Written by Jeremiah Bourque.

Cover and sword construction graphics by Andrew Adams.

Introduction

Historical 日本刀 ( “nihontou”, lit. “Japanese swords”) are not just pieces of art, but finely tuned, exquisitely crafted weapons of war.

This short book is a celebration of the craftsmanship and dedication that went into the creation of these exquisite blades. One can simply look at these weapons and appreciate them for how they look, but knowing what lies under the surface is even more compelling. Together, the two form a strong foundation for true appreciation of the Japanese sword.

Japanese swords are said to be the soul of the warrior. They are also said to hold the soul of the swordsmith. This should not be misunderstood by taking it too literally; it is largely a figurative expression. Nonetheless, a reader who comes to comprehend the effort and skill required to forge these blades will understand how the sword truly contains a piece of the soul of its smith, for the sword reflects the qualities of his spirit.

I hope you will enjoy this book. Thank you very much.

- Jeremiah Bourque

Section I: The Creation of a Japanese Sword

1. The Birth of Hagane (Steel)

Japanese sword construction begins with the most basic of raw materials: satetsu (砂鉄), literally “iron sand.” As the name implies, this is iron-rich sand found in abundance in Japan. By contrast, actual iron ore is a scarcity on the Japanese islands.

In modern times, researchers have found these iron sands to be nearly devoid of the impurities that weaken final steel products. Thus, what began as a historical accident and an invention born of pure necessity evolved into the production of steel superior to that smelted elsewhere.

Today, virtually all steel outside of Japan is produced from iron ore (and therefore includes additional impurities), but Japan continues to use iron sands for producing steel for extremely refined tasks. For example, Kai Industries is a leading manufacturer of surgical blades made from steel produced from iron sand.

Traditionally, hagane ( 鋼 ), or steel, was produced using a tatara ( 鑪 ), a furnace named for the word for “foot bellows” (also “tatara,” kanji: 蹈鞴). That is, the tatara is a furnace with a foot-operated bellows used to add air – and therefore oxygen – to the fire to further raise the temperature. Producing steel by this method is known as tatara smelting (たたら製鉄).

2. Selecting the Proper Hagane

The traditional tatara furnace fared no better than similar furnaces all around the world. That is to say, the process was unreliable; temperature fluctuations resulted in inconsistent carbonization of the iron. Some of the resulting metal alloy was wrought iron, iron with a very low carbon content; some was pig iron, with such a high carbon content that the metal was exceptionally brittle.

Only a master smith, relying on long years of experience and the traditions handed down from master to apprentice for centuries, can reliably choose the pieces of hagane (鋼), or actual steel, that are useful for the construction of a Japanese sword. In most cases, this is not a single grade of steel; multiple grades are profitably employed, as we will see later.

Incredibly, master smiths differentiate steel pieces by their visual characteristics. This is truly what one may call a skill, rather than any kind of science. The mind ponders how much trial and error must have occurred before the smiths of old times got it right on a consistent basis and were able to pass down knowledge to their deshi (弟子), or apprentices, over the centuries.

As smiths go, being part of a long and illustrious tradition was certainly helpful to one’s reputation. Even so, a smith’s reputation was ultimately personal; a track record of verified success made the great smiths revered within their trades. After all, selecting the wrong pieces of steel would cripple all later steps.

Modern tatara smelting is more efficient and better controlled. While few people still make Japanese swords in Japan (most “Japanese swords” are made in China, from where the original techniques were imported), those that do are able to take a chunk of raw hagane, pound it to remove impurities and better distribute the carbon, and separate chunks into a pair of blocks suitable for sword manufacturing. While in old times, a smith would have his deshi do the pounding, a modern foot-operated pounding machine simply and effectively eliminates the need for extra manpower for this step.

3. Tamahagane, the Jewel Steel

In other parts of the world, sword forging via pattern welding employed a process of carbonization, adding carbon back to steel to bring the level of carbon up to standard, and forge welded this higher grade steel with lower grade, softer steel, resulting in a natural line (the “pattern”), even without the decorative finishing that became popular, turning the pattern into art. This is not, however, the process used in Japan.

Proper selection of the pieces of steel – first by the iron smith, then by the swordsmith – ensures that a high grade of very pure steel is the foundation of the remainder of the process. While the iron smith does his best, the swordsmith is ultimately responsible for final screening of the steel.

Once the proper pieces of steel are chosen, the smith and his deshi re-heat the steel and forge weld the pieces into a single block. (For the uninitiated, this means pounding the hot pieces together until they merge.) This work must be done briskly, lest the metal cool down and become unworkable. Pounding and re-pounding the steel into a rectangular shape distributes the carbon content evenly.

The hardest steel used in Japanese swords – that is, the steel always used for the edge – is known as tamahagane (玉鋼), or “jewel steel,” emphasizing its precious nature to both the smith and the end user.

4. Layers upon Layers

It is at this stage that the steel is folded into layers. The ultimate number of layers is the result of simple mathematics, as follows:

The piece of steel is folded. Result: Two layers. The steel is folded again. Four layers. Folded again. Eight layers. Folded again. Sixteen layers. ...And so forth.

Tamahagane was folded by good smiths between 12 and 16 times. Twelve folds would produce 4,096 layers. Sixteen folds would produce 65,536 layers! Twenty folds would produce a million layers, beyond which no folding would bring any conceivable metallurgical advantage.

So why layer the steel? Layers create two closely related effects.

