9. Katana
The katana is easily one of the most recognisable historical weapons. As one of the three blades traditionally carried by the samurai of feudal Japan it is distinctive in style and of incredibly high cultural significance. Wreathed in romance and myth, the katana is considered by many to be representative of the height of martial prowess and the epitome of craftsmanship when it comes to swords. Here's the bone of contention, I don't rate them highly when it comes to swords. The reputation has been overblown by Hollywood and amplified by the mysticism and romance surrounding them. However, the reasons why katanas aren't necessarily the best are exactly the same as the ones that make them an incredibly inventive design. Disagree? You probably still will by the end of this section, but read on anyway. What you want in a good sword is for it to be hard enough to hold a fine edge, flexible enough to absorb and dissipate shock and strong enough to withstand those shocks and maintain its form. A balance between these properties is important, too hard and it won't absorb shock making it brittle, too soft and flexible means it won't hold an edge. Necessity is the mother of invention. What necessitated the design of the katana is one relatively simple problem. Poor quality iron ores, generally coming from iron sand. Poor quality ore means poor quality iron, which means poor quality steel entirely useless for making a sword. What was developed over time was an ingenious combination of techniques that culminated in an effective weapon. The way this was achieved was for three days up to five people would be constantly attending to a tatara, a big clay pot, which when hot enough would have the iron sand and charcoal layered into it. The resulting lump of metal was called kera, which was a conglomerate of steel ranging in carbon contents. These would be carefully separated out and three of the types of steel were used in blade smithing. These were the soft, low-carbon hocho-tetsu (wrought iron), the harder, higher carbon tamahagane and the very high carbon content naba-gane (cast iron). Individually none of these metals would make a usable blade. Hocho-tetsu would bend, naba-gane would snap and the tamahagane would contain impurities and inclusions, as would the other two. To compensate for this the tamahagane and naba-gane would be folded and hammered out repeatedly. This evened out the carbon content, helped eliminate inclusions and the repeated heating process would help burn off some of the impurities. This combination of properties helped create something hard with more ductility. At this point I would like to quickly debunk something of a myth. There's an idea that a blade might be folded thousands of times. Actually it wouldn't be folded much more than about sixteen times. However, what this created was thousands of layers within the steel, because each time you fold it you double the number of layers. So once it is folded a blade can be made from this and you have one of the simplest methods. The blades were typically quite rigid, didn't absorb shock too well and were more brittle, but they were still damn good considering the starting point. The higher quality blades would be laminated. There are numerous different lamination patterns depending on era, expense, craftsmanship and available resources. In its simplest form the hocho-tetsu was used as a soft core and have the harder steels on the outside. This meant the soft core would act as a shock-absorber with the harder steels acting as an edge. In addition to this the shape of a katana also makes it more structurally sound as a curve will dissipate a shock better than a straight edge. Katanas still tended to be quite rigid though, the curve made for a great slashing weapon, even if not quite as good at thrusting and would hold an edge. There it is. I wouldn't suggest that katanas are bad, in fact I particularly like curved swords. I'm merely suggesting that they are the result of an ingenious and incredibly inventive means of compensating for having to work with poor materials, rather than being the progression of and superior form of weapon-smithing. I believe the legend has arisen from the fact that they, and any other bladed weapon made with this method, would have been far superior to one made otherwise, from the same materials.