Academic Exercises

by K. J. Parker

  A milder irony lies in the fact that, in 1917, George S Patton, pioneer of modern mechanised warfare, designed a sword for the Army. He was only a young lieutenant at the time, but the weapon he came up with was, by all the arcane criteria of swordsmen and swordsmiths, more or less perfect, the best sword ever issued to an army. It was a light, slim thrusting sword for cavalry use, wonderfully balanced, an ergonomic marvel, and if it was ever drawn in anger, I can find no record of it. The peak of perfection is reached only when the instrument itself is entirely obsolete, and the designer was the father of the impersonal hell of modern mechanised war.

  Patton didn’t just design a sword, he also wrote a user’s manual, setting out a standardised training program for swordsmanship in the US cavalry. The approved method is refreshingly simple; you hold the sword at arm’s length, point it at the enemy and gallop. That’s it. Patton deliberately declined to teach any defensive parries; the cavalry swordsman is basically just a bullet fired at the enemy by his commanding officer, and there’s no need for a bullet to defend itself.

  A sword is a piece of metal, usually flat, usually with a point, an edge, or both. You can cut with it, or you can thrust. If killing is your priority, the thrust is your friend. You’re much more likely to kill with the point than the edge. But if you want to stop the fight as quickly as possible, the edge is probably a better choice. Swords work by inflicting a combination of shock and damage. A stab can damage you fatally but shock you so little that you don’t realise you’ve been hit; you can carry on with the fight, kill the other guy, walk home and only find out you’re dying when you take your coat off and see the blood. By contrast, a severed arm stops most fights, even though it may not kill you, and the pain and shock of a heavy cut will neutralise an opponent even if he’s wearing armour and his skin remains unbroken.

  The thrust is generally a safer manoeuvre to undertake. Thrusts are straight lines. Cuts tend to be arcs. Basic geometry dictates that the thrust takes less time, and needs less elbow room. You can poke a lethal hole in someone with comparatively little effort. To have any useful effect, a cut needs strength behind it, calling for big movements of arm and body. In making these movements, as often as not, the swordsman leaves himself open, presenting an inviting target for the thrust.

  So the point has it, and the edge is nowhere. Maybe, if the other guy’s fighting in his shirt. If he’s wearing armour, the thrust suddenly loses its appeal. All wearable armour has gaps, weak points, joints, into which the skilled swordsman can poke his point, assuming the other guy is kind enough to hold still. But a sword light enough to be usable won’t punch a killing hole through one-sixteenth inch steel plate, the average thickness of medieval armour. Instead it’ll bend, possibly snap like a carrot. A cutting sword, by the same token, won’t slice easily through plate armour (1). What it will do is transmit enough blunt force to scramble brains and rupture internal organs. The function of the sharp edge is to cut into the armour just enough to stop the blow glancing off and dissipating its force into empty air.

  The geometry of swords is a matter of compromise. Thin needle-sharp points penetrate best but are too frail for business purposes; if they hit bone, armour or the other man’s sword, they snap off or bend. Broad, thin cutting edges cut best, but are similarly weak. To cut, you need the most acute angle possible. The edge of a blade is a wedge forced into a gap of its own making; the thinner the edge, the less force required to drive the wedge in to the required depth. A razor blade cuts better than an axe, but you couldn’t chop down a tree with one, because it’d buckle under the force of your blow. Cutting swords tend to be wide, to make the wedge as long as possible. Thrusting swords are the same wedge turned through ninety degrees; they need to be narrow. They also need to be stiff, or else they’ll bend, like a modern fencing foil, rather than penetrate. Cutting swords should be flexible, capable of giving way and springing back under the tremendous force of impact. Stiffness and flexibility are governed by the blade’s cross-section. Nearly all double-edged swords, for example, have a cross-section roughly like a squashed diamond; the flatter the diamond, the greater the degree of flex. You can compromise by making the faces of the diamond concave arcs instead of straight lines. This accentuates the central rib, imparting stiffness, while reducing the angle of the edge, promoting flex. By a happy coincidence, it’s also the angle you get if you grind a sword lengthwise on a wheel rather than planing it down with a flat stone or a file.

