paste is applied to the blade surface. Clay on the cutting edge is thinner than that which is applied to other areas. The coated sword is heated at between 800° to 1,000° Centigrade until it becomes a burning red color, and is then immediately immersed in cold water. The cutting edge cools rapidly while the rest of the sword takes longer to cool resulting in the cutting edge having a much harder quality. The clay coating results in various temper patterns for which Japanese swords and knives have become so well known.
Works of the Soshu School based in Kamakura and represented by the master sword makers Goro Nyudo Masamune and his premier student Goh Umansuke Yoshihiro contain a very particular type of temper line famed for its beauty. The overall blade structure is indicative of the time of production while the temper pattern is unique to the individual sword maker or a particular sword school’s traits.
The Japanese sword was not simply a killing tool but an object of beauty that had well defined aesthetic qualities. In an old picture scroll (1311 ~ 1312 AD) a warrior is depicted holding and appreciating the beauty of his sword. This is evidence that the custom of appreciating the Japanese sword was already established as early as that time.
Samurai always wore Katana even when they were not in battle. Swords were their status symbol. In the Edo period when a Daimyo appointed by the Tokugawa Shogunate to govern local territories retired or died, it was customary to present a masterpiece sword to the Tokugawa Shogun. And when a Daimyo was first appointed as a local governor by the Shogunate a congratulatory sword was presented by the Shogun. In addition, when a Daimyo was consigned to work for the Shogunate a sword was often presented to the Daimyo by the Shogunate as recognition of his contribution.
The changing shape of the Japanese Sword
The Heian period (794 – 1185)
The Tachi made during this period reflects the atmosphere of the aristocratic culture and had an elegant and dignified form. Its shape at was generally slim and had a pronounced curvature tapering to a very small tip. It was worn slung from the belt with the blade facing downward. The average length of swords at that time was about 75 to 80 cm.
The Tanto (short sword) made during the Heian period had a more practical function and were probably considered disposable. Because of this there are few works remaining from that early time.
The Kamakura Period (1185 – 1333)
With the establishment of the Kamakura Shogunate the aristocratic culture shifted to a warriors’ culture which valued courage above all else and preferred a more simple and disciplined lifestyle. Such a trend caused a change in the sword structure, from the conventional elegant and feminine style to a powerful, masculine style. The changes meant that the blade showed a lot less tapering and while maintaining the curve, had the same broad width towards a larger tip. The sword also became thicker and had a very powerful structure.
From this period onwards, Tanto (short sword) production increased greatly. Both the width and the length tended to be slightly smaller in dimension, most were around 24 cm long.
During this period tempering and forging technologies gained remarkable improvement and the strong aesthetic consciousness of the sword makers was evident in all their finest works. The most famous master sword maker Goro Nyudo Masamune worked at this time in Kamakura. He brought quality and perfection and his style of workmanship gained nationwide appreciation. He enjoyed great fame and popularity and was master to many students, the most accomplished of which was Goh Umansuke Yoshihiro. Although Goh died in 1327 at the young age of 30 his master Masamune continued on to teach many more students and create many more swords for 10 years into the following Nambokucho period.
The Nambokucho Period (1333 – 1392)
After the fall of the Kamakura Shogunate a brief Imperial rule was soon disturbed by a struggle for sovereignty. The entire nation was split between the two powers upholding the Imperial families divided into the North and the South regimes. Japan was in a state of continual war and political confusion. At the same time threats from overseas, which began in the preceding period with the Mongol invasion, continued and consequently resulted in production of both large and long Tachi and Tanto.
The Tachi was made long and wide and had a very powerful structure. Some were longer than 90 cm and were worn on the back. These large Tachi were often shortened at a later date by cutting the tang, resulting in the loss of the makers’ signature. The Tanto were also made larger in width and were usually more than 30 cm long.
The Muromachi Period (1393 – 1573)
The military power controlling this period moved the nation’s capital back to Kyoto and there again arose a culture nurtured by the court nobles. Production of large sword swords ceased and the normal Tachi style returned. It is at this time the Katana (swords worn inserted in the waist sash with the cutting edge facing upward) came into existence, although the Tachi was still very much in use as a preferred cavalry weapon.
During the latter half of this period fighting tactics changed to large scale infantry operations requiring faster sword handling abilities. The relatively long Tachi slung from the waist sash required a troublesome pulling out action before a cut could be taken and so it was replaced by the shorter straighter katana.
These early katana were not much more than 60 cm long and curved only towards the tip. There was hardly any tapering of the blade width towards the point and the tang was made short to suit a one-handed style. Due to the large quantity of swords required during this period many were mass produced and of lower grade workmanship.
The Azuchi Momoyama Period (1568 – 1603)
The nationwide state of war ended with the rise of Oda Nobunaga who was then succeeded by Toyotomi Hideyoshi, who in turn was defeated by Tokugawa Ieyasu who paved the way to national unification. The Katana, just like paintings and architecture of this period, took on a grandiose form and the overall blade structure was made more powerful and in many ways replicated the style of the Tachi made during the earlier Kamakura and Nambokucho periods.
Also during this period many Tachi from the Kamakura and Nambokucho periods were modified by cutting them short and re-forging them into katana. Katana made during this period were referred to as “new swords” denoting the advances in iron material, forging technology and the renewed quality of the swordsmiths workmanship.
Edo Period (1603 – 1867)
Swords produced at the beginning of this period gained a shape considerably different from earlier works. They had a normal width shallow curve and a tapering towards the point. The overall length measured around 69 cm.
As time went on the nations peaceful state gave the Katana a different function, and its appearance became more significant than its practical quality. Engraving in the blade surface, which originally started as an object of faith, became simply ornamental and resulted in many decorative designs.
Then in the latter Edo period at the end of the Tokugawa Shogunate, with the threat of foreign invasions, the Katana once again became wide and long to form a sturdy and fierce structure and were also again subject to mass production.
The Meiji Restoration (1867 – 1912)
When the Tokugawa Shogunate finally fell and Emperor Meiji took the power the samurai were deprived of their old privileges – including the right to carry swords that had been the sign of their class. With the growing industrialization and militarism at the turn of the 20th century and the subsequent wars with Russia, China and the West once again made swords a necessary, although most of these were now mass-produced in factories.
A further blow to Japanese sword making came after the Second World War when the occupying American forces forbade the manufacturing of swords. Also at this time about 400,000 historically and artistically interesting swords ended up in the USA and the art of the Japanese sword was on the brink of extinction.
Luckily in 1953 the manufacturing of swords became legal again, and the almost dead tradition was revived. There were still old masters alive who could teach the next generation. Now there are some 250 working sword-smiths, producing swords matching the beauty and quality of even the finest works produced in the past.
Japanese Swords are today classified into the following date categories:
- Jokoto (ancient swords) – 795
- Koto (old swords) 795 – 1596
- Shinto (new swords) 1596 – 1624
- Shinshinto (new new swords) 1624 – 1876
- Gendaito (contemporary swords) 1876 – 1953
- Shinshakuto (modern swords) 1953 –
