Katana question

[thardey]

Hey all -- I'm doing some research into how a pommel, or lack of affects sword handling.

Soooo, I have a favor to ask of anyone who has a "functional" katana. The more traditional, the better, but I also need a variety of swords tested, to look for a pattern.

I'm trying to find the "Pivot Point" of various swords. The way you find it is this: tie a string around the handle where you would normally grip the sword. (If you mostly grip using your middle finger, tie it there.) If you don't want to bother with a string, you can loosely hold it with your fingers, just be careful not to put any lateral influence on the sword.

Then, holding only the string, "waggle" your sword in a small circle. There will be a place somewhere along the blade that doesn't move. The rest of the sword will sort of "pivot" around it. This is the "Pivot Point". If some people will test their sword for me, and post the location of their pivot point measured from the tip, along with the overall blade length, I would really appreciate it. I would do it myself, but I've never even seen a true katana in my life, much less have access to one for testing.

If you want to include other types of swords, please feel free, just let me know what kind of a sword it is. (Chinese Broadsword, and Wakizashi would be interesting to test, as well.)

All I've been able to test so far (other than rapiers or longswords) is a shinai, and its pivot point is about 12 inches from the tip, or 1/3 of the blade.

My theory is this: For a well balanced blade that doesn't use a pommel (the counterweight is in the tang) I'm predicting that the Pivot point will consistently be 1/3 the distance from the tip to the point where you are holding the sword. If it does use a pommel, then the Pivot point will vary.

 

[Flying Crane]

I don't have any experience with katana, but I do have experience with Chinese straight sword, or jian, and broadsword, or dao.

I actually rebuild my own swords, because most of the stuff readily available on the market is junk. You can find some pictures of a few of my pieces here in the picture gallery. If I can find a blade that is decent quality, I will take it, strip the hilt away, and completely rebuild it in a manner that is consistent with the use of a jian or dao, even if the style itself is not exactly historically accurate. I don't worry so much about style, as I do functionability.

I carve grips out of hardwood, and cast solid guards and pommels out of either a silver alloy, or bronze.

The weight of the guard and pommel is very important, as it will greatly affect the balance point and thus, how the sword feels and handles in your hand. I have never done the experiment that you have suggested, instead I just lay the blade across one finger to balance the weapon and find it's balance point. This may or may not be equivalent or similar to your "pivot point".

Where a sword balances varies from weapon to weapon, and its "proper" balance point is largely subject to personal desire, in my opinion. My sifu perfers the balance point to be right at the top of the guard, while I prefer it to be about 3-5 inches down the blade, depending on the length of the blade and the overall weight of the weapon.

I find that only the superlight modern-wushu type weapons can have a balance right at the guard. These weapons are merely props for performance and competition, and are not real weapons at all. The blades are made of a very light and flexible metal, and it is easy to weight them in the pommel to make a balance point at the guard.

My own weapons are much heavier, and are essentially "combat" steel, flexible but much stiffer, thicker, and actually useful in a fight. Also much heavier, ranging from about 2 1/2 to 4 pounds overall.

It becomes impossible to pull the balance point back too far, as the weight needed in the pommel becomes much greater, for each increment of distance you pull back the balance point. For example, (these numbers are purely hypothetical) let's say the unhilted blade balances at about 12 inches down the blade. If I add 6 ounces of weight in the pommel, the balance point pulls back to 6 inches. Thats an average of two inches per ounce. But as it gets closer to the hilt, it takes more weight to get the same repositioning of the balance point. Perhaps the next inch takes three ounces, and the next inch takes another 4 ounces, etc. In order to get the balance point all the way back to the hilt, the pommel becomes something like a bowling ball, and the sword itself becomes unuseable. So I have to find a reasonable trade-off between where the balance point is, and how much weight to add to the pommel. I have also read that if a pommel is too heavy, it can set up a series of vibrations in the blade when struck, that can actually break the blade. So here is another reason to not make it too big. Probably something around 5-7 ounces is ideal, altho I have some heavier blades that were my early experiments, where I have pommels over 10 or 12 ounces. The blades on these are around 34 or 36 inches, and are quite thick and heavy.