The first effect is to allow the layers to bend at rates that differ very, very slightly when lateral (sideways) stress is placed upon the blade. Layering the steel creates resilience (toughness) that makes each part of the blade more likely to bend, and spring back, but not break. Broken swords are not much good to the warriors holding them.

The second effect is to allow the layers to cool at different rates during the tempering process. The faster steel cools, the harder it becomes; this is a product of the carbon that is mixed with the steel. The slower steel cools, the softer it remains. This creates a natural mix of hardness and flexibility. Kai Industries’ surgical blades, mentioned earlier, employ the same layering process today.

This development is impressive enough, but Japanese sword construction gets even more advanced.

5. The Core of the Matter

A cutting instrument, including a sword, must fulfill certain basic parameters.

1. It must have, and keep, an edge. 2. It must not bend beyond a certain limit. 3. It must not break.

Hardness solves problems #1 and #2, but #3 is a serious problem. The harder steel is made, the more brittle it becomes. This exposes the blade to chipping (when hitting something sufficiently hard) or simply breaking (when exposed to stress that exceeds its resilience). Layering helps, but Japanese swordsmiths felt they needed more.

For the moment, let us examine the so-called kobuse method of forging.

This method employs tamahagane for the edge and the sides of the blade. However, the back and interior – in other words, the core – of the blade are composed of softer steel, known as shingane (“body steel”), subject to the same process of layering.

Thus, Japanese swords forged in this manner have both the advantages of layering and a softer, more flexible core. The result is a sword that:

1. Keeps its edge.2. Retains its structure while cutting.3. Strongly resists breaking while cutting.

This creates, in a highly efficient, relatively lightweight package, a blade that properly achieves its primary duty: to cut, and cut well, without breaking from the stress of doing so.

Unfortunately, this method does have a serious drawback: edge on edge contact between Japanese swords is likely to chip both blades so much that the blades would have to be ground down to the core to eliminate the chip. This would create a portion of the blade that will not properly retain an edge, ruining the blade for any practical purpose. Thus, edge on edge parrying is not how samurai ever wanted to do business. If parrying is unavoidable, proper technique is to use the edge of the blade only. Ideally, the defender essentially slaps or swats the attacking blade out of the way. Knowing this, swordsmiths began modifying their creations to better resist damage from edge on side impacts.

So how does a swordsmith insert this core? It’s actually quite simple, really: the tamahagane is forged into a rectangle with a U-shaped opening in the back. The shingane is inserted into the slot. The two pieces are forge welded together and beaten and drawn out into the form of a blade.

This lays the groundwork for the final step in creating the blade itself: tempering.

6. Temper, Temper

All swords must be tempered to harden properly for real use. Tempering is heating a sword and cooling it quickly by quenching (submerging in liquid). This forces the carbon in the steel into a stressed state, giving it rigidity that will enable it to keep an edge.

Japanese swordsmiths apply clay to a sword to control the rate at which the blade cools when quenched. Also, the clay ensures carbon does not simply escape during this process. However, Japanese smiths went a step further: by applying different thicknesses of clay to the edge and spine (back) of the blade, respectively, they make the edge (coated with a thin layer) cool faster, while the spine (coated with a thick layer) cools slower.

The result of this process compounds the benefits of forging a sword with a softer core. The edge of the blade becomes very hard and strong, able to retain an edge befitting the marvelous reputation of these exquisite weapons. The

spine hardens, but does not become as hard, giving the spine a degree of springiness that immensely enhances the resilience of the weapon when swung in actual practice.

If you have ever looked at the side of a “real” Japanese sword, you have already laid eyes on what is called a temper line in the West. The Japanese have a considerably more refined term for it, calling it a hamon (波紋 ), or ripple. This is produced by adding a wavy line where the thin and thick coatings of clay meet, employing a substance that will not be removed through the course of grinding and polishing. Thus, what began as an unavoidable consequence of the process was, as in pattern welding, turned into a mark of creativity and an element of beauty.

The aforementioned surgical blades by Kai Industries employ the same kind of differential hardening to give its blades an extremely strong, cutting edge combined with the resilience and springiness to never break in action. This allows the surgeon to use a surgical blade like a samurai uses his sword: as an extension of his finely trained hand.

To summarize, a Japanese sword has three elements that make it so advanced:

Layers that add resilience. A mix of hard, cutting tamahagane and a soft steel core. Tempering that creates a hard edge and a springy spine.

This Triple Crown of sword forging is what makes the nihonto such a marvel of efficiency and effectiveness.

7. The Finishing Touches

A hardened blade has not only the edge and the spine, but the tang – the piece of metal over which the handle is fitted. The handle, complete with hilt, is usually fitted by a separate specialist. The tang contains a hole for a pin. This pin is driven through both the handle and the tang to hold the former to the latter.

Once a blade has been properly hardened, it must be sharpened up to the exacting standards of the samurai. The blade must be ground to a fine edge, but must also be ground to give the sword its edge.

Once the main grinding (rough polish) is finished, the tip must be carefully tapered and sharpened. While ideally, a samurai would want to use the edge and not the tip in battle, the tip is nonetheless an important part of the weapon.

Tapering is followed by the swordsmith engraving his mark onto the sword. The swordsmith is literally putting his name on the line when he does this. Engraving expresses the pride the smith takes in his hard work.

The sword is then passed to a polisher, a separate specialist who takes responsibility for giving the blade its final finish to bring out its true beauty.

Scabbards for Japanese swords are made with two pieces of wood that are fitted together and lacquered. Lacquer is a coating that adds color to the scabbard while protecting it from the elements. Between the scabbard and the hilt, a sheathed sword is protected as much as possible from the elements.

