Realism of throwing knives or daggers

Question

It lots of fictional settings and worlds, 'rogues' and other skilled martial fighters are constantly throwing knives and daggers at people. Furthermore, assassins/rogues are often pictured as having a ridiculous amount of knives on their bodies and it's a trope that they never run out ("you can never have too many knives").

Questions:

• How effective of a weapon is a thrown knife in a realistic setting (thrown by a "peak human")?
• Historically, were there fighters (not jesters or clowns) which took the time to master throwing a knife?
• Does throwing a knife in a fight make tactical sense?

Answer 1

Having thrown knives myself as a (casual) hobby when I was younger I can tell you that it doesn't take that long to gain both power and accuracy with well balanced knives. Give it a few months of everyday practice and you can hit a one inch target at a good few meters distance with a 90% success rate. Well balanced in this context means that the handle and blade weigh the same, so that the knife balances where the two meet.

The really tricky part though is judging the distance. How many times is the knife going to go end over end in the travel from hand to target? If holding the blade when throwing you need (N + 0.5) rotations. If holding the handle just N. But the number of rotations depends on the knife, both the weight and the length, and that just takes practice to learn the feel of that particular knife. To give some real-word examples, a small 4 inch (blade + handle) throwing knife might do 3.5 rotations over a ~3 meter distance, but a 12 inch knife may only do 1.5

In fact there is only about a 45 degree arc during the rotation where the knife will actually penetrate the target at all, and the closer to perpendicular the better. Anything outside of this angle range and you are hitting either handle first or flat. But getting that right every time is very hard if you are not throwing a known knife from a known distance. When we used to practice we threw from marks on the floor that we had worked out through trial and error (lots of error!) and always used well balanced knives.

So perhaps the real mark of an expert is in how quickly they can judge the characteristics of a new knife, and also how well they can spot a distance. Only a genius could pick up a knife for the first time and get a penetrating hit from an arbitrary distance though.

In the real world, the utility of throwing knives is therefore slightly questionable in my opinion, as the distance to your opponent would be extremely hard to judge in a real fight. As a distraction technique I can see it having some use, or perhaps even as a ranged stealth attack with time to prepare a throw, but I can't see it being favoured as a primary means of attack where there are better options available.

Answer 2

Keep in mind that through most of human history knives were extraordinarily common tools. Every soldier, workman, hunter, field worker, tradesman, shepherd, shopkeeper, etc. carried a knife as a practical matter, because there was always something to be cut, shaved, sized, sliced or pried open. Learning to throw a knife was a pastime (e.g., mumblety-peg) as much as anything else, and like any pastime there were always those who took it to extremes. In that sense, it doesn't matter whether it was an effective attack; it was something that could be done with something ready to hand, like throwing a rock or a tree branch.

Most soldiers in the pre-modern world carried some small thrown weapon with them. The ancient Israelites apparently had a fondness for slings; Roman legionaries carried a pair of javelins; I'm sure I could find others. These weapons weren't meant to inflict heavy casualties on an enemy, but to slow the enemy down and disrupt their ranks. Knives could be used for that in a pinch, I suppose, but I don't know of any military that used them that way. Possibly that's because a knife constituted more of an investment for a soldier than a wooden javelin or a sling-stone, and was necessary for many common daily tasks; soldiers would have been loathe to just toss them. But thrown knives may have been used in more covert operations, where silence and surprise are important.

A thrown knife doesn't have to be lethal in its own right. The shock and surprise of suddenly finding an eight inch piece of metal embedded in your shoulder — and the subsequent need to pull it out before you can take effective action — would give an attacker an opportunity to close distance and attack with another weapon. There is a value to the skill in certain types of combat.

Answer 3

Historically throwing knives have been used mainly as a distracting technique, rather than an actual attack.

They were used by what we commonly refer to as ninjas for example, and if I am correct they would be coated in feces or poison. Mostly these would be thrown when retreating, to distract the enemy and create an opening. And give them a nasty infection with some luck. They could also be used as a distraction to create an opening to attack.

As for actual (main) attacks, they are fairly ineffective. You will need a fairly good stance to launch a knife with any precision. It will hardly ever penetrate any armour, and we'll balanced ones are often too expensive to make. Using darts for example would be more effective as they penetrate better, and can be launched in more awkward stances.

Especially when knives or throwing knives are used as a main weapon there are a lot of weaknesses. Which is why rogues are portrayed as sneaky or agile. Standing still, or letting your enemy swing at you will be instantly lethal. This amount of (inefficient) skill is unlikely to be trained and used by anyone who is not an extreme expert.