Also, in the Chinese jian, the guard tends to be somewhat "blocky" in shape, and this adds weight and affects the balance point as well. So it all fits together as a big picture, and you can't focus exclusively on one while ignoring the other.

I personally don't like the balance to be right at the guard. The sword feels "dead" in my hand. I have to give an effort to get the sword to move, and I don't feel it has any mass behind a cut to make it good. However, a sword balanced like this has a feeling that is just "floats" in your hand, and some people definitely like this.

If the balance point is a few inches down from the guard, then the weight of the blade itself gives it momentum, and I feel that my job is to guide the sword, rather than swing it. This is a "living" blade, in my opinion, a blade that is always potentially in motion. Newton's law: what is in motion tends to stay in motion, what is at rest tends to remain at rest. To me, this describes a "living" vs. a "dead" blade, as I have described.

Another factor is in the length of the grip. A weapon with a single-handed grip, say about 4 inches long, will have a balance point further forward, all other things being equal. If that same weapon had a longer grip, say more like a hand-and-a-half, or ever two-handed, about 7-9 inches long, that balance point will be closer to the guard, even if the pommel and guard weigh the same and the length and weight of the blade is the same.

My own weapons have blades from about 28 inches to about 36 inches, and grips that vary from about 4 inches to 9 inches. So it's hard to give a single answer to your question, but I hope this gives you some perspective and something worthwhile to think about and help your project.

 

[thardey]

FC, thanks for your reply. But it really is the Pivot point I'm after. I build swords from "scratch" (that is, blades are from leaf springs, forged in my backyard, guards and hilts manufactured from bar stock, handles turned on a lathe, etc), so I'm familiar with balance and percussion points, etc. I've only built European blades, though.

Although, it is very enlightening to learn about the Chinese blades, it will be very, very, very, helpful for me now to find the pivot point on your blade, especially now that you've been so kind as to include all of the other data.

The weight of the guard and pommel is very important, as it will greatly affect the balance point and thus, how the sword feels and handles in your hand. I have never done the experiment that you have suggested, instead I just lay the blade across one finger to balance the weapon and find it's balance point. This may or may not be equivalent or similar to your "pivot point".

No, the pivot point is at the opposite end of the blade from the balance point. It's the combination of pommel, hilt,tang, and blade taper that affects both the balance, and the pivot point. The balance point is easy, it's just a question of arm, weight, and fulcrum. The pivot point is one of those things that separates a swordsmith from a blacksmith, it's easy to find, but hard to control, without screwing up the other favorable characteristics of a sword.

It's the pivot point that changes the "use" of a particular sword design. For instance, my rapier is balanced about the same place as your swords, (3 inches from the guard), but I can guarantee that it handles differently. It's pivot point is only 2 inches from the tip. In fact, it seems that almost all combat-swords are balanced in the same place, but not all pivot in the same way.

I have also read that if a pommel is too heavy, it can set up a series of vibrations in the blade when struck, that can actually break the blade. So here is another reason to not make it too big.

It's usually the tang that is broken by an over-weighted pommel. When the blade suddenly stops, the tang flexes until the pommel finally stops. This can eventually snap the tang.

 

[Flying Crane]

fair enough. I'll pull out a few of my pieces and give your experiment a try.

 

[Flying Crane]

OK, I think I need some help on the technique. Could you describe in a bit more detail what exactly I'm trying to do?

 

[Sukerkin]

When it comes to a technical discussion of the nature of sword construction, it might be worth a trip over to SFI as they have a number of active smiths there.

There are quite a few threads on points of balance, harmonic nodes, steel constituents, methods of forging et al. A quick use of the search function should garner you enough reading material to keep you busy for quite some time . It's all very interesting stuff and when I first looking into it a few years ago I was amazed at just what a complex beast a sword is .

