There are many weapons that appear in fantasy that are unrealistic for use in combat, from Cloud's sword in Final Fantasy to Daedric weaponry in Skyrim. One of these (less-than-realistic, in this case,) weapons is the whip sword, a simple sword (i.e. a Katana, Gladius, etc.) that at the press of a button or pull of a lever turns into a whip covered in sharp blade sections.

Obviously this weapon is unfeasible... Or is it? Could the whip sword be built and if so, how early could can it be built and how effective would it be to use in combat?

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    $\begingroup$ Even though this question is asking about a very specific case, answers to this question will probably provide some insight into this sort of thing for fantasy-type or unusual weapons in general. $\endgroup$ Jul 20, 2016 at 18:53
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    $\begingroup$ A weapon like this is featured in the Sandman Slim novels, and include some detail of the internal construction, care, qnd cleaning. $\endgroup$
    – JDługosz
    Jul 21, 2016 at 3:38
  • $\begingroup$ Feasible whip sword design: start with a foil, break into small bits, connect bits with flexible joints, run bits over grooved plank, connect all bits together in continuous loop that can slide in plank groove, install in hilt a small combustion engine to pull bits around plank. Name sword "Texas Chainsaw Massacre". $\endgroup$ Jul 21, 2016 at 5:14
  • $\begingroup$ I am surprised no one mentioned Renji's sword so far (from the animé Bleach). $\endgroup$ Jul 22, 2016 at 3:20
  • $\begingroup$ There's a related question to this. I forgot which one. I gave an answer to it. $\endgroup$
    – Hazard
    Mar 26, 2018 at 23:19

12 Answers 12


In my experience, the effectiveness of a weapon can be broken into four different categories. These are Ease of Construction, Lethality, Required Skill, and Usefulness, each being more important than the last (usually).


I think anyone who has every played Soul Caliber has thought about building one of these Whip-Swords, or maybe that was just me. Either way, it seems quite difficult. Normal swords aren't difficult to manufacture (we'll see what kind of debate that statement sparks) but they do require some level of skill. A truly exceptional blade would require a master smith to produce, but average blades can be made by less skilled craftsmen. Our whip-sword is likely going to require the master no matter what quality weapon we want.** The mechanisms inside the hilt that allow for the whip to be released (and retracted?) are going to be mildly complex, and the fastenings involved with the cord and the blade segments will require a fine touch. With practice this weapon may become easier to manufacture, though, and it would not be impossible, so if the weapon were truly superior to the easier-to-make weapons, it would be worth the time and effort, which brings me to my next point.


Most weapons kill or wound their targets, and the methods behind this vary greatly (arguably the most-studied thing in history!). As a sword, our whip-sword would be like any other but as a whip this weapon will either bludgeon/hack at the target or slice the target depending on the weight of each segment, the orientation of the blades, and the speed of the swing. Hacking and slicing are both pretty familiar, and both are fairly lethal in their own right. Hacking in particular is lethal, brutal, and effective, but slicing requires more finesse to be fatal, which brings us to the next category.

Required Skill

Here is where things get dicey. A weapon can be super lethal, but if no one knows how to properly use it the weapon will never be used. An excellent example of this in history is the crossbow vs. the longbow. Crossbows were inferior weapons by all rights, but they replaced longbows in many scenarios because the training required to become a proficient longbowman is extensive, while pretty much anyone can fire a crossbow. The whip-sword will likely require immense training to be a truly deadly weapon; much like nunchaku, an untrained person would likely hurt themselves or their allies rather than the enemy. Normally this would mean the weapon was impractical, but there are examples where this isn't the case. Longbows remained in service for quite some time because even though crossbows may have been easy to use, the longbow had many practical advantages over its competitor, like longer range and faster fire rates. And thus we come to the last point.


All of the above categories serve to support this final category. No matter how easy to make, lethal, and easy to use, if a weapon has only one single, specific application it will not be an effective weapon. Our whip-sword would seem to have two possible applications. The first is simply as a sword, and we know how those are useful already, though the whip-sword might be slightly less effective than a regular sword on account of the weakness of the joints between segments. The second is as a flail-type weapon. Depending on the length of the whip, the weapon might be useful at medium range. If the weapon allows the blade to be retracted back into a sword, these two applications might combine rather well, allowing the wielder to engage the enemy at longer range until they close at which point the enemy could be engaged with the sword. The whip would probably be dangerous and ineffective while fighting in a melee or in a battle line, but the sword function remains. It could also be effective on horseback, perhaps, though I shudder to imagine what would happen in imperfect conditions. What's truly important here, though, is that warfare is a famously fickle beast. The set of possible scenarios is probably uncountably infinite, and if someone were to think of a situation where the whip-sword were especially useful that could make a huge difference.


