I have in mind a new sword. This sword has four cutting blades, think like a double-edged sword, but two of them, perpendicular to each other. It looks like it would be a thrusting weapon, which it could do just fine, but I want it to slice. I was contemplating something like several tiny hinges. For example if you would slash, the penetrating blade and its parallel would remain rigid and unyielding while the perpendicular blades fold back against the opposite blade. Hopefully this would allow a good slicing weapon for multiple directions without the user having to turn the blade too much. Practicality isn't quite as important when it comes to "Is this the best weapon for the job," but if there are already existing weapons that would be better, please mention them!

Potential Concerns:

  • Would the blades need to be thinner to allow a cleaner cut, resulting in potentially weaker blades that break easily.
  • Would it be necessary for a wielder to develop a "slice partially then withdraw" style of combat? I imagine the blade would be significantly thicker at the center because of the three blades and thus harder to cut through things.
  • Would creating folding blades be too technical/difficult for a smith or machine to pull off?
  • Would hinges decrease the longevity of this weapon, resulting in more maintenance and a higher chance of being outright broken? Is there a better method of creating folding blades?

For this question you can assume that the blade can be "instructed" on which blades to allow to fold via magic/unknown technology, but feel free to analyse how this would work without magic. You can also assume an advanced level of technology but the closer to current Earth, the better. For the rest of the stuff, try to be as close to a real world sword as possible with comparisons. I can only shrug off so many physics facts before people close the book and utter "nonsense" before throwing it into the fire.

BONUS: Can we make this into a whip sword?! That'd be sweet. If not that's fine too.

  • $\begingroup$ Lol. I feel the love. But you have to admit, if you did think it would work, you'd want one! $\endgroup$ – JGaines Mar 24 '16 at 2:39

Swords and edged weapons in general have evolved into their present shapes after at least 5000 years of evolution, so there are several good reasons why a sword such as you suggest isn't a good idea. (You also need to suggest what sort of opponent you are facing i.e. armoured, mounted or dismounted, using a similar or different weapon, in order to fully judge your idea: weapons are not developed in isolation from the defense).

The first one, just based on the description, is this will be significantly heavier than a single bladed weapon. The wielder will have to use more energy holding it and fighting with it than a conventional blade, so will tire more easily. If you stay out of the way long enough, the user of the quadblade will let his guard down and you step in for the killing blow.

A larger, heavier weapon also has more inertia. In some instances, this is a good thing. Smashing weapons like maces and war axes use the considerable mass to add power to the blow, smashing through armour and into the person underneath. On the other hand, swordplay involves rapidly moving the blade both to attack, defend and to confuse the enemy as to where the blade is going to be. A larger, slower moving sword isn't going to have these advantages, and will require considerable effort to change directions to parry an incoming thrust.

Finally, the system of springs simply adds complication and more weaknesses to the weapon. Hinges could seize due to the force of impact during swordplay, leaving the auxiliary blade stuck out or folded back when you don't want it to be. With enough force, the hinge could break right off, and you weapon is now unbalanced because one of the blades is missing, something which will be rather difficult to recover from quickly.

Finally, mastering a complex weapon takes a lot of time. Looking at instruction books from the Middle Ages for fighting styles with sword and dagger, sword and cloak or Japanese Niten Kai two sword systems you see they are significantly more complex than using a single blade or blade and buckler. Japanese military swordsmanship eventually was pared down to a very utilitarian style (starting in the Meiji Restoration) to make it easier to teach large numbers of troops and for them to learn. A quadblade will require a specialized school to try combinations and practice them against different sorts of opponents, so the weapon could be used effectively against all comers.

So this is the "negative" answer, thousands of years of trial and error have created exquisite weapons to deal with many styles of fighting, all kinds of armour and changes in technology.

  • $\begingroup$ Yeah, I figured as much. While I was putting it together in my head it was able to fold back far enough so that the blades weren't hindering the slice. Of course, that didn't seem practical in reality thus the question. A real life equivalent might be closer to an axe because of the weight and wedge shape the folding blades would make. I do think though, that a different style of fighting could be adapted if it were more plausible as a weapon. I'll probably still use it as a model that works using some sort of magic or tech, but this was still really useful! Thanks! $\endgroup$ – JGaines Mar 26 '16 at 22:52

No, this would not work

What makes a sword is a long slicing weapon. This monstrosity you have created would not work, it just wouldn't.