 

[Yari]

Youre request isn't that easy. It's easy to do, but to draw a conclusion, there are many otherthings you'll have to take into consideration.

1) The steel type( different softness, hardness, smithing (hardning of the sword)
2) The katana type(variation in length, wieght, tang and so on)
3) The difference of holding the sword compared to "hanging" it


But I agree with Sukerkin, try and talk to some real swordsmiths.

/Yari

 

[Charles Mahan]

Katana are two handed weapons. While used one handed occasionally, that is not the usual method. Where precisely would you propose that the string be tied? Left hand or right hand?

I suspect the sori would greatly affect this test as well.

 

[thardey]

I've been to SFI, and the concept that I am trying to research is a new theory, put forth by this guy, (warning: long and technical page) and it hasn't caught on at SFI yet, at least, not in a "quantifiable" way.

More detail for FC: (I'll copy from the the source page)

There’s another handy way to find these points on a staff, which doesn’t involve impact, and which is very useful if you start doing any modifications to the staff, such as tapering the ends or adding a spear point. Just take the staff in hand and hold it vertically by very lightly gripping it with your thumb and finger. Then shift your hand around and watch the staff pivot around a point somewhere near the top end. Gravity will mess with the test a bit, which limits its accuracy, as will any actual torque you apply with your hand. Don’t wave the staff around like a wand, act like your trying to do a crazy staff-balancing trick at a party.

[SIZE=-1]Figure 5 - The waggle test for a staff[/SIZE]​

The key to these tests is that you don't apply any torque. If you only apply side forces, which act like the forces from an impact, the staff will rotate around its natural pivot point, relative to your hand's location. A slightly better form of the staff test is to balance the end of the staff on your open palm, which certainly can't apply any torque to the shaft. This test also works well for swords, but you lay the cross across you thumb and forefinger, which also virtually guarantees that you're not adding any torque, since you're not actually gripping anything.

​

Swords and Pendulums

Another way to guarantee that you don’t apply any torque while performing a “waggle’ test is to apply the sideward forces with a string, since strings don’t normally transmit any torque. All a string can do is pull, so if you use a string to move the hilt, you can’t be applying wrist torque. But knowing this brings up another interesting observation. Since the pivot point doesn’t move when the forces are applied at the impact point, it isn’t feeling any tangential forces. If there were an unbalanced force on the pivot, it would accelerate, which would change its velocity, and that doesn’t happen. Similarly, when you perform a “waggle” test, the reason the test works is that your hand can’t move the pivot point without using wrist torque. An impact point and its corresponding pivot point can’t apply torque to each other. Since the impact point and pivot point can’t apply torque to each other, the two points behave as if a string connected them. If the two points were in fact just connected by a string, the observed effect would be the same, pushing sideways on one point wouldn’t affect the velocity of the other point.

(Let's see if the illustration picture comes through)

I've bolded the parts that actually apply to the test. I've also found that it's impossible to do the string test with the point up, but it works well if you let the tip hang.

Katana are two handed weapons. While used one handed occasionally, that is not the usual method. Where precisely would you propose that the string be tied? Left hand or right hand?

I suspect the sori would greatly affect this test as well.

Since he is testing two-handed longswords, he is using the cross as the reference point, which is the furthest forward point that you would hold the sword. But since you don't have the option to wrap your finger around a tsuba, I propose testing it from 1.5 inches from the tsuba, on the handle. (about where your middle finger on your right hand will lie.) If you test it from the left hand, you will get a radically different pivot point.

Youre request isn't that easy. It's easy to do, but to draw a conclusion, there are many otherthings you'll have to take into consideration.

1) The steel type( different softness, hardness, smithing (hardning of the sword)
2) The katana type(variation in length, wieght, tang and so on)
3) The difference of holding the sword compared to "hanging" it


But I agree with Sukerkin, try and talk to some real swordsmiths.