So where does that leave us? Compared to the sword, the whip-sword would be more difficult to make, about on par for lethality, far more difficult to use, and would be applicable in slightly more scenarios. But would it ever be used? That's debatable, but it definitely could be used, and I feel like that's the important part.


**You also asked when this weapon might be built. If we wanted the weapon to be able to retract back into a sword then I'd say probably the early Renaissance, though I'm no expert on such things. The metallurgy existed for the construction, chain or wire existed for the cord, and a simple release mechanism could be built using Roman-era technology. The retracting would require a spring, however, and coiled springs did not appear until the 15th century.

  • $\begingroup$ Questioner says "at the press of a button or pull of a lever turns into a whip", not that it does the reverse so easily :-) If retraction turns out to be technologically the hardest part then perhaps the Roman-tech version of this weapon, that you have to retract by manually winding up the wire, could be upgraded, once early Renaissance-tech is achieved, by the addition of a spring retraction mechanism! $\endgroup$ Jul 20, 2016 at 11:49
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    $\begingroup$ As a novice smith I can assure you that even a simple sword is a bit more complicated than your answer would suggest. $\endgroup$
    – James
    Jul 20, 2016 at 20:54
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    $\begingroup$ Something I'd point out: swords are almost universally one solid piece of metal, which helps a lot with the whole practice of hitting things with them. Having your sword be in a dozen or so segments held together by a single tight cord brings up some structural integrity issues for the sword mode. (Let's presume the segments even stay aligned properly.) That might change how it's used and the skill required as well. One could compare that to just carrying a good sword and a good bladed whip. $\endgroup$ Jul 21, 2016 at 0:33
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    $\begingroup$ Look at microblade neolithic technology. Individual obsidian rasors were set in a handle. Experimenting with strips of leather instead or getting inspiration from the spine bones of an animal might be more natural to a culture that did not make swords in one piece. $\endgroup$
    – JDługosz
    Jul 21, 2016 at 3:41
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    $\begingroup$ I would add "ease of maintenance" into your list of important attributes for a successful weapon. The AK47 is a well-known and effective weapon largely because it is easy to maintain. It doesn't require much skill in the hands of the user to keep it functioning, certainly not when compared with other similar rifles. This factor, more than any other, would be the downfall of a whip sword -- I would anticipate that such a weapon would be both easily damaged and difficult to repair: not a good combination. $\endgroup$
    – Simba
    Jul 21, 2016 at 13:03

While not exactly what you are describing, flexible blades (or sharpened steel whips depending on how you look at it) are a thing that have existed and have been used in combat. The most notable of which would be the Urumi used by the Elite Rajput warriors. They are relatively primitive weapons and not really designed for armor penetration so much as dismemberment. They have existed since Mauryan Indian and as such they should be easily feasible for most medieval cultures. If you want a mechanical mechanism where a blade goes from rigid to whipped, that will be harder but should be possible with early renaissance technology.

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    $\begingroup$ I like this Urumi blade, +1 for that. $\endgroup$
    – XenoDwarf
    Jul 19, 2016 at 23:30
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    $\begingroup$ "should be possible with early renaissance technology" But such a structure would not be very durable. Given that swords are often endure harsh "bashing" (for example during a parry), I would hazard that it would not be very effective. $\endgroup$
    – Aron
    Jul 20, 2016 at 3:47
  • $\begingroup$ from which one might be able to derive a sword made of meta materials which exposed to magnetic field or another effect switches between two phases, one hard like a sword and one flexible like a whip $\endgroup$ Jul 20, 2016 at 16:09
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    $\begingroup$ @Aron But then again, how much of the combat style is based on how the weapons are intended to be used? Would someone with "whip sword" subject their weapon to bashing during a parry? As a more extreme example, a longbow probably wouldn't hold up well to bashing in a parry, but that wouldn't be a problem, because it wouldn't be used in that fashion. $\endgroup$ Jul 20, 2016 at 19:24
  • $\begingroup$ A cat o' nine tails is very similar to an urumi, except that it does not have blades. It is a type of whip which was used as corporeal punishment all over the world until very recently. en.wikipedia.org/wiki/Cat_o%27_nine_tails $\endgroup$ Jul 21, 2016 at 16:39

The "whipsword", in theory, should be feasible to build, but using would require a lot of practice.

