The katana has been touted as the finest sword ever made, capable of astounding cutting ability, durability and of course beautiful aesthetics. It would be odd if this sword simply sprang into existence from the sketch pad of some smith many moons ago and of course it didn't. The katana as we understand it now is the product of hundreds of years of refinement and responses to changes in what was expected of the sword at the time. Any number of factors would of been greatly influential on the design and manufacture of the sword and I hope to go over these in this article, detailing where the katana started off and where its ended up today.
To begin with I suppose I should also clear up my use of the word 'sword' as it may irritate some people. I talk about the katana and I instinctively use the word 'sword' quite a lot. This isnt actually 100% accurate however so I hope you'll forgive me. Years of calling a long metal object a sword, from my childhood to my teens have made me lazy where this particular terminology is concerned and in fact most japanese swords would be more accurately described as sabres. A sword is a double edged weapon you see, whereas a katana, generally speaking has only a single edge. Regardless of this, I will be using the word 'sword' to describe anything pointy and sharp and I hope you're ok with that.
Enter, the "Chokuto" - pre 987AD
So, the iconic japanese sword had to come from somewhere and most people will agree that it all began with the chokuto. The chokuto came about in a period known as the Jokoto period which was pre 987AD. The swords that were being made at that point were from a technological point of view, the most basic of all japanese swords. The trademark features that we all know and love such as the graceful curvature and the differential hardening techniques had not been formulated at this point and the geometry of the sword showed this. Dont get me wrong, I am not saying that these weapons were not beautiful or well made, simply that the advances that led to the creation of the katana had to start somewhere and this sword was right there at the very beginning.
It was straight and at first glance looked like nothing more than a long sharpened steel bar. Sometimes there was a lot of taper towards the tip and sometimes very little. The usual cross section that you would expect was not present at all in fact it only really came in one of two geometries, either hira-zukuri or kiriha-zukuri neither of which are particularly popular in sword lengths nowadays. We are lucky to know much about these swords at all to be honest being as pretty much all finds are in horrible states of disrepair. Thats what 1000+ years of situational degradation will do to a metal no matter how well forged it is.
A chokuto from the 6th century in surprisingly good condition all things considered
The handle of this sword was very different from the silk wrapped long handled artistry of the tachi and katana as well instead being made exclusively for one handed use, having a smaller grip and a more scimitar look to it. The chokuto became the buzzword for the so called 'ninja sword' amongst martial arts film enthusiasts as well, but this is of course rubbish. As far as I know there was no dedicated ninja sword but even if there were, Im pretty sure they wouldn't of used a sword that would of been already two hundred years old to conduct their business. ;)
The birth of the Tachi
In complete contrast to the straight lines of the chokuto and the relatively crude levels of metallurgical construction that came with it, the tachi leapt into being with a revolutionary design that would set the template for all Japanese swords to come. We are all familiar with the basic shape of this style of sword but this is where it began. The first designs of tachi were in the Shinogi Zukuri style and that means that they were forged with a ridge that divides the cutting surface from the side of the sword.
Diagram to show the extreme curvature at the base of the original tachi design.
The term shinogi zukuri actually refers to that ridge, called the shinogi and the side of the sword which is called the shinogi-ji. The other main feature to this new shinogi zukuri design was the prominent division of the kissaki from the rest of the cutting edge with a geometric change at the tip called the yokote. This was polished further to stand out from the rest of the blade and even now is a much desired trait in modern swords.
Because of the way that these slender swords were now shaped, with the cutting surface leading to the shinogi rather than the blade being flat and full all the way to an abruptly sharpened edge, strength was able to be given to the sword with something called niku. It was a way of shaping the cutting surface so that the maximum amount of metal could be put behind it whilst still allowing it to be sharpened to a lethal edge. They did this by shaping the cutting surface in a convex or 'appleseed' like fashion and this niku is something that is important in all japanese blades from this point onwards.
Niku is the extra metal on the sword that gives it extra strength. Its seen here in the appleseed like convex shape of the blades cross section.
What most people are going to also realise on laying their eyes upon these new gracefully curved swords is that they are now in possession of a hamon, or a pattern on the blade that was a result of the differential hardening techniques that were being employed for the first time.
I wont go into detail on this subject as there are a million different articles available on the heat treatment techniques used by ancient and modern sword smiths already. Maybe I'll touch on it in another article, but the gist of what was being done was that after the basic shape of the sword was forged out, it was covered in clay. a thick layer was painted onto the spine of the blade and a thinner layer on the cutting edge. The blade would then be heated up to critical temperature, (read as, glowing red hot) and then quenched in water. The clay would mean that the spine of the blade would be partially insulated against the water and would cool slower than the edge. The crystalline structures that formed in the metal as a result of this had a few very cool effects.