These steps complete the sword itself.

One quirk of Japanese steel of importance in these final stages, and for actual use, is that the steel is rich in oxygen. Oxygen inclusions are very soft compared to normal steel. Proper forging spreads these inclusions evenly, making them inconsequential for the durability of the blade. However, these same inclusions make the blade a joy to grind and polish.

Section II: How Swords Work

1. The Physics of Cutting

Before describing the different types of Japanese swords and variables in their construction, I would like to explain in greater detail why these swords are not only beautiful, but highly effective at their intended purpose.

First, think of a sword as a lever. The hand grips the handle of the sword (that is, the hilt). The sword has a pivot point (see illustration) around which the blade and handle both move. Obviously, the blade of the sword is longer than the hilt. Due to the balance point of the blade being further from the pivot point than the hand, the sword functions as lever.

All levers can work in one of two ways: trading movement for force, or force for distance. If a six foot pole is balanced after one foot, the lever’s ratio is 1:5. In other words, moving the long side of the lever five feet would move the short end of the lever one foot. However, moving a weight laid at the end of the short

side would require 1/5th of the force to lift compared to a 1:1 ratio.

So how can a long blade have any force behind it? Simple: the force of the blade is not simply the force of a flick of the wrist at any one moment. As the blade continues to move, it benefits from momentum; new force is added to the previous force, minus whatever is lost to gravity and the infinitesimal wind resistance faced by a marvelously sharp Japanese blade.

This momentum can only be achieved by swinging the sword with a certain amount of room. Thus, a sword of katana length cannot reach its full potential when used in cramped quarters. This is precisely why samurai used wakizashi (脇差), “side arms,” and tanto (短刀), literally “short blades.” A shorter sword has lower damage potential, but can reach that potential while swung in a much narrower space.

Momentum is important for cutting for one reason, and really, one reason alone: speed. Unlike attacking with a blunt instrument, like a hammer or wrench, cutting power is directly proportional to the speed of the blade. In practice, this speed is itself a product of the strength of the swing, and thus, the momentum put behind the swung sword. Once speed is accounted for, cutting power can only be maximized with a very sharp blade. Sharpness is really another word for reducing the area of the blade. By reducing the area, the force of the sword is distributed along a narrower edge; thus, the force is stronger in proportion to the substance being cut.

A good blade must also be hard enough to retain its edge during the course of cutting. Ideally, a blade retains its edge after the cut as well.

As discussed earlier, a sword is not effective if it breaks during the cutting process. Japanese sword design does a great deal to avoid breaks without compromising the efficiency and relative lightness and thinness of the blade.

In actual practice, cutting power also increases due to prolonged contact between the blade and the target area as the slice is followed through. The curvature of a Japanese sword allows the wielder to subtly draw the sword

across the target area.

Japanese swords are incredibly sharp and hard compared to human flesh. As a result, a single swing, reaching proper cutting speed, from a traditionally made katana is capable of inflicting spectacular wounds in a split second. The sword’s edge, being too sharp for mere human flesh to slow down to any considerable degree, continues to cut even after initial contact. A skilled practitioner following through with the entire slice will maximize the cutting power of the blade, potentially slicing through bone, or even completely bisecting an entire human torso.

Small wonder that the Japanese thought of their swords in spiritual, reverential terms!

2. How Armor Works

Samurai did not wear yoroi ( 鎧 ), or armor, just to look cool. (That was a convenient side benefit!) Samurai wore armor, first and foremost, because it worked.

Japanese armor may have had a bamboo “look,” and was lacquered like wood to protect it from the elements, but was nonetheless made of hagane (steel). Of course, this steel would not be tamahagane; nonetheless, armor was quite successful in halting cuts from katanas.

The key element in cutting is the difference in hardness between the sword and the target. An edge must have initial penetration, exploit that penetration through speed and momentum, and continue the cut until exiting the target material.

Armor blunts the initial penetration by having far greater resilience than human flesh. With this penetration lost, the edge is drawn across the surface of the armor, unable to cut effectively. If the armor was of equal hardness to the blade, the armor’s defense in depth – that is, distribution of the impact and cutting force throughout its interlocking molecular structure – would result in the blade quite literally bouncing off its target, just as rounds of too small a size bounce off the hull of a tank or a battleship.

If, on the other hand, the armor is of a softer grade of steel, the resilience and mass still prevents cutting beyond the barest of degrees, resulting in nothing more than a thin trail of disordered steel molecules along the surface. In other words, the cut leaves a scratch.

So, armor worked – when a katana struck armor directly. In actual practice, ordinary troops did not wear armor that was anywhere near as elaborate as the museum pieces that were once worn by daimyo, the provincial governors and one-time feudal warlords of Japan. A slice, or even a good nick, to an unprotected area would lead to a severe wound.

Section III: The Role of the Japanese Sword in History

Due to the aforementioned twin realities – that is, the power of the sword to cut, and the ability of armor to defend against it – the katana was not the primary weapon on the feudal battlefield. As a weapon, the sword labors under several disadvantages: it is shorter than the Japanese yari (槍), or spear/ lance; it does not deal well with armor; it cannot penetrate armor like a piercing weapon might; it does not have the long reach of a bow or, in later times, a firearm; and Japanese blades are not well suited for defense.

On the other hand, the sword’s ability to inflict grievous, instantly fatal damage was considered marvelous and awe-inspiring by the bushi (武士), or warriors, of Japan, both samurai and non-samurai. Also, the ability of armor to neutralize the sword only applies if the intended target is wearing any.