In fact, I've designed this on paper once, but didn't have the resources to build and test it at the time. I'll redraw and share the design here now (Using semi-gladius shape as base):

In the locked position, it would look very much like a normal sword, but with small lines separating each individual section (See Figure 1).

Figure 1

A button could be placed on the bottom of the handle in order to "lock"/"unlock" the weapon. This button could also potentially be designed as a trigger where the index finger is placed - in fact, how the mechanism is activated is almost completely up to you as the user.

What this "activation" would actually do is simple: When pressed in the locked phase, it releases the lock on a spool of wire, allowing the pieces of the sword to extend and flex outwards (See Figure 2).

Figure 2

Each piece of the swords would be designed to allow the wire to run through it - with the exception of the tip piece, which would secure the end of the wire (See Figures 3 & 4).

Figure 3 Figure 4

In order to help align the sword pieces properly when retracting the wire, instead of using a circular wire, use a flat piece of metal, aligned perpendicular to the edge of the blade (Refer to Figure 3 & 4). By using the flat piece of metal, you can help "influence" the direction which the blade will flex in. Since it's aligned perpendicular to the edge, the blade will be inclined to curve in 2 specific directions - the edge directions, which helps to allow for easier slashing using this weapon while unlocked.

When the button is pressed while the sword is in an unlocked state, a motor is activated, spinning the spool of wire and pulling the sword back into a straight state. Normally, in order to keep the sword pulled taut you would need continuous force from the motor - however, if we add an extra locking mechanism into the handle/cross guard to keep the sword taught, we would be able to save energy (be it batteries you're using or magic) (See Figure 5).

Figure 5

Based on this design, the earliest you could build it would be whenever your story first creates motors and has access to some basic circuitry - rope could replace the thin metal wire if your society does'n't have that yet. Would it be unsuitable for combat? That really depends on how well trained you are with the weapon. Is a pencil unsuitable for combat? Normally not, but with a bit of creative thinking, the Joker has proved to us that even a pencil can be a dangerous weapon.

(Now excuse me while I go and scavenge for parts to build this thing)

  • $\begingroup$ I've seen a VERY similar weapon in pacific rim ;p $\endgroup$ Jul 20, 2016 at 0:33
  • $\begingroup$ @JourneymanGeek The pacific rim version of this isn't really a whip - It seems to be designed for compact storage and extending out of the blade, and doesn't extend nearly as far as if the sword were using this design. The drawback to this design is that the sword, while fully "retracted", is full sword length, so it can't be hidden. The pacific rim version also has a different locking mechanisim - the PR version has a lock between each piece, whereas this design is simpler and relies on the wire locking to provide the tension keeping the sword taut. $\endgroup$
    – Aify
    Jul 20, 2016 at 1:08
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    $\begingroup$ Why not a lever-action retractor? If the handle is two-handed, a reasonable mechanism could be devised based on hinging the handguard at the pommel. Or even a pullcord using the pommel. $\endgroup$
    – Nij
    Jul 20, 2016 at 6:56
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    $\begingroup$ Two short wires attached to conical pins on either side of the central hole on each section keeps them all separated the same distance, and allows the force pulling them back together to align them again properly. A lever / twist handle would allow it to be pre-electrical (and relatively easy to make). If each section had the wire in a ⋔ (Y with a central line) then it could pull a little more solidly, and if the arms went through a hole in the center of the main wire then it would allow for more yawing flexibility too... The trick would be entirely in the use of it ;-) $\endgroup$
    – Rycochet
    Jul 20, 2016 at 8:18
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    $\begingroup$ This IS the answer. I wanted to answer something like that but i was too late :p $\endgroup$
    – Nico
    Jul 20, 2016 at 14:51

The quality of metallurgy to create flexible cables was not present in the medieval period, so real medieval weapons with flexible components used leather or chain. A hollow blade structure with a chain through it would be quite large and heavy. A blade with a leather or fibre rope through it would be hard to keep together tightly as the rope creeps and expands or contracts with humidity, and prone to being severed if another blade came between the segments.

