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Post by 293master293 on Sept 11, 2008 6:31:05 GMT
I explain why I think curved swords usually cut easier than strait swords.
I may be wrong on this, but it is the best explanation I can think of.
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Post by Deleted on Sept 11, 2008 12:53:53 GMT
Ya got some good theory going there.
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Post by Tom K. (ianflaer) on Sept 11, 2008 17:16:05 GMT
this is a sound theory but I want to put it to the test. what I'm going to do next weekend when I'm home (not this weekend as in day after tomorrow but the one after that) is I am going to get out a katana and my CS Broad sword and I am going to hold the edge of each up to a plastic bottle (I'll use several of different size and shape) and I am going to measure and mark on the blade the part of the blade that touches the target with no pressure applied. I will then be able to compare the difference of edge length making initial contact on a straight sword vs. curved. we'll see what that tells us.
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Post by 293master293 on Sept 11, 2008 17:19:34 GMT
Sweet Ian. I know that what I explained isn't the only reason why curved swords cut easier, I just know that this is one of the reasons. It was late last night when I recorded this, and I couldn't think strait so I missed a couple of things.
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Post by Deleted on Sept 12, 2008 3:49:35 GMT
This has actually been debated many times. The results (that I've come across), usually end up being that the katana (representing curved swords) has only a microscopically smaller point of impact than a straight edged long sword. Does it affect things? Well...someone dug up some 'force of impact' tests somewhere on the net (I believe this was on SFI...it's been about 3yrs though so I could be mistaken lol), and the difference was negligible.
HOWEVER!
The katana's force of impact dissipated almost immediately (basically once the cut started). The longsword's force of impact did dissipate...however at a much slower rate than the katana. Measurably slower. They tried different cuts (adding draw etc) and while they did improve the longswords cutting capability, it never came close to comparing to a katana's. JSA strikes naturally incorporate draw. Add to that the shearing action of the curved edge (picture one of those paper cutting tables...notice they rarely, if ever have a straight blade?), and there you have your legendary ability to cut.
Hope this helps!
Cris
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Post by Deleted on Sept 12, 2008 6:11:38 GMT
I've had a look but can't find threads like that on SFI... if you know where to look I'd be greatly interested in that data! To try and check my understanding I'd like to paraphrase... Katana has great penetrating ability (e.g. the beginning of the cut) while the longsword may continue applying force to the target for longer periods (better cutting through the middle of a target?).
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Post by Deleted on Nov 18, 2008 16:44:04 GMT
=/ hmm i think you may be right. more or less, on the right track if nothing elese
im sitting here messing with my fingers now xD and your right , curved finger works better =P
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Post by 293master293 on Nov 18, 2008 21:00:00 GMT
=/ hmm i think you may be right. more or less, on the right track if nothing elese im sitting here messing with my fingers now xD and your right , curved finger works better =P Thanks.
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Post by rammstein on Nov 18, 2008 21:53:13 GMT
...I'm sorry but this is a VERY poor argument.
Using your fingers leads to SO many variables which you can't control that it's almost mind boggling.
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Avery
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Post by Avery on Nov 18, 2008 22:55:11 GMT
IMO, There are alot of reasons a beginner can cut easier with a curved blade. Things like stance, force, lenticular blades, secondary bevels, etc,etc. Having said that, you bring some good points with your theory.
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Post by Deleted on Nov 30, 2008 19:20:30 GMT
Being a southern style kung fu practitioner for 9 years, I can tell you that historically and technically this theory is fact. In my martial art we use our daos (the curved boardswords) as slashing weapons to cut or to sever, while using wu jian ( straight twin edged swords) as a thrusting weapon.
now a straight sword can slash and a curved sword can thrust, but technique and form change when using them outside of their purpose. such as for a straight sword to slash, more body rotation is required because the sword needs to stay in the target longer, so your point of entry with a straight would be much lower down the blade where as a curved sword can start from the mid-upper region and finish out or stay in that area throughout the cut, because the curvature is doing all the work. so with more body rotation and alittle work with the wrists, a straight will slash and cut through a target, it's just the blade has to have an angle at entry and a pulling motion throughout the cut.
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Post by Deleted on Dec 1, 2008 0:53:53 GMT
Fortunately for science, one's experience doesn't build facts. What is being discussed is within the realm of scientific investigation and so claiming experience in a martial art isn't really going to help elucidate what's going on - many people who can 'do' do not always know accurately 'why' they can.
The problem with what Master is trying to say is that not all targets are flat (which, if against a large flat target, his hypothesis would probably work - increased pressure initially due to low blade surface area contact) and that at the scale these phenomena are operating, the contact area along the length of the blade is probably not the deciding factor - edge geometry and other aspects of technique may be.
Now for an anecdote as food for thought: I have been refining my technique with a longsword and slowly slowly my cutting is approaching that of what it is with a katana. If I had learned this technique first it is likely that I would think cutting with curved swords is more difficult.