Firstly, the back of the blade where it had cooled slower, was less brittle and more ductile, lending strength to the sword as a whole. Secondly the cutting surface would harden considerably more, allowing it to take and retain a deadly sharp edge. Finally there was the hamon, the beautiful pattern on the blade of the sword that comes about as a by product of this heat treatment.
Missing something? Ok sure. :) There is actually one more very important effect this had on the blade. Remember the Chokuto was straight? Well the differing rates of contraction of the front and back of the sword metal meant that it was push-pulled tightly into the graceful curvature that we instantly picture when anyone mentions these blades. This curvature is called Sori (also sometimes zori) and is associated with all modern Japanese blades because it is a product of the heat treatment. Now these early tachi had a very distinctive koshi sori, or curvature that begins at the base of the sword and were relatively slender especially when compared to more modern blades. Fumbari was another feature and was always found to some degree or other on tachi. Fumbari is the swelling of the width of the blade near the habaki and some of the advantages of this was that although it added more metal to the blade making it stronger but heavier, it affected the balance of the blade which actually made it easier to wield with one hand. This curvature, fumbari and the fact that the tachi was considerably lighter than its successors, meant that it found itself well suited to combat from horseback where a heavier sword simply would not be practical. The sword was worn with the cutting edge facing down on rope hangers that attached to the belt. This gave it a freedom of movement that allowed it to worn whilst riding.
The ashi hangers seen here were used to attach the saya to the belt of the warrior.
The production of Tachi continued all the way up until the end of the Muromachi period in 1572 but don't be fooled into thinking that the design of tachi stayed the same for all those years. These long slender swords and the smiths that made them paved the way for the katana in the years to come.
To begin with, the tachi started to lose two of the characteristics that were to so heavily define it in later years, becoming wider overall and losing a little of the fumbari. A big change to how the blade would feel in the hand also came about with the altering of the sori, relieving some curvature at the bse of the sword but also introducing it further up as well. This sort of archway or rainbow style curvature is called tori-sori although the modern katana in years to come will exemplify this more.
A tachi from the mid kamakura period. This one has been cut with horimono as well as bohi.
These first big changes started to happen in the Kamakura period along with big political changes and it could be summised that these changes were in no small amount influenced by the appearance of an aristocratic warrior group called the buke. These warriors from important families took it upon themselves to govern and police the provinces and as these groups gained power and confidence, the design of the swords that they would be using was heavily influenced by their own personal taste. Blades of the mid kamakura period tended to look powerful and more heavier set than the first tachi and with few exceptions, this was a trend that would continue into the Nanbokucho period the need for a stout sword being of paramount importance. The famous Nanbokucho war, literally "South-North courts" war arguably stemmed from these political changes and interestingly enough, probably started the demand for yet another sugata.
A more heavily set tachi from the late Kamakura period.
As the Nanbokucho war began in earnest the design of the tachi was altered considerably. This is definitely an example of function over form taking precedence. The overall blade length increased considerably but was made thinner to compensate with less niku than before. Many blades were cut with bo-hi to further reduce the weight and the last of the fumbari seems to have all but vanished from blades of this period. The length of the kissaki was increased proportionately with the length of the sword and was less rounded and more pointed and even the hamon on many swords seemed to have been stretched to match these new dimensions. All these adjustments along with the much less pronounced sori made the sword look even longer than it was already.
diagram showing the basic shape of the Nanbokucho era tachi. A sword made for war.
Throughout this turbulent time, the tachi evolved very quickly and specifically. Continuing this snowballing trend came two other types of sword which I will mention just to hammer in exactly how much this war affected or some may say temporarily derailed the evolution of the tachi. These swords were the seoi-tachi or shouldering sword and the no-dachi or field sword. Both of these swords were huge, sometimes measuring up to 150cm. This really was a weird time, the normal progression of the sword took a small holiday you might say, but after the pseudo-victory of the northern courts in 1392, everything got back on track like nothing happened at all.. at least as far as the design of the tachi was concerned.
A good photo of a heavily set tachi in excellent condition from the Nanbokucho period.
The birth of the katana.
The next big change however took another 80+ years to occur and it's the one that would forever define the japanese sword in popular culture. It was the birth of the katana. This new sword was a lot shorter than the more elegant looking tachi at around 60cm blade length and also with a wider base. Wow only 60cm, Thats almost wakizashi size right? There was no doubt that this sword was a lot more durable than the more delicate looking tachi. The sori or curvature of this shorter blade shifted itself further towards the tip as well (saki sori) as this sword would not be used from horseback, but it also slightly increased the reach of the weapon given its now relatively diminished stature.