Note that while flails existed including ball flails, and whips with light cutting blades scourges on them, heavy spiked balls on chains and other such weapons are fantasies which would be very hard to use without self harm.

Also the weapon would fail to work as a sword except for light draw cuts. Thrusting swords require a high degree of rigidity to punch through armour. Heavy cutting swords rely to a large degree on the harmonics of the blade to transfer energy to the target and not the wielder's hand ( there is a node at the hand, a node at the target about 2/3 of the way along the blade, and antinodes about 1/3 of the way along and at the tip - this is called finding the percussion point and if you don't do it when hitting hard, it bounces off and you drop the sword or sting your hand).

  • $\begingroup$ It's really strange to me that this is the highest-voted 'no' answer. $\endgroup$ Jul 20, 2016 at 14:39

As with all weaponry, context is everything. How do you intend to use this and against what kind of opponent? Single combat or against groups, with or without your own companions?

This would not be a very effective weapon. The blade would be too weak as a sword and unwieldy as a whip (keeping blade alignment as a whip would be impossible).

You could possibly use this in sword form as a slicing weapon for push or draw cuts against unarmored opponents, but the added thickness to the blade from the requisite internal cable would inhibit effectiveness. Chopping would be more appropriate to thick heavy blades, but segmentation would render the blade too weak and risky - likewise stabbing would need to guarantee perfectly perpendicular alignment at contact with a stationary target to reduce the probability of damage to the sword (or the blade just flopping over if the force of impact exceeds the tension on the whip before the strength of the armor).

As a whip, it might intimidate inexperienced raw recruits frightened of the novelty. If fighting alone against multiple unarmored opponents, a whip with blade segments distributed along it might keep them at bay for a short period of time. It couldn't be expected to do more than superficial damage to unarmored opponents as it cannot put consistent force behind the chunks of unaligned blade on a rope, which rather limits its usefulness in a martial application.

A slightly more plausible construction would be a solid blade until close to the tip, which is then like a single weight at the end of the whip which extends out the end of the blade. More of the blade would increase effectiveness of the whip with greater weight at the end (this is really a flail rather than a whip), but increase the structural weakness of the sword (anything farther from the hilt than the point of separation is not structurally reliable). The best placement for separation would be just beyond the point of impact - a thick chopper with a good point of percussion would limit the harm done to the usefulness of the sword.

All in all, this would never be more than an ineffective novelty. Time the release right and you might get a swing which is blocked, but the end unexpectedly flies off into the face of the enemy - if they don't have a visor down it might cause enough damage to improve your chances in a duel. Of course, then your sword is less useful having a chunk of the end hanging on a rope sticking out of it until you can manage to wind it back up (of course the silliness of having a spool of cable/rope on the pommel would be fairly ridiculous too).


This depends on how far down the spectrum of whip swords you go. The most basic is very feasible, a plain whip dotted with small light-weight blades, but not quite what you are referring to.

You could certainly create a length of pipe slotted together like curvy Lincoln Logs. Add in spring-locks which disjoints the fittings and weld each section to a link on a chain inside the pipe. Likely you'll have to weld the pipe together from two parts or engineer some fancy technique. The lock mechanisms will likely need a smaller internal cable as well, leading to the trigger at the hilt.

Finally you'll have to do some more welding/fusing to add blades to each section or carefully beat one side of the pipe sections into blades.

With that basic concept, it would better to start off with more engineered fittings. Improved designs would, for example, have folded steel fused into a triangular-esque piping fluted to a blade in one direction.

With more thought into the design of the locking mechanism and notch-work, the sword will be less likely to jam or suddenly ricochet into your face when you try a whipcrack.


In sword fights, metal swords can and do break. A fully metal sword. A whip sword, as depicted, would only be as strong as the spine. The whip sword isn't direct impact - the segments will torque the spine, depending on the length of the segments. Essentially, this would apply more force on a weaker spine made of less material.