  • Thinner blades would not work, because you are still going from thin to thick. There is no getting around this, if you made the blades thin enough to cut you couldn't connect them to the blade without them breaking off.
  • You'd do better with a mace or other pointy object on a stick. This thing will be unweildy, and in order to hit someone you have to have your sword at the right angle, like with all swords. But the extra two blades you glued on stop the sword from cutting any deeper than about an inch, which means you've ruined your sword's slice, with no benefits from it.
  • The hinges, in order to be sturdy enough, would be too large. In fact, nearly anything extra would be too large. Swords need to be smooth and thin on the ends, so they will cut well. Hinges for extra blades would simply not work.
  • Yes to the first question and no to the second


Again, slashy things! Slashy things need their strength, which you have just deprived it of. Also, there is no way to make your sharp blade move without making some kind of scaled thing, and then the areas where they connect will be awful.


Instead of hinges, let the blade which is perpendicular to the guard flex at the end, getting out of the way of the penetrating blade during slashes.

The purpose of the second, flexible blade is to enlarge puncture wounds, increasing the likelihood of hitting a major blood vessel during a stab. For that purpose, the second blade needs to be rigid to forces approaching from its tip, but does not need to be that rigid when force comes at it from its side. If either blunt side strikes flesh obliquely, while its harder companion blade is cutting deep, it should just bend out of the way, sliding along the bloody flesh.

To obtain this, the flexible blade could be made of thin aluminum while its companion is hardened steel or titanium. They would only be joined together into a welded cross for about half the cutting length of the sword, from guard to mid-blade. After that point they would float perpendicular to each other, without reinforcement, so that flexing blade can move freely.

It is not quite what you asked for, but it has the advantage of durability. The hardened blade will still battle ready, even if the flexible blade snaps off.

  • $\begingroup$ The flexing blades is actually a really good idea. I'm trying to think of a way the metal could flex without also being easily bent or broken. Have there been aluminum blades before that you know of? $\endgroup$ – JGaines Mar 26 '16 at 23:01
  • $\begingroup$ Sorry, I'm just an idea guy. I don't have an metalurgic or historic knowlege. Anyone else care to answer @JGaines? $\endgroup$ – Henry Taylor Mar 27 '16 at 21:22

Would the blades need to be thinner to allow a cleaner cut, resulting in potentially weaker blades that break easily.

Once folded you're 3 times as thick as whatever thickness you started with. This isn't a thin vs thick issue. It's a going from thin to thicker issue. Even if you do it smoothly, you're still attacking them with a wedge. Folding blades and wedging flesh apart costs energy. If you're looking to be able to chop limbs off this isn't the most effective way to do it.

Would it be necessary for a wielder to develop a "slice partially then withdraw" style of combat? I imagine the blade would be significantly thicker at the center because of the three blades and thus harder to cut through things.

I presume this is a "Hollywood" weapon, meaning the most important thing is to look cool, not to be effective. Otherwise, I'd point out that piecing has been known to be the most effective way to use a sword since before roman times. So no, you don't have to even have slicing in your combat style, quad or not. Why quad then? You could explain away this design by claiming it's a "ceremonial" weapon.

Would creating folding blades be too technical/difficult for a smith or machine to pull off?

Depends on the smith and how complicated your design ends up being. You have me thinking of playing with piano hinges at the hardware store.

Would hinges decrease the longevity of this weapon, resulting in more maintenance and a higher chance of being outright broken?

All moving parts come at a cost.

Is there a better method of creating folding blades?

Consider not folding the blades. Consider rotating one blade. You mentioned magic/technology. Let's create the world's first sword/blender. Why? Because it's fun to twist the knife.

Will it work?

It's still a sharp pointy stick. I wouldn't buy one but if you came at me with one I would definitely start paying attention.

  • $\begingroup$ Yeah, piano hinges were along the lines of where I was headed with hinges. I think if there were a flexing metal it would probably work better, but sadly I can't really think of any that would do that. Although, having a blender on a stick is both grotesque and awesome! I will have to consider that further... $\endgroup$ – JGaines Mar 26 '16 at 22:56

...if there are already existing weapons that would be better, please mention them!

