concrete cutting edge:) just kidding!

E

elvenbladesmith07

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Jul 29, 2004
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I was reading a book about Japanese swords and they tell how they were tested by the executioner on up to 5 people at once. my question is how these swords could cut through something as dense as bone multiple times. how sharp and how long the edge will last doesn’t matter that much. the force needed to do it I don’t think can be had with even a "horse killer" katana. Anyone know why they could even take a single person I half? I don’t get how a regular size katana can go through a persons arm, let alone 5 peoples mid sections.
I didn’t mean to sound gruesome but it cant be helped in this subject
 
Hmmm. Thats something I'd rather not test, just leave it as a "theoretically speaking" type things :eek:

Blades can cut bone. I remember a martial arts guy doing some tests with Jerry Hossom's knives and one of them easily severed a leg of lamb without sustaining any damage. I think if you talk to Dan Koster he has some info on the tradition (sometimes ritual ) use of Khukuris. I think he's one the who posted pics of a guy beheading a bull with one swing.

Does the book specifically say that the sword would cut 5 people clean in two (10?) though? I could see a tip cut across the middle being pretty hard on a person but wouldn't slow the sword down too much. :barf:
I kind of wonder if this wasn't some mall ninja doing the research. There is a lot to be said for cutting performance and testing but some folks are a little to eager to get into the super killer, ultra deadly stuff.
 
A cut like that would have been done 'do-dan.' The fellows would have been piled up on top of each other (usually already dead) on a mound of sand, and the blade bound into an iron reinforced handle. These guys were specially trained, it wasn't just some joe-schmoe.

Now, on the single body, cuts were done with the fellow tied up to sort of a hangman's gallow sort of dealy, don't remember the name for it. These guys might have been alive as often as dead. There's a story that's been passed down of a fellow that asked his executioner how he was going to cut him. 'O-kesa (from shoulder to hip)' the executioner told him. "That's a shame," the man said, "If I had known, I would have swallowed a few stones to spoil your sword."

It's easy enough to do, as people are mostly squishy bits, and fresh bone isn't very hard.

Darryl
 
That's not as big a deal as it looks like. Take a look at fresh bone. It isn't nearly as hard as dried. The neck vertebra are fairly easy to cut. The chore is getting through the muscle, tendons and ligaments without, for lack of a better term....Jamming or getting stuck.

One of the members here did some tests on a live goat. :barf:
I've done some chopping on dead Deer. :eek:

The trick is always getting through the meat, not the bone.

I have a cutting dummy (Named Deputy Dandridge, don't ask). I found that 1" PVC pipe pretty well duplicated bone resistance so old Dandridge has replaceable PVC bones. Wrapping them with matting comes close to duplicating the real thing. I don't bother with his head. Mush is easy to cut so why waste time.

This sticking is why the Japanese wet the sword before cutting a friends head off :rolleyes: It acts as a lubricant. No Vaseline jokes please.
 
peter nap said:
That's not as big a deal as it looks like. Take a look at fresh bone. It isn't nearly as hard as dried. The neck vertebra are fairly easy to cut. The chore is getting through the muscle, tendons and ligaments without, for lack of a better term....Jamming or getting stuck.

One of the members here did some tests on a live goat. :barf:
I've done some chopping on dead Deer. :eek:

The trick is always getting through the meat, not the bone.

I have a cutting dummy (Named Deputy Dandridge, don't ask). I found that 1" PVC pipe pretty well duplicated bone resistance so old Dandridge has replaceable PVC bones. Wrapping them with matting comes close to duplicating the real thing. I don't bother with his head. Mush is easy to cut so why waste time.

This sticking is why the Japanese wet the sword before cutting a friends head off :rolleyes: It acts as a lubricant. No Vaseline jokes please.
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Now who would do a Vaseline joke????? Butt I bet you like it with the sand in it. :confused: :confused:
 
IIRC a moist reed mat (Tatami 6'x3' and about 2" thick) were used to simulate a body too. So it could also be a stack of these, again IIRC swords were given a rating on how many they were able to cut through.
 
One thing to consider also is the edge geomitry of the traditional katana, it's a full convex grind, which works wonderfully for slashing/slicing cuts. My own test with hunter and bowie sized blades showes that a full convex works best when cutting all the way through something, there's nothing to hang on, unlike a hollow ground blade.
 