The problem with ceramics and carbon is that they are brittle and would shatter or that they are bulky - carbon is stronger by weight, but the density would result in a 2 meter thickness.

Swinging weapons require too much timing. High level Kendo masters will step in to striking range, raise the blade and then strike hard enough to breach metal armor in just over 100 ms. With the average human reaction time of 250 ms, the substantial disadvantages of a swinging weapon timing would add to this disadvantage.

The sword part of the whip sword is useless. The whip part is defeated by rudimentary armor.


I would suggest that it is not so unfeasible.


Let's take what we got these days: a very exact, big CNC machine which is able to create the individual pieces of the sword to very, very high accuracy so they lock into each other very tightly. Then you pass your "whip" through holes spaced "just so" and make it so it pulls the tip towards the handle very, very tightly. If you can get enough pressure, the sword will be stable enough.

There are real life swords (e.g., Katanas) that are not supposed to hit anyway, but which do their damage in a slicing motion. This puts very little, or in the hands of an expert, almost no pressure on the sharp side of the blade (since that would nick it and make it unsuitable for slicing). So the internal cable does not need to excert inhuman pressure at all.

Building it in the "olden times" when you actually had to hammer out your sword might be another issue and there was no effective way to saw/drill the pieces. I can't really see how that would work back then.


It will be as effective as a Katana, as a baseline. So it depends on the opponent. If he is as armoured as the Samurai in the height of their time, you will need an expert swordsman to do much damage. But this is the same for any other sword.

The effectiveness of the whip variant will be some added benefit simply because of the surprise factor. Say you are fighting against someone who is an expert in Katana-style fighting, then he will be quite unprepared against a sudden whip appearing out of nowhere. Useful applications would be to choke/strangle your opponent, or to pin down appendices (say, the sword hand) while going to town with secondary weapons, at least. Of course, getting flung some of the sharp blade pieces in the face won't be much fun either. All of this happening from a distance larger than expected.

  • $\begingroup$ katana have very easy edge alignment in a cut, this is the opposite it is basically impossible to maintain edge alignment. $\endgroup$
    – John
    Jul 26, 2021 at 4:44
  • $\begingroup$ @John, sure! Maybe a future engineer would come up with some plan to make the inevitable little joint "fault lines" extra devastating (i.e., as little sawteeth or something along those line, for a good slice + rip action)? $\endgroup$
    – AnoE
    Jul 26, 2021 at 7:40

The humble spring steel measuring tape is quite capable of inflicting injuries if you retract it too quickly; if you built a version that was a bit stiffer and had sharp edges, and a heavier tip, it could inflict serious injuries on unarmoured opponents. Or you could add sub-blades or serrations.

The main advantage of the steel edged whip / weaponised tape would be a compact, concealable weapon that can be extended to hit targets out of arm's reach. It's very effective to have a sword that's longer than anyone else's.

The main disadvantage is the lack of stiffness. Even one of the segmented solutions others are talking about would not be as stiff as solid metal. That would make it hard to parry with and risky to maintain any kind of 'guard' with - as soon as it bends your opponent can attack. It would also not be very durable; spring tapes are easily kinked at which point they stop retracting properly. Again, segmented solutions would be vulnerable to damage to segments.

The other disadvantage would be unpredictability; without careful training such a weapon could be almost as dangerous to the wielder as the opponent.


I think it would be quite possible to make today, but rather difficult to construct with early technologies. I've done some pondering and to me it seems the hardest part in constructing this would be having the segments stay apart from each other and not just slide all the way to the end of a wire, once the mechanism is released, due to the momentum of swinging it. It would have to implement some sort of locking mechanism to keep the segments apart. And i think i have figured just the thing. This is a rather crude mock up. Whip Sword Cross-section

This is a single segment that would be in the default state, each pin (red) is pushed into the segment before and after with a spring (purple). the wire (black) is locked into the left side pin and looped around the right side one, like a pulley.The first segment's pin could be magnetically locked into the handle of the sword, or else wise if using earlier technology.enter image description here when the locking mechanism is released the sword when swung would then be able to extend using the extra wire between the pins moving them like so. The tension of the springs would have to be high enough that the sword would return to normal shape after a swing, but low enough that the momentum of the swing would separate the segments. As for ease of use and effectiveness, maybe if you are a skilled swordsman fighting against and unarmored peasant. But anyone with combat training would just bat the thing aside and stab you. Fancy and cool looking, but not a feasible weapon.