You're right, this is difficult. I'm trying to quantify something that has previously only been referred to as "sword magic". But if I can start finding a pattern on different styles of swords, then I can start interpreting those patterns.

The steel type won't change this particular test, since I'm not striking anything, we're just talking about weight distribution. You can do this test on wood, aluminum, or steel swords, and still get a pattern, if they are made properly.

The katana length will make a difference, which is why I need the overall length to properly interpret the test, but that's easy to include. However, the weight of overall sword won't matter, as long as it is properly balances. The weight of individual pieces will be interesting to note down the line, but aren't necessary for this portion of the research.

Again, all I need at this point is just some measurements of where the pivot point is, the overall length of the sword (or the blade, just specify which), and what kind of sword it is.

I'm hoping that among the "real" katanas, there will be a pattern. For instance, the guy that started this theory found that among all the museum European swords that he tested, the pivot point was always about 1-2 inches from the tip, regardless of the other details, which varied widely. His theory is that since the sword could be balanced without a pommel (as in a katana), that the pommel is not there for balance, but to control the pivot point. I think there is more to it than that, (tang, furniture, taper, etc. all affect the pivot point) but I need to know more about "un-pommeled" swords, and their pivot point before I can take the next step.

Flying Crane's swords really got my attention, though, because here we have swords that are used in a different culture that the European swords, but have pommels. Did the Chinese use the pommel in the same way that the Europeans did? Or do they use in only for counter-balance? I need to see the results of that test to find out.

I'll keep you guys posted as I figure out more. Thanks for your help!

 

[Flying Crane]

More detail for FC: (I'll copy from the the source page)

cool, this makes sense. I was dangling it point down and twirling it, and it seemed like it was pivoting around the balance point. I'll try it point-up and see how it works.

Flying Crane's swords really got my attention, though, because here we have swords that are used in a different culture that the European swords, but have pommels. Did the Chinese use the pommel in the same way that the Europeans did? Or do they use in only for counter-balance? I need to see the results of that test to find out.

I'll keep you guys posted as I figure out more. Thanks for your help!

In what I know of Chinese swordsmanship, which is mostly in the context of Tai Chi Chuan and some limited Shaolin based material, the pommel is definitely used as part of the weapon. We often grip the sword in a reverse grip with the blade running back along the forearm and the pommel facing forward in a way that can be used like a punch. This is part of the reason our guard is more blocky, and less of a European cross style. The blockier guard gives us something to grip in the reverse position.

We have techniques that definitely use the pommel as a weapon for striking and scraping off grabs and such.

The other thing that Chinese swords typically have is a tassel hanging from the pommel, or from the back of the grip, depending on where and how it is attached. This tassel historically would be weighted with lead or brass and could be used to whip and strike as well, esp. when the sword is in the reverse grip. I have mostly removed the tassels from my own weapons, I just find them sort of awkward to deal with, but they are a legitimate part of the weapon and not just a pretty decoration.

You are definitely looking at the weapon in a more technical level than I have ever done. It's interesting, hope you keep us up to date on what you find, and what you believe the results indicate. It might give me something to think about when I am rebuilding swords, altho since I only make the hilts and not the blades themselves, there might be little I can really do with it. I'd love to learn to make blades someday, so the more of the picture I understand, the better.

 

[thardey]

cool, this makes sense. I was dangling it point down and twirling it, and it seemed like it was pivoting around the balance point. I'll try it point-up and see how it works.

I finally found your swords in the gallery - beautiful! Much prettier than what I make. It looks like you could use the cross guard as the "holding point" for the test, it should work well.

The only way I could imaging getting a pivot point near the balance point was if you were holding it on either the sharp tip of the blade, or on the pommel. But then again, maybe somehow the Chinese designed their swords to pivot around the balance point -- that would be quite a feat!

From looking at the relative size of the handle and pommel, compared to what appears to be a light, quick blade, the pivot point may not be on the blade at all, but at an imaginary point beyond the tip.