  The earliest swords were double-edged. It’s easier to forge them that way. When you beat out an edge, you spread the metal, like spreading butter. The side you hammer on spreads, the other side doesn’t; therefore, the blade tends to curve, giving you the distinctive profile of the sabre and the scimitar. Trouble is, if you beat the edge out enough to make it thin enough to cut, you get rather more curve than you want, so you have to keep stopping and straightening. This process is hellishly awkward, as the blade tends to buckle and distort. You flatten it out and you think you’re home and dry, but as soon as you heat the thing up and quench it, during the heat-treatment stage that gives the blade its flexibility, the distortions you’ve so carefully beaten out of the steel somehow come back, and you end up with something looking like a two-dimensional corkscrew designed by M C Escher. In comparison, a two-edged sword is a piece of cake. You hammer on both sides, spreading the steel evenly. The blade stays straight of its own accord, giving you nice, wide cutting edges and a stiff central rib.

  Forging steel is all about spreading. A billet of red-hot steel is like a tube of toothpaste (with the cap on, of course); you can squidge it into the shape you want. If you pinch the edges, you raise the middle. If you squash one end thin, you fatten the other end, as toothpaste is forced backwards. A desirable quality in swords is distal taper; wide and thick at the handle end, tapering gently and regularly, narrow and thin at the point. Distal taper should come naturally as you work your red-hot flat-rectangular bar into a double-edged blade. You start at the point end and hammer your rectangular bar on the edge. This makes it narrower, but also thicker, as material from the edge is forced into the middle. So you flip the bar over onto its side and pound on the flat side, squidging your steel toothpaste up the tube. Then turn it back on the edge, to narrow it some more; then on its back, to thin it. As you work up the blade from point to hilt, you decrease the rate at which you draw it out, to get your taper. When you’re done, you should have a nice icicle shape, with a rectangular cross-section. Then you beat out the edges to turn the rectangle into a diamond. Compared to making a single-edged sword, it’s a walk in the park; and the customer gets the added bonus of a spare cutting edge, so that when he’s blunted his sword bashing it on some guy’s helmet, all he has to do is flip it round in his hand and he’s back in the cutting business again.

  The ancient Greeks were passable architects, not bad at sculpture, literature, philosophy and mathematics; they were fantastic metalworkers. They made a kind of double-edged sword that distal-tapers the wrong way—narrow at the handle end, widening up as far as the centre of percussion (if you lash out instinctively with a sword, the place on the edge that contacts the target is the centre of percussion) and then narrowing sharply to give a usable point for stabbing with. That’s good design. A curved edge cuts better than a straight one, which is why swordsmiths went to all the extra trouble of making sabres and scimitars. The Greek leaf-shaped blade has the advantages of the straight two-edged sword, but has curved edges, which cut better. Even more impressive was their other major sword type, the kopis or machaera. It’s a single-edge curved sword, but the sharp edge is on the inside of the curve; your basic hook, or sickle. This is sheer misery to make but works exceptionally well, since the concave curve tends to pull the cutting edge into the target, giving you a slicing action. The machaera is, in fact, the only pattern of sword still used by the military for killing people. Alexander the Great took the machaera to India, where the local smiths copied it. Nearly two and a half thousand years later, the
Gurkha mercenaries employed by the British army still carry and use the kukhri, which is basically Alexander’s sidearm of choice, but these days they’re made in Nepal out of recycled Mercedes lorry springs.

