Japanese sword

The katana (刀) is the Japanese longsword (daitō, 大刀), although many Japanese use this word generically as a catch-all word for sword. Katana (pronounced [katana]) is the kunyomi (Japanese reading) of the kanji 刀; the onyomi (Chinese reading) is tō. It refers to a specific type of curved, single-edged sword traditionally used by the Japanese samurai. The weapon was typically worn by members of the buke warrior class paired with the wakizashi, or short sword. The two weapons together were called the daisho, and represented the social power and personal honor of the samurai (buke retainers to the daimyo). The scabbard for a katana is referred to as a saya, and the handguard piece, intricately designed as individual works of art especially in later years of the Edo period, was called the tsuba.

It is primarily used for cutting (although thrusting is possible), and can be wielded one- or two-handed (the latter being the most common mode). It is worn with cutting-edge up. While the art of practically using the sword for its original purpose is now somewhat obsolete, kenjutsu has turned into gendai budo - modern martial arts for a modern time. The art of drawing the katana is iaido (also known as battō-jutsu or iaijutsu), and kendo is an art of fencing with a shinai (bamboo sword) protected by helmet and armour, additionally, iaijutsu is an older style of battle field type fencing. Old koryu sword schools do still exist (Kashima Shinto Ryu, Kashima Shin Ryu, Katori Shinto Ryu).

See also tsurugi, tachi, wakizashi, tsuba, saya, zanbatou, iaito, bokken, shinai.

The Sword as a Mystical Object

Although the samurai classically carried or had access to many weapons (a bow and spear, at the very least, in addition to their blade(s)), only one was considered the soul of the samurai: the katana (or tachi). The Japanese pinned an extraordinary amount of value on the sword. For much of Japan's history, only samurai were even allowed to carry swords, and a peasant carrying a sword was enough reason to kill the peasant and take the sword.

Much of early Japanese culture revolved around swords. Elaborate methods for carrying, cleaning, storing, sharpening (or not sharpening), and swinging the sword evolved from era to era.

For example, a samurai entering someone's house might consider how to place his sheathed sword as he knelt. Positioning his sword for an easy draw implied suspicion or aggression; thus, whether he placed it on his right or left side, and whether the blade was placed curving away or towards him, was an important point of etiquette. As for the host, his longsword was generally stored under the wakizashi on a low rack, curving upwards; if it curved downwards, or was stored above the wakizashi, that meant the owner expected he might have to draw it quickly - a mark of suspicion to any guest.

However, most samurai turned to their swords as third resort: a bow first, a spear next, and only then the sword. After all, drawing your sword was like letting your soul blaze free.

History of the Japanese Sword

Swords are critical in most feudal societies, and Japan was no exception. In the sixth century BCE the legendary emperor Jimmu Tenno conquered much of Japan. At the same time, the Japanese took inspiration for swords from the Chinese. Early swords were merely duplicates of Chinese swords, straight and double-edged, but the warring stability of the Asuka period promoted the advancement of weaponry.

The first recorded production of the curved, one-edged 'Japanese-style' sword (as opposed to 'Chinese-style') is around 900 CE, but they had been in use for a significant time before that. According to legend, the Japanese sword was invented by a smith named 'Amakuni' in 700 CE, along with the folded steel process. It is at this time that the term samurai came into being.

By the twelfth century, civil war erupted after a long period of decadence. For five centuries, Japan had its own dark ages, marked by continuous, brutal wars. The War of Onin (1467-1477) revolutionized Japanese armour, and weapons hit a plateau of quality considered to be superior to those made even today.

During the Muromachi period, bloody wars were the norm, but the indolent shogunates also put a high value on art and culture, so the islands did not descend into barbarism. In fact, the swords from the middle of this era are considered the peak of swordcraft. However, as time progressed, the craft decayed under the withering pressure of guns, which rendered swords obsolete.

Swordmaking continued to decline in the early part of the Edo period, since there were fewer wars; however, art leapt forward, leading to beautiful engravings and decorations for weapons. Then, under the isolationist Tokugawa Shogunate, guns and gunpowder were increasingly restricted and removed from circulation. By the middle of the eighteenth century, most young Japanese had never seen a gun, let alone actually seen one fired.

The power of the samurai (and the quality of swordmaking) had nearly disintegrated under the power of guns, but they came out of the struggle with a fierce devotion to their ancient ways and an eye for the past. Samurai were strong during the Edo period, and the almost-lost art of sword smithing revived, slowly but surely. Nearing the end of this period, swords had recovered enough quality that they were no longer referred to as 'shinto', but the more respectful 'shin-shinto'.