Consequently, the sword was a perfect weapon for dealing with people out of armor: in a private residence (though the shorter swords were often used for this rather than katana per se), on everyday streets, and so forth. Furthermore, this reality made the sword the perfect weapon against non-warriors should such a situation ever arise, either for self-defense (against robbers, for instance) or for settling a grudge. In turn, non-warriors understood that a Japanese sword could end their lives spectacularly and in a heartbeat, giving the sword a strong intimidation factor.

These characteristics, in addition to the aesthetic beauty of the better crafted blades, made the sword an unmatched status symbol for the samurai. I believe we can easily understand how samurai viewed the sword as the tamashii (魂), or soul, of the warrior.

Following the end of Japan’s Sengoku Jidai ( 戦国時代 ), or Warring States Period, internal battles in armor virtually died out. In the few battles that did occur, Western firearms technology played a significant role, making armor fairly useless anyway.

As this period came to an end, measures were taken to stratify Japanese society and stifle the extreme upward social mobility that characterized the period. Indeed, the ruler who instituted the first great “sword hunt,” Hideyoshi Toyotomi (豊臣秀吉), himself rose from lowly roots. Rather than seeing his own rise as a good thing for Japanese society in general, he appreciated all the more the ruinous impact upon the upper crust of society of letting people rise as he had done. Thus, non-samurai were stripped of the right to wear two swords, and only samurai would retain the right to wear two swords. This policy would remain in force until the Meiji Restoration in the middle of the 19th century.

What often escapes notice by Westerners recounting the sword hunt is that merchants and artisans (but not peasants) were able to wear one sword, the wakizashi, for self defense. On the field of battle, or outdoors in general, the katana is a far more versatile and dangerous weapon; thus, the katana has strategic military value whereas the wakizashi does not.

During the long reign of nearly complete peace, Japan eschewed foreign

adventures following a disastrous invasion of Korea by Hideyoshi himself. The Shogun, or General (in effect, military dictator) who truly established peace, Tokugawa Ieyasu (家康徳川), was a man in search of a “peace dividend” that would last many years. For better or worse, that is exactly what he obtained.

Without battlefield clashes, samurai relegated their armor to displays in the family home and walked about in kimono (着物), the expensive silk garments made famous around the world. Thus, either in a duel or a random attack, neither the samurai, nor their opponents, were wearing armor.

In such circumstances, the two swords worn by the samurai were spectacularly effective. In spite of draconian laws to maintain public order (Tokugawa’s legacy), samurai – the de facto backbone of that public order – did not always find swords to be relics of a bygone age, but sometimes used them to kill, and be killed.

Even so, the long peace and the cultural strength of the samurai caste (for that is what they now were) lent itself to the flowering of samurai culture. This was the era of the tea ceremony, of widespread study of swordsmanship, and of poetry and literature reflecting upon the values of bushido (武士道), the Way of the Warrior, and closely related, Zen Buddhism.

In this way, the katana became more than just a weapon in a warrior’s arsenal, but rather, a cultural icon. When renegade samurai resisted the Meiji Restoration, even to the point of wearing old-style armor obsolete on serious battlefields for many years, they were defending not so much a way of life, but an idea: the idea of the samurai as warrior supreme rather than as a cog in a modern army. They failed, but the samurai spirit nonetheless trickled down into the Japanese Army, where it would stiffen spines and lend itself to new service – directly for the Emperor – in Japan’s fateful wars to come.

Section IV: Types of Japanese Swords

1. The Katana (刀)

Originally, katana (刀) was a general term for “a blade” (a cutting instrument with a curved edge). However, we know from Miyamoto Musashi’s Book of Five Rings that by the time he wrote that book, the term katana had come to indicate curved Japanese swords of what was considered “normal” length for battlefield use. So, if anyone tries to tell you that this use of katana is a misuse, the Japanese started it first, so there.

Historically, a katana blade is between 23.6 inches and 28.7 inches in length (60cm to 73cm). This was not random variation, but rather, representative of a phase during the early 16th century (the early Warring States Period) when the length “shrunk” to the shorter length before “growing back” to the longer length later in the period.)

The “modern” katana – that is, the one identified as its own sword, and not as a generic term for “blade” – originated from the Muromachi period (which lasted from 1392 to 1573) as a result of changing battlefield conditions. Namely, existing blades couldn’t be drawn fast enough.

What we now call the “katana” since is a curved blade worn with the blade’s curve upwards rather than straight down. Instead of being forced to draw the blade straight up (like an Arabic scimitar), this allows the wielder to attack with the blade even while drawing the weapon. This trick is accomplished by pointing the top of the scabbard outward and drawing partially sideways. (This can be accomplished in part by tilting one’s own body.)

The katana is long enough to allow a human being of modest height (keep in

mind medieval Japanese people were not hugely tall on balance) to use strength and momentum to give the blade ferocious speed, giving birth to tremendous cutting power. The katana is also short enough to be used indoors (if not necessarily comfortably, depending on the exact surroundings), in cooperation with fast lateral footwork, and so forth. It is also light enough to be heavily controlled by the user for rapid changes of direction.

This blend of power and versatility has made the katana Japan’s defining sword.

Image by GxAce.

2. The Wakizashi (脇差）

The name of the wakizashi (脇差) is derived from the fact it was worn on the side for personal protection; thus, it is literally a “side arm.” Traveling the roads in old Japan was not an inherently safe enterprise, so even “ordinary people” wielded such swords for self-defense with regularity.