  Greek craftsmen made weapons to order for middle-class citizen soldiers who paid for their own equipment. The Romans were into mass production for huge professional armies. They copied a Spanish design; a short, broad double-edged blade, easy to make, wide enough to have thin edges that cut superbly, the edges running parallel for most of the sword’s length before tapering sharply to form a wickedly efficient point. The gladius Hispaniensis is an outstanding design, and Roman infantry tactics were founded on it for centuries. It cuts brutally but its primary purpose was stabbing. It’s very short—big deal, said the Romans; when we fight, we like to get close to the enemy—because if it was any longer it’d be too heavy to use. Swords need to be light. Two pounds is the optimum. Some two-handed medieval longswords weighed over three pounds, but they had long handles to give extra leverage, and they were so well balanced that they felt much lighter in use. Any form of swordfighting is exhausting work, and if you get tired and slow, you don’t stand a chance.

  When Julius Caesar fought the Gauls in the first century AD, he noticed how, in the heat of hand to hand combat, the Gallic warriors often had to stop and straighten their swords under their feet. Their swords were soft iron, not steel. The extraordinary virtue of heat-treated carbon steel is that it has a memory; bend it, and instead of staying bent as iron does, it springs back.

  These days, we know exactly how steel works. It has to do with the carbon content of the metal, which enables steel to change its crystalline structure when heated red hot and immediately quenched in water or oil. This makes the steel extremely hard, but also brittle—if you drop it on the floor, it might just shatter like glass. To make a flexible blade (which is basically just a spring with sharp edges) you need to reheat the hardened blade to a specific temperature and quench it again. Luckily for smiths, before the invention of thermometers, the steel itself tells you exactly when to quench it. It changes colour, running through the rainbow from pale straw yellow to purple to deep, then light blue. You quench swords at the dark blue point, to make them as springy and tough as possible while still able to hold a sharp edge. Or you can dip them in oil and stick them in the fire until all the oil burns off, or you can simply dunk them in molten lead, whose melting point just happens to be the same temperature as the blue stage; these processes are easier and more reliable, but far less aesthetically satisfying.

  To make steel, though, you need the right sort of iron—not the pure stuff, but iron alloyed with a small quantity of carbon. There were places where you could dig naturally-occurring steel-bearing ore straight out of the ground. The most famous deposits known in antiquity were in India—King Porus gave Alexander the Great thirty pounds of it—and came to be known as wootz. For the vast majority of smiths who couldn’t get hold of the imported material, making steel was a mysterious hit-and-miss affair. You were more likely to get steel if you recycled old iron—horseshoes, wheel tires—than if you used fresh ore, but it was a combination of luck and serendipitously-acquired skill, which wasn’t freely shared. What actually happened, of course, was that carbon from the charcoal universally used to fuel the smith’s fire until the Industrial Revolution migrated into the iron, but they didn’t know that. As a result, decent hardening steel was rare and precious, and only an idiot would dream of making a whole sword out of it.

  Instead, bladesmiths all across the world developed the technique now known as pattern-welding. Horribly time-consuming and requiring exceptional skill, pattern-welding was used for hundreds of years, until some point in the ninth century AD, simply because there was no other way of making a half-decent sword. Pattern-welding is based on the happy fact that when two pieces of steel or iron are brought to a temperature just shy of melting—you have to get it just right or the steel is ruined; it’s blinding-white hot, so you judge the exact moment by the soft hissing noise it makes—you can fuse them together by gently hammering. You can weld short bits together to make a useful length; you can also weld hardening steel to soft iron, which means you can make the body of the sword out of cheap, pliable stuff and save the rare, brittle-hard steel just for the cutting edges. Dark Age smiths twisted hundreds of iron twigs together and welded them into billets, then welded the billets into a core, then added the steel edges. The pattern part of the description refers to the swirls, waves, spirals and parallel lines that show up when you etch the finished blade with acid; an unintended by-product, but stunningly beautiful. A pattern-welded sword would have taken weeks to make, and only a deeply skilled man could do it—one mistake, one chunk of slag embedded in the fabric, one seam not heated up enough and failing to fuse—would ruin the whole thing, turning it into gorgeously-figured scrap. The end result was a conflict between two diametrically opposed materials, one soft and ductile, the other hard and brittle. A pattern-welded sword is a supreme triumph of skill, beauty and ingenuity, and it just about gets the job done. A blade beaten out of a SAE 5160 truck leaf spring will outperform it every time.

