I keep hearing that straight blades don't cut as well as curved ones, but Viking and early Medieval Euro swords were pretty much all straight, and were designed for cutting. I've never seen a Sabre or Katana cut anything that a suitable straight-bladed sword wouldn't cut.
I must share my disturbed opinion...and I must relate it to cars. Big tires have a big footprint, small tires...small footprint. Concerning a direct 90 degree blow, a curved blade will show more psi on the blow, due to a smaller footprint. If you add a dragging or slicing motion to the blow...then I am in the deep end.
Thinking a bit more. I was going to state that on a 90 degree cut, the curved trailing edges would generate a natural slicing action. Then I started thinking about the length of the hitting edge, say on a wrist. The radius of the curve would be so great in average instances, that it might not even factor?
I suppose the PSI explanation would make sense, although if you're just doing a straight down shearing cut I don't see how slicing would really help at all. Swords usually seem to cut by shearing, rather than slicing like a knife would, which is probably why a good sword does not have to be as sharp as a good knife.
Post by randomnobody on Feb 8, 2010 1:24:01 GMT -5
I think the "built-in draw" explanation is the more likely, myself. The curve transforms natural motions into necessary motions and we have "better" results, whereas somebody picking up a straight blade for the first time is going to whack the target flat-on, with no draw or opportunity to induce a drawing-type movement; the blade will hit the target...and stop.
With a curved blade, the impact force is...I can't think of the right word, dispersed or something, such that the curve of the blade allows it to continue on its path as the target sort of "slides away," in such a way that it basically slices itself on the blade.
Of course, there are likely as many theories on the subject as there are schools of sword.
As far as curved swords "cutting better," I get the feeling that most of the popular explanations are poppycock. If you have similar edge geometry and mass distribution on two blades (one curved, one straight), to somewhat paraphrase the first part of random's comment, it isn't the sword that's cutting better or worse, it's YOU. Your behavior taking advantage of the "built-in draw" use of the curved sword will serve you better than whacking your target flat-on with the straight blade, but there's no reason the exact same edge geometry on the straight one wouldn't cut through it just as easily if it was properly used. The small curve in some blades like a katana is rumored to somewhat match the curvature of the circle our extended arms scribe as they are used in a full range of motion, so perhaps it is more intuitive to cut with an efficient motion using a blade of that shape, but that does not make it any less possible to cut with an efficient motion using a straight blade, nor does it mean the straight sword will cut any worse once the swordsman is trained to use it properly. As far as "presenting a smaller area" to the target with the curved blade, that's a pretty much a load of hooey. Against a cube or something, sure, but most of the targets a sword faces are ROUND, like water bottles, pool noodles, tatami mats, arms, necks, and legs, and the huge surface curve of those targets pretty much negates the difference in the weak curve or absence of curve in the small section of a sword used for cutting as far as how much area is presented.
For me, it seems like it all comes down to the swordsman. A good edge on a good sword will cut well if it is used in the most efficient way possible. Whether or not the person behind the sword is doing his part properly far outweighs the small differences the curve of the blade makes in determining a good cut. But since curved and straight swords require different motions to be used effectively, a person who learns to cut well with one will probably find the other one to not "cut as well." In reality he/she is the one not "cutting as well," not the sword.
Yeah I wouldn't say better, but maybe easier. I find it more difficult to cut with a straight sword but the cuts when performed with correct edge alignment are no different to cuts made with a katana, as in you couldn't tell them apart just by looking.
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There is one thing curved blades cut better than straight: thick cloth layers. Michael Edelson from myarmoury did some katana, bow, sword and poleaxe tests on mail and multiple cloth layer defenses and found out that katana is much better than euro straight sword at cutting layers of cloth. Only thing that got close to katana were tip cuts with spatulate sharp tips on a XIII sword. Btw, good mail proved to be almost undefeatable with sword. Cuts did nothing, only half sword thrust with Albion Talhoffer sometimes broke a ring. Poleaxe cut usually broke a few rings but didn't really cut through but poleaxe thrust through mail was devastating. Complete penetration. Bow also rarely and only from close pierced a ring or two. Katana was a Nihonto I think so he only tested it against a cloth layers.