While not considered a battlefield weapon, the sword was considered a mix of shorter length and adequate killing power to qualify in later eras as the sword that never left the samurai’s side for any reason, even while temporarily handing over his sheathed katana when a guest at another’s residence.

Against an opponent wielding a knife, tanto, or similarly short (but dangerous) weapon, the wakizashi provided a length advantage while remaining extremely fast. Against a katana, the literal and figurative shortcomings of the weapon quickly become apparent.

Pairs of katana and wakizashi forged by the same smith at the same time were actually extremely rare, and therefore, very valuable. Most pairs were simply matched as well as possible.

Miyamoto Musashi invented a style wielding both the katana and wakizashi at the same time, using the threat of the latter’s blade to control the movements of opponents while the katana does the major offensive work. Even so, Musashi was an exceptional warrior who did not even wield his katana two-handed even with an empty off-hand. His teachings were dismissed as too difficult and too unique to use, and besides, few samurai in the post-Warring States era ever dueled to the death. Musashi’s legend left a far greater impact than the style he invented.

3. The Tachi (太刀)

The tachi ( 太 刀 ) is the type of curved sword that the katana eventually replaced. This sword was worn with the curve facing down. Also, the tachi had blades of 31 inches in length, rounded up (78cm).

Rather than being used on foot, tachi were cavalry weapons used very similarly to cavalry sabers employed around the world. The natural limitations of swinging a sword are altered when mounted on a horse; the power, speed, and momentum of the horse are directly transferred to a blade, making even one-handed use deadly to the opposition.

The tachi was used mainly for cutting down enemy foot soldiers. After all, foot soldiers were likely to have poor quality armor and to be vulnerable to attacks to the head, neck and so forth.

The Mongol invasion of Japan (which fortunately for Japan, ended in failure) demonstrated that the tachi was difficult to draw and use in close quarters, leading to difficult battles against Mongol horsemen. This led directly to the invention of the “katana” style sword.

4. Oodachi (大太刀)

The oodachi (大太刀) is an oversized long sword (tachi) and translates well as “great sword.” The blade would, on average, be 65 to 70 inches long (165-178cm), though no precise classification is possible across so many centuries. As the sheer length makes tempering more complex, relatively few were ever produced. Many were used purely as ceremonial weapons in religious services or on display.

On the battlefield, this weapon would be used on horseback; it certainly could not be used properly at close quarters. Despite the weight making the weapon difficult to use, the length and power (the horse’s speed and strength add to the blade’s effective power) made the weapon fearsome indeed.

Oodachi were often forged as exhibitions of a swordsmith’s skill. They were also a samurai fad during part of the post-Warring States “Edo Period.” This came to a crashing stop when the government outlawed production of blades beyond a set length (even for samurai).

5. The Nodachi (野太刀)

The nodachi (野太刀), or “field sword,” was essentially a longer version of the tachi, but not to the extent of the oodachi. The blade length was typically 48 inches (122 cm). Nonetheless, there is no clear dividing line between the nodachi and the oodachi, leading to a great deal of subjectivity and conflation between the two.

The key difference between the two was in its use. While the oodachi was employed on horseback, the nodachi was designed to be carried by a man on foot and used as an anti-cavalry weapon. While use indoors or in close quarters was virtually impossible, the “field sword” had its uses against cavalry. The weapon could even be thrown to great effect.

Several shortcomings restricted its use: the blade was more difficult to forge than a normal sword, the nodachi required more strength to wield properly than a regular sword, and spears or naginata type weapons were used in similar roles on the battlefield at a fraction of the cost.

In peacetime, the nodachi was worn on, but not directly from, the back. The sword was often a status symbol. It was famously wielded by Sasaki Kojiro against Miyamoto Musashi, unsuccessfully.

6. Tanto (短刀)

The tanto (短刀) literally means “short blade.” Rather than a sword, it is more of a dagger or tactical knife that lacks a katana-like curve. While the scabbard generally has a slight curve, the actual blade is straight. Blade length varies between 6 and 12 inches (15 to 30cm). Most tanto have a single edge and a tapered point. Indeed, the main purpose of the weapon is to thrust, not cut – though Japanese smiths habitually made these weapons very capable of cutting if required.

Tanto were normally carried by samurai, not commoners. Prior to the end of the Warring States Period, many samurai carried tanto rather than wakizashi as their back-up weapon. This was for a very simple reason; the tanto was far more practical for a man on a horse. The decline of cavalry, and then of war altogether, led to the wakizashi being adopted as the samurai’s second weapon.

Throughout this transition, tanto were carried by samurai women for self defense – as well as for suicide, should a grim circumstance arise where death was the better fate.

Tanto existed in many styles. One variety used modified tips from yari (spears), attaching them to a short wooden handle. As these tips were designed to pierce armor to begin with, these were very dangerous weapons at close quarters, even to an armored opponent. Other tanto were blades but with a reinforced cross-section to not break when penetrating armor. This easily explains the desirability of a tanto while on horseback. Even samurai who did not carry tachi or katanas would want a tanto sitting around, just in case.

7. Variations and Fiction

The so-called ookatana (大刀 ) is simply a katana of somewhat longer than standard length. Not all Japanese people were universally short, so some samurai might have wanted a longer blade to compliment longer arm length and maximize an advantage in reach while not compromising body mechanics.

