I hope the profusion of KDF posts lately is not boring to people, but I've gotten some positive feedback about these posts, and as I generally receive no feedback on my blog posts, I'm going to take that as a sign that I can continue to ... do whatever it is I do here.
It occurred to me that I haven't spoken much about the training gear we use in KDF, or at Sword Class NYC specifically, since it probably isn't totally obvious to everybody.
There are three general types of weapons any modern KDF practitioner uses (I call them "weapons" following the usage of my sport fencing coach at Stanford, who was very insistent that a foil should be treated like a deadly weapon - "Is weapon!" While not all training aids are "weapons" in the sense of being objects designed to forcibly incapacitate a human being, they present the same moral obligations and responsibilities as such objects, so I think this is an appropriate term). These don't have to be acquired at the same time (I personally only own one of the three), but a complete training regimen will eventually incorporate all three. At Sword Class NYC we only use the first two, although I know there are discussions underway for when and how to add test cutting to our training regimen.
The first type of weapon we use is called a waster. This is a practice sword (or sword simulator, if you prefer) made of a material other than steel. A waster has or should have a variety of desirable qualities. The first is that it is cheap - roughly 25% the price of a good steel training sword (more on which below). In addition to being cheaper to acquire, a waster is easier to maintain - steel needs to be oiled after use or it will rust, for instance. It should have the same general anatomy as a sharp sword, allowing the practitioner to use it as a stand-in for the real thing. You cannot practice proper placement of your crossguard with a training weapon that doesn't have a crossguard, for instance. No training weapon will ever have the exact same mass distribution (i.e., balance and handling characteristics) as a live blade (the only way to recreate the mass distribution of a steel bar with razor-sharp edges, after all, is to be a steel bar with razor-sharp edges), but it should try to come close.
Wasters are useful in everything but test cutting, but I think they are most useful in sparring. Hitting another person with a steel bar - even a blunt steel bar - poses greater potential for injury than hitting another person than hitting another person with a lighter object that has wider edges. People can and do spar with steel, but wasters allow sparring closer to full speed with less protective gear for a given risk of injury. This is important, since the only way to know if you can apply techniques with the speed and spontaneity a real fight would require is to try them at full speed in an unstructured sparring environment. I was gratified to learn that at Sword Class NYC we spar at full speed on a regular basis (i.e., every week). Full-speed sparring has revealed plenty of gaps in my knowledge and technique that I simply wouldn't have realized in paired drills as quickly, or with the same clarity.
Historically, wasters were constructed of wood. Wood is cheap, sturdy, and has the historical cachet of being what our ancestors actually made their wasters out of. It has the disadvantages of being quite inflexible, which means that not all techniques can be performed at full speed with wooden wasters. Stabbing somebody at full speed with a wooden waster is more than most protective gear can handle; in fact, as I understand it, Meyer doesn't teach thrusting techniques in his longsword manual precisely because there is no practical way to safely practice full-speed thrusting against a practice partner using a wooden waster. Even cutting techniques can be dangerous (imagine "practice" hitting somebody with a wooden baseball bat as fast as you would if you meant to kill them).
Of course, one certainly could fashion practice gear that can handle the abuse of wooden wasters in full speed sparring. It is not particularly difficult to make armor that will laugh off the best that a sharp sword can do, let alone a sword made of wood. The trouble is that such gear is (i) expensive to acquire, and (ii) can be physically restrictive, which distorts the very techniques one is trying to practice. When I started reading about historical European martial arts in high school, practitioners were still talking about how to make padded foam wasters in their quest for practice weapons that could be used at full speed with an acceptable minimum of safety equipment. The trouble with padding is that it tends to radically distort the mass distribution of the weapon towards the blade. You can't pad the blade without adding mass to it, after all. Today, "synthetic" wasters use plastic blades, which give a reasonable facsimile of proper mass distribution, flex safely when you stab them into a practice partner (think of the way a fencing foil is designed to bend when it hits the target), and can be whacked into a partner with reasonable safety (emphasis on the reasonable - as Tristan has pointed out several times, even synthetic weapons can and have caused serious injuries. High-tech safety gear is no excuse to recklessly endanger your sparring partner, or yourself).
Synthetic wasters are not without their own drawbacks, of course. But to see those drawbacks more clearly, it will be useful to discuss the second major type of practice weapon, which is:
A blunt steel sword (sometimes called a "steel trainer," simply a "blunt" or "steel," or a federschwert - which, at least in its modern HEMA usage, is a neologism, but probably a useful one) is a training weapon made of steel but without a sharp edge. At least some historical blunts may have been live swords earlier in their lives, but modern commercially available steel blunts are purpose-built as training weapons. A steel training sword more closely approximates the mass and mass distribution of a live word (wasters, being made of material less dense than steel by definition, tend to be on the light side - the Pentti+ Type III synthetic waster I use tries to compensate by incorporating stainless steel pieces into the hilt, but it's still on the lighter end of the range of historical longsword weights), but steel's greatest advantage over a waster is the way it handles when it meets another steel blade.
I can't speak as much for wooden blades, but synthetic waster blades have several undesirable characteristics when they hit each other. The first is that their collisions tend to be more elastic than steel, meaning they can actually rebound. The second is that, because they tend not to acquire the tiny divots and nicks that wood or steel can acquire, they tend to slide up and down each other much more than is realistic. The third is that the very flexibility that makes them safer to use in full-speed sparring causes them to flex unrealistically against each other.
This last point is one that bears some explaining. One of the concepts that the German masters harp on is called fühlen. This means "feeling," but I think it is more easily explained as a sword of sword judo. Fühlen is the art of sensing, based on the pressure (or lack thereof) of your opponent's blade on yours, what your opponent is about to do. This is not so that you can oppose his action, but rather so you can exploit it. If he is about to forcefully shove his weapon in one direction (hoping to move your blade out of position, say), fühlen says you should let him - only your sword should no longer be there to be shoved. While his weapon goes shooting off in one direction, yours is busy cutting him down. Just like in empty hand combat, you exploit his momentum to leave him defenseless.
Of course, in order to feel your opponent's momentum through your sword, it needs to have a certain amount of stiffness. If he pushes against your sword and it simply bends out of the way, you don't feel a thing (though you may see his movement). Nothing helps the practitioner to acquire this critical fencing skill like the pressure of steel on steel.
These characteristics make blunt steel particularly desirable for solo and paired drills. This is not to say that they can't be used in sparring, of course. A real steel trainer should be heat-treated such that the blade can flex in the last third or so of its length. Combined with blunt edges and a rounded tip, this means that the weapon can be used in sparring. Protective gear is still necessary to spar with steel, but with the right gear, steel can be used in full-speed sparring, or nearly so. This gear is more expensive than what is required to spar with synthetic blades, and arguably distorts technique by encumbering the practitioner with padding and rigid protection. On the other hand, steel sparring offers a higher-fidelity experience in terms of how the actual weapons feel and handle against each other.
The third type of training aid we use is a sharp steel sword. Sharp steel can be used in solo drills, provided there are no spectators or bystanders who might blunder into the path of the sword, but it is especially valued because only sharp steel can be used for test cutting. As I said in my last post, test cutting is not the apex of KDF practice - one does not graduate from solo drills to paired drills to sparring to test cutting or anything like that - but it is a critical part of complete practice. The only way to know that you can throw a cut (or a thrust, or a slice) that would actually cut something is to ... practice cutting things. If you can reliably win sparring bouts but can't actually cut anything, then you are practicing the techniques of a very oddly shaped stick, not the techniques of the sword.