  Which leads us neatly to an assessment of the traditional Japanese sword, the katana. Most of the rest of the world got better, cheaper steel which allowed them to start making all-steel swords, but the Japanese didn’t, and so stuck with pattern-welding. They used tamahagane, steel smelted out of volcanic black sand, welded to a soft, multiple-folded iron core. The katana is single-edged; so, in order to make it strong enough not to bend or break, it has to be thicker in the body than practically any other sword type. To control and handle such a chunky, heavy object, the Japanese opted for a relatively short blade and a long, two-handed grip. The curved blade is ergonomically suited for cutting, particularly the draw-cut (where you pull the blade across the enemy’s flesh to slice rather than chopping at it); it’s got a point, but one that’s primarily designed to assist with cutting with the tip rather than thrusting. All in all, the katana is a clunker, an Edsel, fossilised, self-circumscribing, only capable of being used in a limited number of ways, and not much of a stabber; beautifully-made, because only the nobility were allowed to own them; rather like the traditional English game-shooting shotgun, still handmade by craftsmen in a fashion that’s hardly changed since the 18th century, a joy to look at and handle; but a mass-produced Remington slide-action kills birds just as dead, handles just as well, has three times the firepower and costs 1,000 times less.

  The myth of the semi-magical Japanese sword arose after WW2, when GIs brought captured katanas back from the Pacific, and their sons started playing with them. This led to the Western discovery of the Japanese tradition of swordsmanship, which was unique in one vital respect; it was still alive. By 1945, sword-fighting was dead in the West. There was no living tradition; if you wanted to know how to use anything more practical than a bit of wire in a dish-shaped handle, you had to learn it from a book, which you’d have to go to a museum to read. The Japanese tradition, by contrast, was unbroken back to the 14th century. By the same token, the Japanese had been fighting with basically the same sword design for 600 years; hardly surprising, therefore, that they were about as good at it as it’s possible to get. The katana isn’t a particularly good design, and kenjitsu isn’t the supreme martial art; but by the second half of the 20th century it was the only game in town. The only swords apart from katanas that an American would-be swordsman was likely to encounter were 19th century military sabres, designed primarily for use on horseback, for chopping at the heads and arms of footsoldiers; good enough for that, not much use for anything else, heavy and forward-balanced, extremely unsuited for anything resembling scientific fencing. No wonder, therefore, that to the post-war generation, the katana was a magical object possessing practically supernatural qualities.

  These days, there are scores, hundreds even, of swordsmiths working in the USA who will supply you, for the price of a decent desktop computer, with the best swords
ever made. They’re better than anything produced in antiquity because they’re made of modern steel. Demand, based on the revival of interest in the Western martial arts, has been sufficient to justify outsourcing medieval replica sword manufacture to China. So, for around two hundred dollars, you can have an American-designed replica of a medieval sword, made in China out of 5160 steel, that’s better in every meaningful respect than the finest blade ever commissioned by the Kings of France. You’ll never use it, of course. You might slice into a water-filled plastic bottle. You might even dismember a 50 gallon oil drum, and post the ensuing carnage on YouTube. But the masterpiece you hold in your hand is obsolete at the moment of perfection. All you can really do with it is look at yourself holding it in a mirror, in the same way as a zoo lion stalks in his cage, glorying in his absolute possession of seven paces.

  No offence intended to the bottle-choppers. It’s entirely thanks to them that we have any insight at all into European swords and swordsmanship in the Middle Ages and the Renaissance. In the 19th and 20th centuries, before the Society for Creative Anachronism kick-started the re-enactment hobby and made it possible for grown men to earn a living making faithful reproductions of old swords, all manner of weird myths had grown up about the medieval European sword. It weighed ten pounds. It was basically a heavy iron bar for bashing with. There was no skill involved. It’s not hard to figure out where these misconceptions came from. The number of surviving medieval swords is quite small, and they tend to be in museums, where you’re not allowed to take them out of the case and play with them, to see how they handle.