The same kanji have been misread as “daikatana,” a mix of the phonetic (“on”) readings and the native Japanese (“kun”) readings of both kanji, and thus, a purely fictional mish-mash to come up with the idea of a big sword. This formed the title of a famously doomed Western video game that was designed and implemented as poorly as its title.

The so-called zanbato (斬馬刀) stands for “horse cutting sword,” but no such weapon existed in Japan. Rather, this is based on a weapon used at one time in China. In reality, the nodachi fulfilled this role in Japan as much as anything. However, fiction on both sides of the Pacific Ocean honors the idea of the weapon, even if the name is deficient in historical truth.

Similarly, the ninjato ( 忍者刀 ), or “ninja sword,” is a work of pure fiction. Supposedly, such a weapon could be drawn faster, but a straight blade would have compromised its cutting power. In reality, a ninja probably used a wakizashi like anyone else: a ubiquitous, completely legal sword that is deadly in close quarters. In the proper era, this would have been the “Saturday Night Special” of the day.

Image by Richard Stein.

On the other hand, the nagamaki (長巻), which translates as “long wrapping,” was quite historical; indeed, this weapon is said to have been used extensively by the famous/ infamous warlord Oda Nobunaga. The name derives from the fact that the weapon is simply a katana blade with a very long handle (equal to

the length of the cutting edge) wrapped around the tang, allowing the weapon to be used as a cross between a spear and a sword, with greater swinging distance to build up more speed (and thus, more cutting power). This weapon was used on foot as an anti-cavalry weapon, which fit well with Nobunaga’s modern tactics (including the incorporation of Western firearms to fight the great cavalry powers of his day, which were bitter rivals of his for domination of Japan).

A paired katana and wakizashi are known as daisho (大小), lit. “long and short” (as in, long and short swords). As previously mentioned, most daisho were not from the same batch, forge, or even smith or era; those that were made as a perfect match were highly prized.

As might be expected, Japanese sword making went through a period of sharp decline with the outbreak of relative peace. Old traditions handed down from master to deshi were being lost left and right. The “new swords” being made during this time were, to put it bluntly, junk compared to the old masters (and yet, still marvelous to hold and look at). A renaissance of quality created the swords that are literally called “new new swords” that brought standards up until the Meiji Restoration. Unfortunately, the quality never reached that of the old masters.

What few true masters carry on the same traditions today are formally recognized as “Living National Treasures” of Japan, and rightly so. Even so, we cannot but marvel at what the skill of the ancient smiths must have been like to put even these dedicated smiths to shame.

For a time, post-Meiji Japan shunned swords even for its army officers. This was discovered to be impractical; just as Western officers needed pistols on occasion, even if ordinary infantry carried only rifles, so did Japanese leaders benefit from swords. If nothing else, these swords served as a means to signal friendly troops, bolster morale, and lead bayonet charges, should such a need arise. (This also made leaders easier to identify by snipers, making these double-edged swords, figuratively speaking.) This need led to the creation of the gunto (軍刀), or “Army Sword,” using the latter-day association of the last character with “sword” rather than a generic “blade.”

Gunto were not katanas. Rather, they were based on the tachi design, and thus, were worn and drawn like military sabers the world over. Gunto before 1934 are considered “old gunto” (kyuu gunto, 久軍刀) while those during or after 1934 are considered “new gunto” (shin gunto, 新軍刀). While the “old” model greatly resembled Western sabers, the “new” models were meant to evoke an image of old Japan without confusion with the katana, which was, after all, the symbol of the samurai that the Meiji Restoration had abolished. Blade quality varied wildly; some gunto used blades transplanted from swords made by the masters. Of course, such swords were intended for top officers. Quality plunged during the course of WWII.

General MacArthur naturally had no desire to allow Japanese swords to remain in private hands during the American occupation following Japan’s surrender. MacArthur was convinced to make an exception for swords of great artistic value that had little in common with the army swords Americans had faced time and time again in the war. Military swords were liquidated on a vast scale; they were either sold to American servicemen at fire sale prices, or physically destroyed. This explains the glut of gunto at American auctions, gun shows, and so forth.

Today, replicas of Japanese swords are produced in various locations around the world, mostly in China (ironically, the origin of Japan’s highly evolved sword making techniques). Many of these swords are not folded, not laminated with softer metal cores, and not differentially hardened, thus making the blades useless as weapons. More expensive blades have some mix of these options, but blades made in real traditional fashion are rare and expensive.

At any rate, Japan only permits the ownership and, on a very limited basis, the new production of traditional Japanese swords as works of art. They are carefully registered and never, ever meant to be used as actual weapons. Rather, they are to be appreciated for their beauty and workmanship. One might imagine that the collectors appreciate the beauty of these weapons as weapons, and not just as being pretty to look at, but this is deep appreciation for a bygone era.

Outside Japan, authentic and replica weapons are known as “samurai swords” and are prized by weapons collectors. In recent years, some have been used in the commission of crimes; public and media outcry following a few small but spectacular incidents led the government of the United Kingdom to ban the sale and import of “samurai swords” on its territory. A country with extensive gun control cannot be expected to blush at a little sword control.

Section V: Differences in Sword Construction Techniques

This section will explain the differences between the various construction techniques used with Japanese swords. While some techniques were used with certain blades more than others, these are techniques which could, in theory, be applied to any blade.

Regardless of method, all Japanese swords made with historical methods would be layered during the forging process and tempered to create the hard blade/ soft spine effect that is characteristic of Japanese sword construction.