Diagram showing the huge difference between the earliest katana and the more modern equivalent.
Unlike the tachi, the blade was worn with the edge facing upwards, not on ashi, but through the belt or obi. This change of wearing habit gives us a method of telling whether or not a sword was made originally as katana or as tachi being as the smiths signature or mei was always placed on the side of the nakago that would be facing outwards when the sword was worn. A common misconception was that the katana replaced the tachi. This is simply not the case in fact the production of tachi continues up to this very day, however the katana was to hit the limelight big time in the years to come.
Quality wise it was a poor start for the katana as it was formulated during a time of conflict in the sengoku period and the demand for them was so strong that they were hammered out as fast as they could be. The tachi of the past were things of beauty because they could be made properly but now there simply wasn't enough time for the smiths to produce such works of art. Even the Nanbokucho civil war did not see demand like this and so there were many poorly made katana during these times with comparatively few decent swords made. All this bloodshed finally came to an end however when Nobunaga decided enough was enough and basically unified Japan beginning the Momoyama period. With the 'distraction' of all this warring and killing out of the way, the design of this new shorter blade underwent the same meticulous scutiny that the tachi did. With the smiths putting all their time and talent into the creation of these newer katana, it is no surprise that they became so beautiful and evolved so quickly in such a short period of time.
For one thing, the length of the blade increased. In fact it jumped forward, right up to around the 75cm mark which is a considerable change from its much stubbier 60cm beginnings. In order to compensate for this extra length, the thickness of the blade increased and so did the width at both the top and bottom of the blade, or the moto haba and saki haba although there was little tapering or fumbari. The curvature of the blade still started part way up, in contrast to the koshi sori of the early tachi but still wasn't text book tori sori and this curvature was extended aesthetically into the kissaki which was often elongated into an o-kissaki form.
A katana in beautiful condition. This one is from the Edo period and features tachi style koshirae making this actually Handachi or half-tachi.
During the early Edo period, a law was passed that restricted the legal length of the blade to approximately 69cm (or its equivalent in shaku, given that they were Japanese). The daisho was also given the once over and it was decided that the short sword should be between 45cm and 54cm long. The daisho of course had been worn prior to this, but now it was officially recognised and regulated. Japan could be like this at times, going so far as to dictate the type of koshirae that could be used or the colours that could be worn, although it was debatable how tightly these regulations were followed. For the time being, all katana that were produced, at least legally, were very close to 69cm in length and had very little sori. This is a very standard length nowadays for katana, give or take a centimetre or two of course.
The late edo period saw an influx of heavily set longer blades that averaged about 75cm in length. They had no noticeable difference in width at the sakihaba as compared to the motohaba so they lost a degree of elegance but they did have a habit of sporting the most beautiful o-kissaki. That and the lack of sori gave these swords an air of strength about them and maybe this is another example of how the intentions of the smiths guided the path to the final product because these swords seemed to be made to give a specific impression. This feeling was one of power as well as beauty.
A high quality reproduction of a modern Japanese katana.
Now all of these different blades in this long progression and evolutionary process, all the history behind them, the techniques, the experimental eras, the blood and sweat of Japanese smiths have been a literal inspiration that has led us to where we are now; the modern day reproduction katana. For forges that actually give a monkeys about the history and the process and understand where this beautiful weapon has come from, the katana has become a carefully refined and stunningly beautiful sword. Smiths in Japan are obviously still forging new swords although it is tightly regulated to prevent the process becoming too commercial and also to prevent mass production deteriorating the quality. You only have to look to the chinese market to see how mass production can hamper the quality of the end product. In contrast, this process from the earliest recognisable steel swords to the modern day authentic Japanese Katana has taken over a thousand years and many generations to complete. I suppose you can see why some people get all irritable when you compare a $50 musashi can cut bamboo one strike 'katana' to one of these historical nihonto.
I mentioned at the beginning of this article that we would be running quickly over the history and evolution of this incredible weapon and thats exactly what I've done. :) If you want to know more, then google is your friend but I hope this has been an enjoyable and informal primer. People think "katana" and a single specific image instantly pops into their heads. But when you talk about this subject, realise that the katana is not a single sword, it's a one thousand and twenty year plus long timeline of situationally driven alterations and improvements to an original design and thats a good thing to remember even if you are just cutting up targets in your garden.