In a previous post I made the observation that modern blades have tended toward the katana/sabre style of curved blade. I suggested that perhaps the katana design is better and that is why more modern military blades moved in that direction. Upon further thought, I might have over simplified the situation.
Curved blades on swords served different purposes. I'll talk about two. Kukri blades are curved to place the balance of the striking edge forward, similar to an axe. A similar balance can be found in some machetes and other 'tool' blades.This kind of curve is also popular in the Philippines. It's similar to the Greek kopis Why? Well sure these swords can cut people, but are they better? Yes. They're better like an axe is better. The balance toward the end of the blade means that they can chop. Think about it. If you live in a heavily jungled area like the Philippines or Nepal you're going to need to chop. You might have seen movies where the adventurers are chopping their way through a jungle with a machete. It's not just cool looking, it's also very practical. Jungles grow like crazy. The environment encourages heavy undergrowth, and to get a group of people through that undergrowth you'll need to clear a path. This curved blade is very useful at chopping. Not just people, but plants.
The second benefit of a curved blade is with cutting. This is not the same as chopping (just go with me here, I love playing with words just to mess with people but I'm not just messing with you now. Seriously chopping and cutting. two different things. Okay? Okay.) When you chop, as with an axe, the force is straight up and down. You are using the weight of the wedge (the axe) to split the target.
Cutting on the other hand is when the blade is pulled across the surface of the target, like with a saw. (but without the saw teeth, or else it would be sawing. Bear with me, I have a point.) For an example, think of cutting a raw steak or chicken. If you simply press your blade down into the meat you'll need to use quite a bit of force, but if you draw your blade across the meat is splits without much resistance.
Drawing your blade across a surface is what a curved blade is really good at. When you cut with a curved sword it keeps the pressure at the point of contact. This kind of curved blade is a cutting and slicing machine. And it's quite effective against unarmored opponents. Cutting against chain mail or armor is mostly useless. Armor is best defeated with crushing blows or thrusts.
So why is any of this important? My earlier statement suggests that the curved katana blade has some clear advantage that made other weapons emulate it (knowingly or not). But that advantage is not found in a unopposed world. The advantage of a blade curved for cutting is that it is great against unarmored enemies. But who would go into battle unarmored? Well, pretty much everyone as soon as guns came around. Guns made traditional armors nearly obsolete, and when designing swords for use against clothing then you don't have to worry about how to penetrate the armor. Thrust weapons (like foils) are designed to thrust between the gaps of armor. Some foil type weapons didn't even have edges, just sharp points for stabbing. But a weapon just for stabbing is a gentleman's game when you could have the whole edge for cutting and a tip for stabbing. (check out the ever popular pirate cutlass)
My point is this: tools are designed to do a job. Weapons are tools. If we all started using square head screws, then the flat head screwdriver would become obsolete. The saber style blade probably became more popular because armor disappeared, not because the curve is better, just that it was better for the job that needed to be done. I hastily drew a conclusion that has some credence but there was more to it. I imagine that there's still more, but I think I'm done for now. Thanks for reading!