Quick Recap

Tamahagane (Jewel Steel)

The high carbon steel, extremely hard steel valued at fifty times the price of normal steel for its lack of impurities.

Kawagane (Side Steel)

The medium hardness steel that is used as an alternative to the hard steel of the edge or the soft steel of the core/ spine. Kawagane is more resistant to scratching than soft steel, and is less brittle than hard steel.

Shingane (Body Steel)

The (relatively) soft steel used for the core of most Japanese swords. Shingane is layered through the forging process. Being softer than tamahagane, shingane is far more resilient. While very prone to scratching from edges made of harder steel, shingane is not brittle and is highly unlikely to shatter. Nonetheless, only an untempered blade (such as from cheap replicas) can actually be bent sideways to a substantial extent.

1. Maru

The “Maru” technique did not employ steel of differing hardness like the others. Rather, it employed tamahagane (hard cutting steel) alone. This technique was employed for tanto and for what was called a ko-wakizashi, or “small wakizashi,” a midget version of the usual sidearm.

The Maru technique is not exactly what modern sellers of replicas will call “monosteel.” Maru implies that all the usual layering and differential hardening is still done, making the blade more flexible with a hard edge and springier spine. Swords that do not have even these advances used tend to be severely lacking as weapons, or even as means of practicing cutting for personal enjoyment and coolness factor.

The reader may ask at this point: why was Maru used for small blades? Was it because the Japanese were being cheap? Now, certainly, Maru was the least expensive technique. There is, however, a better reason: because it was not necessary.

A full length Japanese sword functions like a lever. For the same force, the tip travels further. However, when that tip hits something, the force against the hand, and the stress on the blade, are magnified. If a blade is properly cutting, this feedback is minimal. If a blade encounters serious resistance, the feedback will be quite significant; without the softer core, a normal sword may well break instantly.

Maru

A very short sword, or a long knife, has either very little or no magnification of such force whatsoever. The potential slashing power is far lower; however, the vulnerability from breaking is vastly reduced. So, the small blades simply don’t need that kind of elaborate help.

Furthermore, a tanto is primarily a stabbing weapon of last resort. You might be able to take down one opponent with it. You would be unlikely to take down five, especially with one dying attacker all over you. If it does one job right – whether taking down one opponent, or for samurai, to commit suicide to avoid the non-trivial humiliations inflicted to captives in old times – it has done its duty. If it did break, it had already done all that was expected.

Copyright Touken Komachi. Used with permission.

2. Kobuse

The Kobuse method is the second simplest, employing a soft core of shingane with a hard shell of tamahagane for the edge and the sides of the blade. Notably, it did not cover the back.

In a swordfight, blocking with the back of the blade would lead to highly visible gashes, though the sword would be unlikely to actually break (since you wouldn’t go far before a cutting edge hits the hard steel on the sides).

On the other hand, blocking with the sides of the blade with tamahagane meant that a weak impact wouldn’t even scratch, but a more powerful impact, even if it wouldn’t break the blade through bending, could shatter the more brittle tamahagane and lead directly to breaking.

The Kobuse method was, in essence, a cheap shortcut taken for the mass-production of blades in times of mass military conflict. Given that swords themselves were not ubiquitous among samurai until the Warring States Period had subsided, mass production was a relative thing.

A real Kobuse sword made with layering and differential hardening was a perfectly effective battlefield weapon. It wasn’t likely to survive actual use without permanent battle scars; nor was it as resistant to lateral breakage. Nonetheless, it did its job. By sheer force of numbers, Kobuse swords did most of the work in establishing the sword as a battlefield weapon rather than a showpiece.

Kobuse

3. Honsanmai

Having seen the shortcomings of the Kobuse method, we can truly appreciate the design behind the Honsanmai method. This type of sword uses a third grade of steel: kawagane, or “side steel.” This is a medium hardness steel composed of tamahagane and pieces of softer and harder iron, all mixed in and hammered and layered to provide a mix of flexibility and resilience with greater durability than shingane.

The Honsanmai method uses this kawagane to protect the sides of the blade. This has two distinct advantages.

First, the Honsanmai blade is far, far less likely to break from a sideways impact than Kobuse swords. (It goes without saying that anyone cheap enough to create a full length Maru sword is begging for broken blades.) The extra “give” of the kawagane allows the sword to distribute the impact better, greatly reducing the brittleness.

Second, while Honsanmai blades would likely be scratched by tamahagane edges when struck on the side, the relative hardness of the kawagane would make these scratches very shallow. Once a samurai returns from a battle alive, or, at least, his sword is returned to his family, the sword would undergo grinding and re-polishing to remove the shallow scratches without running the risk of the blade being ground down to the soft core, making the weapon practically useless. This method made the weapon more durable against wear and tear.

Honsanmai

4. Shihozume

The Shihozume method was simply a Honmansai method sword that used kawagane to protect the back/ spine of the sword as well. As mentioned just above, this did add to the labor, complexity, and expense behind the sword, but not to the point of being beyond the reach of smiths who had mastered the Honmansai method. One imagines they simply charged more for the extra work.

This further enhanced the sword’s ability to survive battle in a state where it could quickly be restored to its full beauty.

Shihozume

5. Makuri

The Makuri method takes the basic ideas of the Kobuse method and the Shihozume method and presses them together. Makuri swords use a shingane core with tamahagane around the entire exterior, including the back and spine.

While being considerably less expensive than the Shihozume method, this does retain the fear of potential breaking. However, the back protection is pressing against a rectangular shingane core. This allows the shingane to function as a solid spring, if you will. An impact against it will tend to be absorbed fully by the springiness of the core, resulting in not only a lack of scratching, but very low odds of breaking, if the wielder is parrying with the back of the blade.