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Post by Deleted on Dec 1, 2008 3:56:29 GMT
Your absolutely right, not all targets are flat. Infact, most targets (body parts) are curved or round. Swords were created to kill a human, different swords have different applications. With a straight sword if you need to slash, an arm, leg or the neck are the best results because they have they're own curvature which means less friction. Curved blades do this better because theres so little friction on impact, resulted from the geomatry of the blade. I don't know for sure but I think curved blades came into existence to deal with flatter surfaces like the chest and back area. So, theres the science; less friction results in better cutting ability.
And it's interesting to hear your experience with the longsword. Science has it's theories in this subject but never accounts for the x factor which is the wielder. Theres always progression in our techniques the more we practice and learn. What we thought was impossible before refining our techniques is now possible with newly found abilities, which is why in martial arts you can't think in absolutes or you'll never better yourself.
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Post by Deleted on Dec 10, 2008 2:59:29 GMT
I've had a look but can't find threads like that on SFI... if you know where to look I'd be greatly interested in that data! To try and check my understanding I'd like to paraphrase... Katana has great penetrating ability (e.g. the beginning of the cut) while the longsword may continue applying force to the target for longer periods (better cutting through the middle of a target?). Sorry, I seemed to somehow have not received notification on this thread. I just looked on SFI and couldn't find it either =/. Maybe it got removed for some reason...or I'm just not seaching the right terms anymore. It was in the performance swords forum if I recall. As to your summary, it's actually sort of backwards. Picture hitting an object with a baseball bat. The FULL force of the impact is applied to the target (remember, the force of impact comes from BOTH the object swinging, and the object being hit!). The katana only has MINIMALLY, and I mean, almost immeasurably better penetration than a straight edge sword. Basically so little as to be disregarded. But here's the thing...once the initial cut is made, the katana shears through the cutting medium. The blade is naturally drawn (there is no 'chopping' cut I'm aware of in JSA) by the swordsman's body from the initial point of contact, back towards the swordsman. This creates a HUGELY efficient cut. The blade is slicing, the resistance to the cut is very minimal. The actual force being transferred from the blade to the target is small. See what I mean? The initial force transferred (impact) was similar to a straight bladed sword, but the force dissipates (read: remains as energy to propel the blade) as the cut proceeds, due to the shape of the blade, and the 'draw' of the strike. In the testing, the longswords efficiency improved with draw cutting, but it never reached the katana's efficiency (efficiency = the amount of energy RETAINED by the blade...i.e not imparted to the target). There was actually a large spread between them. I think this is simply a matter of the curvature of the blade facilitating a slice, rather than a chop. Make more sense now? Cris
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Post by Deleted on Dec 10, 2008 3:58:19 GMT
Hi Cris, thanks for taking the time to explain your ideas! It is a pity that we can't find this data as it sounds very interesting.
That slow-mo thread featuring James Williams shows something interesting about his particular JSA and there is actually very little (if any) draw in the cut while it is going through the target - the slow motion shows chopping style cuts and yet they are very effective.
I think that the actual edge geometry (e.g. that katana are usually sharper/more acute and are quite rigid) plays a much bigger role than is usually noted... people seem to focus on the small amount of curvature - maybe because it's the most obvious visual difference?
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Post by genocideseth on Dec 30, 2008 10:13:44 GMT
This makes quite a bit sense. I never actually thought of it like this, I usually came up with different conclusions.
Another note: Did anyone else try mimic his hand movements while watching the video? ;D
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Post by Deleted on Dec 30, 2008 10:22:54 GMT
This makes quite a bit sense. I never actually thought of it like this, I usually came up with different conclusions. Another note: Did anyone else try mimic his hand movements while watching the video? ;D Which part made sense lol? There were a few different points of view =). Cris
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Post by Deleted on Jan 2, 2009 15:44:49 GMT
I thought I had commented on this??? I guess I meant to and forgot.
You should be able to prove or disprove theory with real testing. You can use a variety of material; foam, cardboard, fabric and leather. Stretch the material taunt between two clamps and halfsword down at the exact same angle with a straight sword and then a curved sword. You can stand on a scale and have someone watch to see how much the weight decreases as you press down until the point where you push through. The results may surprise you because at the same angle while the curved sword will press with the curved part of the blade, the straight sword will press with almost the tip.
Things changed considerable when you strike a human body because the surface shape is not uniform. Depending on where you strike, you might get more or less edge contact with either blade.
What is certain is that a curved sword make for better slicing motions while a straight sword makes for better hacking/cut motions. This is easy to prove by putting a peace of thick leather up on a plywood. This is an experiment I have done. First take the curved sword and hack, then slice. The do the same thing with the straight sword, first hack, then slice. You will see the curved sword is most effective when slicing and the straight works best when hacking.
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