Japan remained in stasis until Matthew Perry's arrival in 1853 and the subsequent Convention of Kanagawa forcibly reintroduced Japan to the outside world; the rapid modernization of the Meiji Restoration soon followed.

The Haitorei edict in 1876 all but banned swords and guns, crippling the samurai class. However, an uprising against this edict and the military rulership resulted in an explosion of nationalism and support for an emperor who had previously been mostly a figurehead.

By World War I, Japan was on par with global powers in its military might. However, this also marked the beginning of the end for samurai in general, for guns had returned. It also marked a time of decline in sword manufacture, as katana were replaced by gunto: cheap sabers for navy officers.

Under the United States occupation at the end of World War II the samurai class was disbanded completely and swords banned; . The only swords which were allowed to remain were artistic treasures, which could not leave the museum or temple.

Due to this disarmament, as of 1958 there were more Japanese swords in America than in Japan: American soldiers would return from the Orient with piles of swords, often as many as they could carry. The vast majority of these 100,000 or more swords were gunto, but there were still a sizable number of shin-shinto.

This symbolized the final blow to the power of the samurai in the recent centuries. However, swordcraft has since resumed, although as a cultural phenomenon rather than a war-based one.

Classification of Japanese swords

All Japanese swords are manufactured according to this method and are somewhat similar in appearance. What generally differentiates the different swords is their length. Japanese swords are measured in units of "Shaku". One shaku is approximately equal to 12" or 30 cm.

A blade shorter than 1 shaku is considered a tanto (knife).
A blade longer than 1 shaku but less than 2 is considered a wakizashi (short sword).
A blade longer than 2 shaku is considered a 'daito', or long sword. This is the category 'katana' fall into. However, the term 'katana' is often misapplied: a sword is only a katana if it is worn blade-up through a belt-sash (commonly accompanied by a wakazashi or tanto). If it is suspended by cords from a belt, it is called 'tachi'.
Abnormally long blades, worn across the back, are called 'no-dachi'. These are rare, usually encountered only in fiction.
It should be noted that there are many varieties of wooden practice blades, including those made out of wood ('bokken') and those made out of bamboo (often used for Kendo practice, usually referred to as 'shinai').

That's how you call them by size, and here is how you classify them by date of manufacture:

before 900: Straight and two-edged, like Chinese swords of the same era, these can safely be called 'Chinese Style'.
700-1500: A 'koto': these are considered the pinnacle of Japanese swordcraft. Early models had uneven curves with the deepest part of the curve at the hilt.
1500-1867: Derisively called a 'shinto', or 'new sword'. These are considered inferior to koto, and coincide with a degradation in manufacturing skills.
1867+: If made in koto style, these are called 'shin shinto', or 'new revival swords' (literally 'new new swords'). These are considered superior to shinto, but worse than koto.
1876+ (post-Haitorei Edict): Any mass-produced blade is derisively called 'gunto'. These often look like Western cavalry sabers rather than katana, although there are a lot of very recent (1970+) swords made to look just like katana, but mass-produced.

To classify the way a sword was worn:

before 1500: Most swords worn suspended from cords on a belt, blade-down. This style is called 'jindachi-zukuri', and all daito worn in this fashion are 'tachi'.
1500-1867: Almost all swords are worn through a sash, paired with a smaller blade. Both blades are blade-up. This style is called 'buke-zukuri', and all daito worn in this fashion are 'katana'.
1876+: Due to restrictions and/or the destruction of the Samurai class, most blades are worn jindachi-zukuri style, like Western navy officers. Recently (1953+) there is a resurgence in buke-zukuri style, but as swords are only allowed for demonstration purposes, this is largely irrelevant.

As a side note: swords designed specifically to be tachi are generally koto rather than shinto, so they are generally better manufactured and more elaborately decorated. However, these are still katana if worn in modern 'buke-zukuri' style.

As a further side note: most of the various kinds of spears could come with blades made in the same style as the Japanese sword. Although largely overlooked in Western literature, spears were the first resort of any samurai and most peasants, and the blades on the samurai spears were often of extremely high quality. However, despite this, the sword was still considered the soul of the samurai, not the spear.