Answer 4

Throwing knives, shuriken and other implements of the sort can be useful, but not as your main weapon. They can be thrown at an enemy to create an opening, because it will likely provoke a reaction, allowing the user to close in and attack with their main weapon.

While it may be technically possible to achieve lethal hits with them, such as hitting eyes or throat with the blade end on a good throw, this requires extreme accuracy, enough power, no successful defence on the opponents side on body parts that are usually well defended, you have to hit with the right part of the weapon and it will not penetrate armour or even thick clothing. This isn't reliable enough to use as a primary means of attack.

Answer 5

As far as I know, throwing knives were never issued by any army or used on any sort of scale, unlike stones, hammers, axes, 'darts' and a variety of other missile weapons. Cleary they lack the range and lethality of any 'proper' thrown weapon.

(Added explanation in response to question: it's a simple matter of kinetics. A manually-thrown weapon moves at the speed of your hand. A knife does not move faster than a javelin, dart or heavier projectile, but lacks their mass therefore hits with less kinetic energy and momentum. In theory a 200g knife could have a greater range than a 1 kg javelin, but in practice this is not the case because of the knife's spinning dynamic and need to hit point-first)

(Edit: shuriken are not lethal weapons, and in any case can hardly be considered to be 'knives')

In modern military situations they are a weapon of last resort, and while knife throwing is sometimes taught, it's hard to see how it would be used .

I haven't come across any accounts of one being successful in European warfare, but having wondered about posing this exact about this myself (thanks to Hollywood and D&D) I will be very interested to see if any cases are cited.

Answer 6

It might make sense as an attack of opportunity, not as a large scale mean of attack.

Why?

• you can't carry that many knives on yourself
• every knife you throw becomes a knife you are giving to your enemy
• your arm alone can't deliver that much momentum, bows or slingshots work better at that and allow you to have a greater range

Answer 7

It is a cultural throwback/tradition with little practical use.

Traditionally it was considered dishonorable to attack/kill an unarmed person but perfectly respectable to kill an armed person.

This infuriated the local assassin's guild since by not carring a weapon made you unkillable.

The get-around was to first forcibly give your target a weapon and then proceed to kill them. Originally you had to be sneaky about it: Spend weeks earning their trust and then give them a present of a small, ornately-guilded box. The moment they open the box to reveal the dagger inside they are technically armed and then you stab them in the face.

One day Sneaky McShankFace got the bright idea to simply throw the dagger into the victim. Once the dagger was embedded on their person they are fair game. This made the whole game much simpler.

The law was later changed to prevent this getaround. But by then it had become a tradition in the guild and stuck around because of that. The rest is history.

Answer 8

+1 to the current top voted answer by dave. I want to add to it.

To what he writes, I can only add that my experience matches his. Distance matters, hitting flat or handle first is common while you're training, but hitting well and hard takes not that much experience. I've managed to lodge throwing knives into wood so deep that I had trouble pulling them out. You can definitely bury a throwing knife in a person to the hilt.

The question he doesn't answer:

Yes, you can carry a good amount of throwing knives with you. Unlike a cutting knife, you don't need the handle except for balance, so it can be thin or even missing, meaning they don't take up much space:

weight is more of an issue, because the knife cannot be too light or it won't have enough power to penetrate anything. I remember about 200g being a recommended weight for close-distance throwing, 250 and up if you want to throw longer distances.

Ten knives would be about 2kg plus holster, and easily fit on a belt. That's quite manageable. I've never actually carried that many knives on my person, but I've carried similar amounts of stuff on my belt in medieval fairs and re-enactment and the main problem was with stuff swinging around, not the weight of it.

Answer 9

Yes, throughout central Africa they had multi-bladed throwing knives like the kpinga, these were used in war. Other cultures had similar knives.

Considering that they didn't wear a lot of armour these could do a lot of damage and were difficult to dislodge in a hurry if you got struck.

Very nasty weapons. Not the primary weapon of course which was a spear but dangerous from 30 feet and more, and if a whole bunch of them were flying at once it could create havoc.

Your basic well balanced throwing knife has quite a few drawbacks in comparison. Primarily that you need to judge the rotation and distance which only comes from practice with identical knives. This sort it doesn't matter where in it's rotation it hits a person. It's not a precision, finesse, stealth attack weapon, it's a nasty, scary, hit you anywhere and see if you bleed out weapon.

Answer 10

Another way to think about it: compare a knife to a baseball. In baseball, getting hit by a pitch HURTS. It can often break bones. Certainly, players can be injured to a point that they are removed from play with a replacement runner.

If a knife was thrown with the same force by a "peak human", assuming the sharpened end landed first, you would expect even more harm. If the knife landed in a good spot, you could easily disable or kill a target.