This is useless as a weapon.

Can it be built using modern technology, probably, the problem is it will be fragile and useless as weapons.

As a sword it is useless at best suicidal at worst.

Joints in a weapon are bad especially a rigid weapon like a sword. Even more so if these joints need to mechanically rigid in any directions(as opposed to a simple chain), which this does if you want to keep the only sharp edge pointed at your target. As a sword this thing is not a sword it is a sharp spring club under perfect conditions. it is pile of spraplel under most real conditions as the joints are subject to a great deal of shear strength and making them stronger just increases the stress becasue they get heavier much faster than they get stronger. joints like this will quickly fatigue until they fail, and a weapon that breaks while you are using it is worse than useless. Mechanical joints in rigid weapon are a problem waiting to happen. Think of it this way even professionally made swords, made of a single solid piece of metal (thus as strong as you can make them) bend and can even break in combat, joints result in the same force being applied to a much smaller piece of metal, expecting it to withstand this force is unreasonable. You can't even rely on low impact blade techniques (like the japanese created to compensate for brittle swords) since these rely on a long smooth rigid cutting edge this cutting edge is weak and has gaps which will snag.

As a whip it is a clumsy fragile chain whip.

Keeping the edge aligned is largely impossible, the only way to do so would increase the number of parts immensely which just creates more places it can fail. So you are only hitting the enemy with the edge accidentally. So really it is a flail, an unweighted flail. A segmented weapon would be comparable to a chain whip or flail both of which rely on a mass at the end to generate force, since there is no leverage, a whip sword does not have this, the whole thing can't weight more than 3-4 lbs(assuming two hands) so it is more like striking with a loose light chain by itself (albeit one with some sharp edges), which is not an effective weapon. And again it has to be full of mechanical parts to retract so there are a lot of failure points. Urami are strong enough to use becasue they are one solid piece with a continuous cutting edge (so it can't get stuck), and even then they are very unwieldy and not very effective as weapons.


Personally, the idea of judging a tool by the idea that "no one will know how to use it" is a bit unjustified. After all, many new tools are being made today, and the company that made them dont seem to think "oh, this is something that no one knows how to use, we shouldnt make this". If that was the case, people would never have to learn how to operate a new machine, or be tought how to use a new type of gun. On top of that, can you imagine how easy it would be to throw someone off-guard with a weapon/tool like a transforming sword-whip? Think of it this way:

You: has the sword Robber: has a knife, coming towards you You: swings your sword and releases the whip function, striking his legs while being at a safe distance away from his range-of-attack, immobilizing the robber

Robber had no clue that your sword could do that, and couldnt reach you before you could reach him. Or:

Robber: steals your wallet and turns to run You: before he could get out of range, swings the sword and whips him in the legs

He thought he could get away from you, but you got him in the legs first. A shock&awe type deal. Cause it looked like an ordinary sword/machette. Another use:

You: walking in the woods, carrying your sword. Too many thorned brances or bushes in the way? Step back and whip yourself a clearing

The whole "no one will be able to learn how to use it" is completely pointless to think about. Because practice and training is what teaches people how to use something new. Also i wouldnt expect someone to need anything more than a 5-6 foot long whipblade for typical use.

Now, in terms of construction, i believe that there are multiple ways this could be done, however i believe the most effective would use some kind of pressure-catch system. By that i mean it would make sense to have a mechanism that sticks into each section of the sword blade when retracted to its sword mode, as well as a multi-cable wiresystem, to keep the blades aligned, And incapable to twisting beyond retractability. A set of metal cables also seems like the best option.

Additionally, i think a torsion-spring powered cable spool retraction mech would be a good idea, as well as a catching wheel (much like what are used on some flatbed trailer straps) that will keep the blade cables held firmly to keep the sword blade from separating in battle, and a trigger that will release the toothed catching wheel when pulled.

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    $\begingroup$ Welcome to Worldbuilding! We're glad you could join us! When you have a moment, please click here to learn more about our culture and take our tour. This really isn't an answer, but rather a comment on someone else's answer. Can you edit your post to justify the weapon's feasibility? $\endgroup$
    – JBH
    Jun 20, 2019 at 18:57

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