Temper said:
IIRC a moist reed mat (Tatami 6'x3' and about 2" thick) were used to simulate a body too.
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I've seen the iaido practitioners use goza mat (the outer woven reed layer of a tatami mat) soaked overnight, rolled & bound with string ties, then jammed onto a spike base to hold it upright as they slice it with diagonal strokes of their katana. The rolled mat more-or-less represents a standing opponent.
 
Matt Shade said:
Blades can cut bone. I remember a martial arts guy doing some tests with Jerry Hossom's knives and one of them easily severed a leg of lamb without sustaining any damage.
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I think it was Maurice (here on BFC or other forum) who did testing of blades with legs of lamb, but could be wrong. I can't locate just now his rather extensive write-up of blade testing. Angle of stroke was apparently a determining factor in whether the stroke went all the way through the leg or not. I thought I had it archived...not so. :grumpy:
 
Hey Rok, if you are heading out to Japan again drop me a line and I will put you up for a couple of nights. I live in Kawaguchi in Saitama. If you like steel and iron works, youv'e come to the right place. :)
 
MATT, the book was writen by historians, and the part where it talks about these test was the edo period, so the sword was most likely a 27-29" blade with a dimond like cross section, and the flat bevel, slightly convex, covered 2/3 of the blade(edge to back <>)the handle is estimated at 11" long so it had some power behind it.
ive tested on wet cardboard wraped around a stick, but never with a katana. just a broadsword.
 
Animal beheading has been (and still is) an annual tradition in Nepal. Yes, it is performed with a khukuri and is required to be done in one stroke or bad luck for the gurkha regiment for one year. This is done using a bull.

Sometimes special (non annual) ceremonies are performed using a goat.

pic = http://www.bladeforums.com/forums/attachment.php?attachmentid=13319




To answer your question, elven - there are swordmakers that test their swords by cutting multiple tatami mats. When they're wet (soaked overnight), they're said to resemble flesh.

When you see one of these events and analyze the swing, you find that what looks like a "push cut" is actually a very long and slow "slice cut" or "draw cut". That is, the cut begins in the bottom 1/3 of the blade and ends at the top 1/3.

So, let's say our tatami mats have "bones" in them....the first one would hit in a spot lower than the second one, and so on. You're not hitting the blade in the same place each time. That could be a partial answer to your question.

The blade would have to be thin, hardened, but slightly flexible for maximum effect.


I'm sure you could find all this info (and more) with a search on swordforums.

They seem to be especially excited about this kind of thing over there. :p :footinmou
 
I have been told that a lot of the mutiple bodies type of cuts also used longer handles than would normally be fitted to the blade just to get the right arc and leverage. No really a cheat since it still needed a whole lotta skill to make the cut :)
 
Years ago I read an orthopedic journal article that tested bone directly from slaughterhouses .Typical bone studies previously had always used old dried bone . The fresh tested bone was much more resilient , not nearly as hard or brittle.....Since butchers have for years been cutting bone with cleavers , what's the big deal ? It's just a matter of picking the right edge configuration ,hardness and blade weight.
 
The only thing I've been cutting lately is the cheez :eek: :D :D Seriously I cut the front legs of a deer off with my 7 1/2" 5160 knife this fall. One whack per leg. That 1/4" thick x 1 3/4" wide convex grind blade did it quick.
Scott
 
mete said:
Typical bone studies previously had always used old dried bone . The fresh tested bone was much more resilient , not nearly as hard or brittle.....Since butchers have for years been cutting bone with cleavers , what's the big deal?
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That's a good succinct answer to Elvenbladesmith's initial question "how these swords could cut through something as dense as bone multiple times" by pointing out that living/fresh bone isn't all that dense or rigid.

I guess the big deal of Mario's cutting tests would be that butchers typically chop through bones that are laid on a chopping block or other cutting surface (i.e. braced against moving away from the edge) while the leg o' lamb cutting is done slicing through free-hanging meat that can deflect and move under the force of the blade.

Also, meatcutters cut the flesh down to the bone with a knife, then chop the bone with a cleaver. Mario's scenario calls for the knife blade to sever its way through the flesh and the bone at a single stroke, thus actually "slicing" its way through the bone structure. So the blade geometry will have to be thin yet rigid & tough enough to simultaneously cleanly slice materials of differing properties (soft & clingly meat/fat and somewhat brittle bone).

Just a quick $0.02 from an former meatcutter. :)
 
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