In what I know of Chinese swordsmanship, which is mostly in the context of Tai Chi Chuan and some limited Shaolin based material, the pommel is definitely used as part of the weapon. We often grip the sword in a reverse grip with the blade running back along the forearm and the pommel facing forward in a way that can be used like a punch. This is part of the reason our guard is more blocky, and less of a European cross style. The blockier guard gives us something to grip in the reverse position.

We have techniques that definitely use the pommel as a weapon for striking and scraping off grabs and such.

The other thing that Chinese swords typically have is a tassel hanging from the pommel, or from the back of the grip, depending on where and how it is attached. This tassel historically would be weighted with lead or brass and could be used to whip and strike as well, esp. when the sword is in the reverse grip. I have mostly removed the tassels from my own weapons, I just find them sort of awkward to deal with, but they are a legitimate part of the weapon and not just a pretty decoration.

That's very interesting -- even though the physics of a sword limit the way cuts and thrusts are delivered, it's always interesting when a style emphasizes the otherwise "non-traditional" uses of the guards, pommels, and tassels. Does the tassel weight significantly affect the feel of the sword?

You are definitely looking at the weapon in a more technical level than I have ever done. It's interesting, hope you keep us up to date on what you find, and what you believe the results indicate. It might give me something to think about when I am rebuilding swords, altho since I only make the hilts and not the blades themselves, there might be little I can really do with it. I'd love to learn to make blades someday, so the more of the picture I understand, the better.

So far, I believe that the construction of the guard, hilt, and pommel are the tools available for adjusting the various points on a blade. Apparently (so far) I've found a center of percussion, and a pivot point on both sides of the balance point, giving me a total of 5 points to adjust and play with. I believe that cultures either learned how to adjust all of those points to fit their sword theory, or their sword theory developed to properly take advantage of all 5 points.

So far I know that rapiers use the extended pivot point to keep the tip properly aimed at the target, so that it is used as a quick thrusting weapon, and that the "cut and thrust" European swords appear to do the same, which was a surprise.

However, Sabers don't have pommels, but are also balanced about 3-4" from the guard. They consistently pivot about 2/3rds of the way down the blade (1/3 from the tip), making them "want" to cut. That's why I predict the katanas will pivot there, as well.

I have no idea where yours will end up, or if there is a difference between the Jian, and the dao.

I believe that the location of the pivot point will significantly change the way a sword is used best, and if you want a sword for a particular use, adjusting the pivot point (I'm still trying to figure out how) will make the sword feel "alive" when used properly.

 

[Flying Crane]

I finally found your swords in the gallery - beautiful!

Thank you!

The only way I could imaging getting a pivot point near the balance point was if you were holding it on either the sharp tip of the blade, or on the pommel. But then again, maybe somehow the Chinese designed their swords to pivot around the balance point -- that would be quite a feat!

I think I really didn't quite grasp what I was trying to do and what I was looking for, so I may have just been way off. I'll give it a try tonight and see what happens.

It's possible that the mass and bulk in the blockier guard is affecting this in a more pronounced way than a lighter European style cross guard would.

From looking at the relative size of the handle and pommel, compared to what appears to be a light, quick blade, the pivot point may not be on the blade at all, but at an imaginary point beyond the tip.

Most of the examples I have posted in the gallery have fairly heavy blades. Not at all like the superlight Wushu toys. Some of these examples are in the 3 1/2 - 4 pound weight category, for total weight. They might be more useful as heavy trainers, rather than an actual battlefield weapon that might be a bit lighter and more agile.

That's very interesting -- even though the physics of a sword limit the way cuts and thrusts are delivered, it's always interesting when a style emphasizes the otherwise "non-traditional" uses of the guards, pommels, and tassels. Does the tassel weight significantly affect the feel of the sword?