Manufacturing

Japanese swords and other edged weapons are manufactured by an elaborate method of repeatedly heating, folding and hammering the metal. This practice was originated from use of highly impure metals, stemming from the low temperature yielded in the smelting at that time and place. In order to counter this, and to homogenize the carbon content of the blades (giving some blades characteristic folding patterns), the folding was developed (for comparison see pattern welding), and found to be quite effective, though labour intensive. Contrary to popular belief, this does not result in super-strength of a blade. The process of repeatedly folding the blade is performed in order to purify the metal.

The distinctive curvature of the katana is partly due to a process of differential quenching. The back of the sword is coated with clay, insulating it and so causing it to cool slower than the edge when the blade is quenched. This produces a blade with a hard edge and soft back, allowing it to be resilient and yet retain a good cutting edge.

This process also makes the edge of the blade contract less than the back when cooling down, something that aids the smith in establishing the curvature of the blade. As with other curved blades (e.g. sabers, scimitars, and machetes), this curvature makes the blade a more effective cutting weapon by concentrating the force of impact on a relatively small area; however, it decreases effectiveness as a thrusting weapon.

Manufacturing processes are described in greater detail in following subsections.

Composition

Traditional Japanese steel is considered to be one of the best for creating swords. The total composition varied from smith to smith and load to load of ore.

One more modern formula (from WWII) called for:

composition: 0.04% molybdenum
0.05% tungsten
0.02% titanium
1.54% copper
0.11% manganese
0.1% to 3% carbon
a varying amount of silicon
and a few other traces
Iron was the balance (made up the bulk of the steel).

The high percentage of carbon gave the blade strength while the silicon increased the flexibility of the blade as well as its ability to withstand stress. The katana was designed only to cut flesh, so the composition was not always adequate to effectively break armor.

Construction

The forging of a Japanese blade typically took hours or days, and was considered a sacred art. As with many complex endeavors, rather than a single craftsman, several artists were involved. There was a smith to forge the rough shape, often a second smith (apprentice) to fold the metal, a specialist polisher, and even a specialist for the edge itself. Often, there were sheath, hilt, and tsuba (handguard) specialists as well.

The most famous part of the manufacturing process was the folding of the steel. Steel was commonly 'folded', or bent over itself and hammered flat, as many as thirty times. This did several things:

It eliminated any bubbles in the metal.
It evened out the metal, spreading the elements (such as carbon) evenly throughout.
It created layers, which give the swords their unique grain.
Lastly, it strengthened the metal (perhaps by more evenly distributing the imperfections).

Generally, swords were created with the grain of the blade (called 'hada') running down the blade like the grain on a plank of wood. Straight grains were called 'masame-hada', whereas wavy grains were called 'ayasugi-hada'. Certain schools of construction had the grain running directly into the blade, resulting in a blotchy, ringed pattern. Although this weakened the blade, some samurai found it quite beautiful. If it resembled knotted wood, it was called 'itame-hada'; if it was splotched and burled, it was called 'mokume-hada'.

One of the core philosophies of the Japanese sword is that it has a single edge. This means that the rear of the sword can be used to reinforce the edge, and the Japanese took full advantage of this fact. When finished, the steel is not quenched or tempered in the conventional European fashion. Steel’s exact flex and strength vary dramatically with heat variation, and depending on how hot it gets and how fast it cools, the steel has vastly different properties. If steel cools quickly, from a hot temperature, it becomes martensite, which is very hard but brittle. Slower, from a lower temperature, and it becomes pearlite, which has significantly more flex but doesn’t hold an edge. To control the cooling, the sword is heated and painted with layers of sticky mud. A thin layer on the edge of the sword ensures quick cooling, but not so fast as to crack the sword steel (this makes the actual edge of the sword extremely hard martensite). A thicker layer of mud on the rest of the blade causes slower cooling, and softer steel, giving the blade the flex it needs (this makes the rear and inside of the sword into pearlite). When the application is finished, the sword is quenched and hardens correctly.

Then things got -really- complicated as the Japanese began experimenting with using multiple metals (all steel, but different carbon contents) in their swords at various points. You can see examples of these below:

Cross-section of katanas.

The vast majority of 'good' katana and wakazashi are of 'wariba-gitae' type, but the more complex models allow for parrying without fear of damaging the side of the blade. The last generally accepted model, the 'shiho-zume-gitae', is quite rare, but added a rear support.