This result, filtering back to the smiths as such blades were used on the battlefield, must have inspired very interesting conversations.

Makuri

6. Wahira Tetsu

The Wahira Tetsu method uses tamahagane for the edge of the blade only, and uses shingane for everything else. This makes the sword still able to cut as well as any other, but makes the rest of the sword incredibly flexible and resistant to breaking. The edge’s tamahagane and the layering and differential hardening of the shingane would serve to prevent the sword from bending so much that it would threaten to shatter the hard steel.

While extremely resistant to breakage, this sword type was also extremely vulnerable to scratches and gashes along its sides. Thus, while simple to construct and very efficient with its use of tamahagane, the wielder had to be resigned to the blade looking quite banged up after any amount of parrying. This is a choice that a practical warrior may well have made, fearing that a Kobuse sword would break, but not having the time or money for a better sword.

Wahira Tetsu

7. Orikaeshi Sanmai

This is a spin-off of the Honsanmai design. While the end result might seem similar, the left and right sides of the sword are actually separate until being forge-welded back together. We may consider this to be a smith’s idea of making some aspect more convenient. The end result is still a shingane core, kawagane sides, and tamahagane for the edge – and nothing protecting the shingane in back.

Orikaeshi Sanmai

8. Gomai

The Gomai method is a rare bird: it does not have a shingane core. Rather, it employs a thin layer of kawagane around a tamahagane core, sandwiched between the core and tamahagane on the edge and sides.

The purpose must have been to make the entire blade extremely scratch-resistant while providing a touch of resilience and flexibility that the Maru method never could have. One wonders how it worked in real life. At any rate, Gomai is a rare variant.

Gomai

9. Soshu Kitae

This method used a shingane core with tamahagane for the edge, and more tamahagane protecting the sides and the rear. However, there was one additional twist.

This method used a layer of kawagane sandwiched under the tamahagane on the sides.

What was the purpose of this, you may be asking? It’s quite simple, in a sense.

By using medium hardness steel sandwiched under the hard steel protecting the sides, the sides were on the one hand, extremely scratch-resistant, and on the other hand, had a “cushion” beneath the surface to distribute the impact force and prevent any hint of the brittle tamahagane losing its physical integrity.

Anything that the kawagane didn’t disperse on its own, the shingane would cover. Because the kawagane was harder than the shingane, the force would be distributed to the shingane along the entire length of the kawagane, rather than transferred to a tiny section like tamahagane would with the Kobuse method.

Also, like the Makuri method, the tamahagane in back wasn’t a problem; even without kawagane as a cushion, the fact it was transferring force to the shingane lengthwise, not across its side, allowed the shingane to function as a spring. This fully absorbed

Soshu Kitae

the impact force, while the tamahagane emerged with, at worst, barely a scratch.

Thus, the Soshu Kitae method was the ultimate Japanese sword construction technique, producing a blade of exceptional quality as a weapon with incredible resistance to scratching and breaking. The justifiably proud swordsmiths did not skimp on making these weapons into true pieces of art, either. Thus, these were durable masterpieces; so long as they were not abused, they would survive even fierce battles with a few, easily removed scratches, and still be as beautiful and deadly as ever.

This was the method used by Masamune, the legendary figure at the pinnacle of Japanese sword making. He is revered for good reason.

Truly, blades such as these were beautiful on the outside and the inside.

A portrait of Masamune.

Addendum: A Note About Muramasa

Some familiar with the swordsmiths of legend may be wondering: okay, why was Muramasa a great swordsmith, but has been assigned such a bad reputation? Where “Masamune” swords are viewed as the sort of weapons a Luke Skywalker would wield, “Muramasa” swords are associated with Darth Vader type villains. Why is this?

Really, it’s a matter of historical accident. The family of Tokugawa Ieyasu (who for some strange reason, is listed even in the West with his family name first, given name last) had a particularly star-crossed history with Muramasa swords. He had lost many friends and family to them, and had once been badly cut by one himself. Finally, Ieyasu simply banned his own samurai (that is, under his direct authority) from wearing such blades. Pop culture did the rest.

With the Tokugawa shogunate ruling Japan for over two centuries later, the mere wielding of a Muramasa blade was considered treasonous (a very dangerous thing under a powerful military dictatorship). Plays presented the blades as evil, bloodthirsty, and demonic, often demanding blood before they may be sheathed: if not the blood of an enemy, then the blood (and life) of the wielder. This fit very well with the all too serious and all too real consequences of referring to the blades as anything but evil where the government could see it. Instead, the blades became grist for drama.

In modern times, Masamune and Muramasa swords are staples of video games, with Masamune swords always celebrated as #1, and Muramasa swords always ever so slightly denigrated as #2.

Want To Learn Japanese?

This book demonstrates my love of Japanese culture. I have always had a strong interest in Japan, Japan's history, and Japanese popular culture.

My first contact with the names Muramasa and Masamune were in Final Fantasy video games. These were the formative experiences that drove me to learn Japanese, spending years of effort, first as a learner, later as a translator.

Today, I work as a professional Japanese tutor. After years of learning difficult kanji compound words, I took upon myself the challenge of making early Japanese accessible to beginners and early intermediate students. The world has not seen enough good explanations for early learners. Learners themselves have not received enough help to break down the language barrier and begin mastering this rich, challenging, and deeply enjoyable language.

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