It does, but it's most pronounced with the light wushu toys. Since the weapon itself is light, even the fairly light weight of a tassel can make it feel different. On the heavier pieces it makes less difference, altho I just find they sort of get in the way. I guess I just have not focused on that aspect of the weapon enough to get comfortable with it, and I eventually just took them all off.

Of course I've never seen a tassel that was actually weighted with lead or brass. That could change things quite a bit, I am sure.

So far, I believe that the construction of the guard, hilt, and pommel are the tools available for adjusting the various points on a blade.

I guess I've just never been aware of this point. I'll have to take note of it on the pieces I have already done and how it affects their performance, and keep it in mind for any new ones I do in the future.

However, Sabers don't have pommels, but are also balanced about 3-4" from the guard. They consistently pivot about 2/3rds of the way down the blade (1/3 from the tip), making them "want" to cut. That's why I predict the katanas will pivot there, as well.

I have no idea where yours will end up, or if there is a difference between the Jian, and the dao.

We do have a pommel on our dao (my examples in the gallery show them pretty clearly), but I think our technique is somewhat different from a European saber or early American cavalry saber. The dao is the tiger, it is fast and ferocious and attacks aggressively using mostly cuts and slashes. Some of the cuts and slashes are long movements, done with the whole arm and powered by the entire body. But some of those cuts use a whipping technique thru the wrist. I don't know if European or American saber uses a similar technique, but this might be sort of unique to Chinese.

I believe that the location of the pivot point will significantly change the way a sword is used best, and if you want a sword for a particular use, adjusting the pivot point (I'm still trying to figure out how) will make the sword feel "alive" when used properly.

interesting notion to be aware of. I shall go thru all my pieces and see if I can identify the pivot point, and compare how the sword feels in use. Thanks for the new ideas, things to pay attention to.

 

[Flying Crane]

I tried this out again last night with a few of my pieces. It seems that the point changes, depending on how I am doing it. Sometimes it seems the pivot point is at the tip, other times a few inches down from the tip, other times it could be past the tip. I'm just not getting a lot of consistency in the same weapon. I'm not deliberately trying to manipulate it to make it pivot at different points. But if I waggle it a bit differently, I get a different result each time, and I'm not quite sure which is the proper one. I'll play with it a bit more and see if I can get some consistency, or if one way seems more appropriate.

 

[thardey]

I tried this out again last night with a few of my pieces. It seems that the point changes, depending on how I am doing it. Sometimes it seems the pivot point is at the tip, other times a few inches down from the tip, other times it could be past the tip. I'm just not getting a lot of consistency in the same weapon. I'm not deliberately trying to manipulate it to make it pivot at different points. But if I waggle it a bit differently, I get a different result each time, and I'm not quite sure which is the proper one. I'll play with it a bit more and see if I can get some consistency, or if one way seems more appropriate.

Don't worry about it-- that's exactly what I needed (I don't think the test is any more accurate than that, anyway, but it's enough). That tells me (If I'm correct) - that your weapon is a "tip-oriented" weapon - although that doesn't prohibit it from being a excellent cutting weapon, also.

It also means, that your sword behaves a lot like a European cut-and-thrust sword. I'm guessing it works well for cuts, followed by thrusts, if the the cut is thrown properly.

And last, but most interesting to me personally, that since that you have to decide to have the pivot point at the tip (by default, it usually ends up closer to the middle of the blade), that the Chinese specifically decided to put the pivot point there, the same as the Europeans, half a world away, possibly for the same reasons.

Kewl. Thanks a lot!

Any takers for a Katana?

 

[Flying Crane]

Glad to help!

A jian blade is fairly similar to a European blade in many respects. The hilt design is probably the biggest difference, and that is necessary for some of the techniques we use.

In fact, since getting quality jian blades is problematic, I have begun buying blades made by Angus Trim up in Washington State, and rebuilding hilts that are more appropriate for a Jian. Angus makes European style swords, and has many models with different configurations. I have found some that translate quite well into a jian, with the right hilt. So I'm not surprised to see some similarities with this.