The way they did the 'makuri-gitae' method was by using two steels, one folded more times than the other, or of a lesser carbon content. When both sections have been folded adequately, they are bent into a 'U' shape and the softer piece is inserted into the harder piece, at which point they are hammered out into a long blade shape. By the end of the process, the two pieces of steel are functionally the same piece, but with different rigidities. If the smith is performing han-sanmai-awase-gitae or shiho-zume-gitae, then pieces of hard steel are added to the outside of the blade in a similar fashion.

Okay, so now we've got a long iron stick. What makes it a katana?

This is the form of a katana:
Each blade has a unique profile, depending on the smith, the construction method, and a bit of luck. The most prominant is the middle ridge, or 'shinogi'. In the earlier picture, the examples were flat to the shinogi, then tapering to the blade. However, swords could narrow down to the shinogi, then narrow further to the blade, or even expand outward towards the shinobi then shrink to the blade (producing a trapezoidal shape). A flat or narrowing shinogi is called 'shinogi-hikushi', whereas a 'fat' blade is called a 'shinogi-takushi'.

The shinogi can be placed near the back of the blade for a longer, sharper, more fragile tip or a more moderate shinogi near the center of the blade.

The sword also has an exact tip shape, which is considered an extremely important characteristic: the tip can be long (o-kissaki), short (ko-kissaki), medium (chu-kissaki), or even hooked backwards (ikuri-o-kissaki). In addition, whether the front edge of the tip is curved (fukura-tsuku) or straight (fukura-kareru) is also important.

A hole is drilled into the tang, called a mekugi-ana. This hole is to anchor the hilt, and some of the older blades have more than one due to the length of the blade.

Decoration

Almost all blades are decorated, although not all blades are decorated on the part of the blade you can see. Once the blade is cool, and the mud is scraped off, the blade has designs and grooves cut into it. One of the most important markings on the sword is performed here: the file markings. These are cut into the tang, or the hilt-section of the blade, where they will be covered by a hilt later. The tang is never supposed to be cleaned: if you do, you can cut the value of the sword in half. The purpose is to show how well the blade steel ages. A number of different types of file markings are used, including horizontal, slanted, and checked, known as ichi-monji, kosuji-chigai, suji-chigai, o-suji-chigai, katte-agari, shinogi-kiri-suji-chigai, taka-no-ha, and gyaku-taka-no-ha. A grid of marks, from raking the file diagonally both ways across the tang, is called higaki, whereas specialized 'full dress' file marks are called kesho-yasuri. Lastly, if the blade is very old, it may have been shaved instead of filed. This is called sensuki.

Some other marks on the blade are aesthetic: signatures and dedications written in kanji and engravings depicting gods, dragons, or other 'acceptable' beings, called horimono. Some are more practical, grooves for lightening and extra flex. Grooves come in wide (bo-hi), twin narrow (futasuji-hi), twin wide and narrow (bo-hi ni tsure-hi), short (koshi-hi), twin short (gomabushi), twin long with joined tips (shobu-hi), twin long with irregular breaks (kuichigai-hi), and halberd-style (naginata-hi).

Polishing

When the rough blade was completed, the blacksmith would turn the blade over to a polisher, whose job it was to polish the steel of the blade to a glittering shine and sharpen the edge for battle. This takes hours for every inch of blade, and is painstaking work with different kinds of very fine stone. Early polishers used three types of stone, whereas a modern polisher generally uses seven. It almost always takes longer than actually crafting the blade does, and a good polishing makes a blade look better, while a bad polishing makes the best of blades look like gunto.

One of the ways which blades can be judged is by what this polishing reveals: the crystal-like qualities of the blade become quite visible, and the hamon (known in English as the temper line, where the sharp edge fades into the normal steel of the blade) shows the unique nature of the sword. Blades each are distinct in their hamon and the grain (hada) of their steel. The hamon, which is determined primarily by how the mud is applied, is often used as a kind of signature of the smith, above and beyond his own signature, and each tradition of sword smiths often has a particular style of hamon they prefer over all others. Hamon vary from straight to wavy to shaped like crabs or zigzags, and in their wandering they reveal important facts about the blade itself. A good polishing reveals what speed the edge was cooled at, from what temperature, and what the carbon content of the steel is. This is because it displays either nioi, which is a mix of extremely fine martensite with troostite (another type of tempered steel), or the more crystalline and obvious nie, which contains a lot of less fine martensite.