Yes, there is something which has been actually developed and is in use. It would be one of your worst nightmares to get stabbed by it. It is called Jagdkommando. Here's an image.

enter image description here

Also, why would you need to add two other (perpendicular) edges to your sword when a sword with a single edge does a mighty fine job. A single-edged blade would cut much faster than than the design your proposed. Your design would have been an improvement if it offered better chances of contacting your adversary in combat.

Unless you offer that, I would like to stick to a katana blade. Thanks.

enter image description here

This is far more practical and deadly in combat than your design and the Jagdkommando.

  • $\begingroup$ While a bit short to be called a sword, this Jagdkommando is about the right size to be a whip handle. So it could be made into a kind of "whip sword" as the OP requested. $\endgroup$ – candied_orange Mar 26 '16 at 12:41

The other responses highlight why your idea is not effective, so I will address alternatives.

The deployed part of your design, where blades are perpendicular to the main edge, is used on a variety of polearms, including the classic halberd or the bec de corbin. The idea here being that the wielder can use it as a classic thrusting spear, while also allowing it to be used with a sweeping motion as a warhammer or warpick.

Your idea initially reminded me of a mechanical broadhead point, where the extra blades deploy on contact. Perhaps an oversize deployable broadhead on a polearm would fit your idea. This, of course, is treating your creation as a thrusting weapon only though. As the others have noted, the mechanical aspect of this could prove unreliable and even detrimental in the course of combat.

Going off your "Can we make this into a whip sword?!", whips and whip-like weapon are generally thin and lightweight. Their advantage is the extended reach and unpredictability. The disadvantage is they are often needlessly complex for a simple "I'm going to stab you with this" action. The even greater disadvantage is they are extremely difficult to use effectively and safely. Hook swords, or tiger swords, are dual wielded swords with a hooked tip. This allows some creative fighting techniques, such as catching an opponent's weapon or limb. It also allows them to be linked together, using the bladed handguard on the outer sword as the slicing edge. Another interesting weapon is the urumi. These are flexible, often multibladed weapons similar to a metal whip. Although very difficult to wield, they have the advantage of being concealed as a belt.

So though your idea as it stands may be impractical, but there are some real world examples of various aspects of your design that you might examine.

  • $\begingroup$ When I was thinking about a whip sword the way I was thinking was a segmented body, that didn't really have the reach of a full whip (maybe about two and a half the length of the blade normally), but was still somewhat intimidating because of the weight. And because it has four blades instead of two, skill would be less of a factor. Primarily you'd just be trying to catch your opponent off guard and dealing extra damage with gashes, that may or may not add up over the course of a battle. $\endgroup$ – JGaines Mar 26 '16 at 23:09

One thing to consider is whether the perpendicular blade should be raised by default. Imagine a double edged sword made from two steel layers that twists to form the four edged blade on demand (what rational "demand" I have yet to fathom). A fairly simple scissor style mechanism would be less complex than a hinge and more structurally sound.

Imagine two separate thin pieces of steel that are pivoted like a pair of scissors. Normally they are milled such that they sit flat against each other like a normal sword. Normal slashing, parrying and stabbing action would be possible. In the heat of battle, the hilt can be twisted such that both pieces pivot 90 degrees to form the quad blade.

I can only imagine that you would do this just before a thrust into an unarmored opponent, with their guard down to maximize the size of the inflicted would. For piercing armor I think a double edged sword would be be more effective as it would generate less resistance against the armor while maintaining more strength in the blade. "Twisting" the blades would almost immediately telegraph your intention though, and add an split second to your attack.

One last potential use for the quad formation, may be to increase the realized coverage of the blade in more than one directions (for shielding or parrying). This would only be marginally better than a normal two bladed weapon and only against multiple opponents (projectiles).


Are you basing your sword idea on trefoil swords? They were used by French cavalry during the Napoleonic wars, and are some of the best stabbing swords ever designed (they make an entry wound that is very difficult to sew up properly). The disadvantage with this type of sword is that they do not cut very well; in fact many of them did not even have a sharpened edge to cut with because of how bad they were at cutting.

The four-blade design you want would be even worse than said trefoil blades because any folding hinge assembly small enough to not get in the way of your cutting would break far too easily.

If you want to use a weapon that can hit from any direction, get a light sabre, morningstar, or flanged mace.


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