Furnishings

The work on the blade doesn't end here, though. From here it is passed on to a hilt-maker. Hilts vary in their exact nature depending on the era, but generally consist of the same general idea, with the variation being in the components used and in the wrapping style. The obvious part of the hilt consists of a metal or wooden grip called a tsuka, which can also be used to refer to the entire hilt. The cross guard, or tsuba, on Japanese swords (except for certain twentieth century sabers which emulate Western navies) is small and round, made of metal, and often very ornate.

There is a pommel at the base known as a kashira, and there is often a decoration under the criss-crossed wrappings called a menuki. A bamboo peg is slipped through the tsuka and through the tang of the blade, using the hole drilled in it. This anchors the blade securely into the hilt. To anchor the blade securely into the sheath it will soon have, the blade acquires a collar, or habaki, which extends an inch or so past the cross guard and keeps the blade from rattling.

The sheathes themselves are not an easy task. There are two types of sheathes, both of which require the same exacting work. One is the saya, which is generally made of wood and considered the 'resting' sheath, used in place of a more fragile and expensive sheath. The other sheath is the more decorative or battle-worthy sheath which is usually called either a jindachi-zukuri or a buke-zukuri, depending on whether it was supposed to be suspended from the belt by straps or thrust through a sash, respectively. Other types of mounting include the kyu-gunto, shin-gunto, and kai-gunto types for the twentieth-century military, but these swords were generally mass-produced and highly inferior, and few true Japanese swords are mounted in these styles.

Technique

The katana is designed for two specific functions, cutting and thrusting. Rather than slashing, chopping or slicing, the sword is made to cut through a target in a straight line. Cuts that do not cut all the way, or follow an arc on their way through the target can easily result in a warped or rolled edge.

There are other reasons for the curvature of the blade. Samurai were primarily cavalry, often charging on horseback into battle. A curved blade is much more effective in a cavalry charge than a straight one. This is the same reason curved sabres were given to officers and cavalry units in Europe and America in the 17th and 18th centuries.

While some people believe that katana and wakizashi were all the same, this could not be further from the truth. Tachi and no-dachi were also used, and katana themselves varied tremendously. They were often forged with different profiles, different blade thicknesses, and varying amounts of niku. Wakizashi were also not simply a 'scaled down' katana, they were often forged in hira-zukuri or other such forms, which were very rare on katana. Katana were more like an eastern equivalent of rapiers, one wouldn't often use a katana on an open battlefield (yari, naginata, yumi, and other such implements were preferred), and in battles, they served as a secondary weapon.

Myths

Many myths surround Japanese swords, the most frequent being that the blades are folded an immense number of times, gaining magical properties in the meantime.

While blades folded hundreds, thousands, or even millions of times are encountered in amateur fiction, there is no record of real blades being folded more than around thirty times. Note that with each fold made by the maker, every internal layer is also folded, and so the total number of layers in a sword blade is two to the power of the number of folds made; since the thickness of a katana blade is less than 2^30 iron atoms, going beyond thirty folds no longer adds meaningfully to the number of layers in the blade.

Furthermore, while heating and folding serves to even up the distribution of carbon throughout the blade, a small amount of carbon is also 'burnt out' of the steel in this process; repeated folding will eventually remove most of the carbon, turning the material into softer iron and reducing its ability to hold a sharp edge.

Some swords were reputed to reflect their creators' personalities, most famously those made by Muramasa and Masamune.

Kusanagi (probably a tsurugi, however) is a famous legendary katana.

Comparisons with European swords

It is a commonly-encountered article of faith that katanas are intrinsically superior to European swords. This belief is frequently bolstered by roleplaying games that assign superior statistics to katanas, and also by many movies. However, these claims are largely based on misunderstandings about the manufacture and role of European swords, and comparing the schools on their worst examples instead of their best.

Because Japan was an iron-poor society, making a sword was an intrinsically expensive undertaking; the supply of swords was limited, and so it was in the smiths' interest to make the most of the materials they could afford. Europe also had superlative swordsmiths; Toledo steel swords from Spain are one example of legendary quality swords from outside Japan. However, the greater availability of iron made it practical to produce cheap, low-quality weapons in large quantities. Where Europeans had the choice between expensive good swords and cheap bad swords, Japanese had the choice between expensive good swords or none at all.

European swords were also designed for different modes of combat. The katana's sharpness makes it an excellent slashing weapon, suitable for use against lightly-armoured opponents, but easily damaged when used against heavier armour. In this light, the relative bluntness of a good European sword is due less to the limitations of its maker than to the requirements of its use. Attempting to establish the superiority of the one over the other is ultimately meaningless without first defining the circumstances in which they are to be compared.