The Blood Groove

Update – 9 June 2020 – a commenter has pointed out that the ‘Marine Corps Dictionary’ that I originally referenced may not have been a ‘thing’ and that the USMC has never taught this. I have found references to individual U.S. Marines who have espoused this, but I have edited the below with a more definitive military claim from the British Army… Edited post follows;

A straightforward piece of mythology this time. If you’ve ever looked at commercially available swords or knives on the internet (and who wouldn’t) you’ll see such marketing buzzwords as “battle ready” and “blood groove”. Sometimes they are recent inventions designed from the ground up to make the product seem more attractive – in this case, more warlike and gruesome. But “blood groove”, though totally bogus, has a much older usage within, and with relation to, Western armies.

The misconception is widespread all over the web and in real life, as applied to any edged weapon with an obvious channel or gutter running the length of the blade. Or part of it. Even the British Army training pamphlet for the SA80 rifle (quoted here), and the Ministry of Defence website at one time, makes this claim;

“These recesses along the blade reduce any suction effect and enable a clean withdrawal from the body.”

Other versions state that it’s to allow the blood to flow out, which I suppose is the same argument. You might even hear that the idea is to reduce the noise of the blade as it’s withdrawn! As sites like Sword Forum International have pointed out over the years, the argument is not only inaccurate in technical and historical terms (see below) but also with respect to physics and biology. The surface area of the blade is too little, and the friction between blood-slick wound and smooth blade too low for any real sticking to occur. When a blade does resist a simple withdrawal movement, a fuller, as the “blood groove” ought to be known, will do precious little to help. A smart twist of the rifle accomplishes far more, and has been taught for as long as armies have used sword or knife bayonets rather than the older thin socket type (which often also bore narrow fullers along two of their sides), or the spike bayonet of some more modern weapons (which have their own fluting in place of grooves).

In reality, the blood groove is nothing of the sort, and the correct answer has been out there online for at least ten years now. Given that the famous Roman gladius (primarily used for thrusting) never featured such a channel, and the early medieval sword (designed for slashing) always did, it’s clear that it served a different function. The answer involves straightforward physics – by removing metal from the middle of a blade you reduce its weight without compromising its strength too greatly. The same approach is used in engineering in the shape of the I-beam. With the later bayonets, there is a secondary function in that the square-cut groove also makes for a very secure fit in the sheath so that the weapon can’t be lost or rattle around, and moisture has a harder time penetrating.

A range of (sword) blade cross-sections, some with fullers.
Public Domain image from wikipedia – see for more information

Whilst it’s easy to understand civilians getting the wrong end of the stick – they don’t tend to have to stab living things with edged weapons – surely the armed forces must know what they’re talking about? Well, not always. The use of swords in war was last seen amongst the first cavalry units to arrive at the Western Front in the First World War, before it was realised just how anachronistic cavalry had become. They typically would use long thrusting swords + the momentum of their mounts to kill enemy soldiers – any suction on the withdrawal wouldn’t even have been a factor due to this assistance in momentum. In fact any trooper studying the design of his weapon might well realise that the “blood groove” was actually helping to allow a stiff light blade that wouldn’t flex on impact.

Punch, Vol 153, 1917

The origin of this myth lies instead with the infantry – specifically in bayonet fighting, or since this rarely occurred even in the 19th century, bayonet drill. By the end of the 19th century (arguably earlier), this savage piece of training was primarily intended to instil a warrior spirit, and to override the natural hesitation of a volunteer soldier to kill face-to-face. Its main practical purpose was the execution of wounded enemy soldiers following a battle. It remains a piece of military tradition that helps to maintain continuity and a sense of tradition. It’s a source of pride for many armies today, whether in rare instances of actual combat, or on the parade ground. The order to fix bayonets alone is a way to focus the mind and prepare for conventional engagement, close quarter battle with automatic weapons and grenades, or maybe even showing the enemy a bit of cold steel. Soldiers – army or marine – are closer to the enemy than any member of the armed forces, but even they have become somewhat removed from the act of killing by the range, accuracy, and sheer suppressive weight of fire that modern small-arms can achieve. Fixing bayonets makes it personal again, even if it never comes down to true hand-to-hand fighting.

From many anecdotal accounts in print, oral history and online, it’s clear that drill sergeants throughout the 20th century made reference to the “blood groove” as a graphic way of interpreting the violence of combat and the need for well-learned drills to survive such an encounter and do brutal harm to the enemy. There would be no notion of stabbing one’s enemy and leaving it at that – you had to thrust, twist, and withdraw. The twist, explained as being another way to overcome the mythical suction, would be of real use, dislodging a bayonet stuck on or in bone or other tough bodily substances. It also makes more sense as a sequence of movements if there is a bridge between thrust and withdraw – like a combination of punches in boxing or a forehand/backhand in tennis. Talking about the blood groove fixes that step, and indeed the whole drill, in the mind – the perfect Derren Brown-style memory aid to assist muscle memory. It also psychs up a recruit in the absence of a real enemy or fellow soldier (sandbags being the preferred practice target for actual contact practice).

This meme was probably reinforced by real life experience (read Confirmation Bias) when a blade happened to stick briefly in bone, cartilege, or even the ground below the body. I suspect that it then passed from the military sphere to the civilian one during and after major conflicts – certainly the Second World War, probably the First, and quite possibly earlier than that, being reinforced each time soldiers came home on leave or at the end of a campaign. It’s happening again; I’ve heard it from serving and retired soldiers first-hand, and the exposure they’re getting in the media is another factor – a sergeant with the Royal Anglians in Ross Kemp’s recent fly-on-the-sangar-wall documentary trotted out the myth to Kemp, and presumably, to his recruits. In online discussion after the programme, some refused to believe that it wasn’t true, showing how well entrenched the idea is.

I think this is the origin of this myth – a tool to convey the visceral and aggressive nature of hand-to-hand combat to two main audiences. Firstly, to recruits already familiar with the concept of killing another man for a just cause: the idea further steels him for battle and instils a measure of blood-lust. Arguably its about conditioning a man to kill another – paper rifle targets don’t have the same effect. To civilians, it’s maintained so that we can explore this same dark side of human experience – one we’ll never know. Like watching a horror film – to be both excited and repulsed. I think both are valid things to do, but as with all myths, I’d rather people were told the legend, closely followed by the truth of the matter.

One caveat to finish with – it’s possible given the long history of the myth that at some stage, weapon designers or procurement officers really did belief that was the purpose of the groove, and continued to incorporate it for this reason. I’d like to see some evidence of this however. Regardless, the actual function served by the feature remained that outlined here.


35 thoughts on “The Blood Groove

    1. Okay, I know what a fuller is and I know what its purpose is. And I’m also a Marine, now in all fairness you “might” have gotten the comment “A groove in a fighting knife or sword to allow for blood to flow from a wound so that the blade can be removedeasier (a significant concern in close combat).”
      From a Marine, but to say it’s what the Marine Corps says is BS my friend, I trained and taught 250 MARINES each month, Sentry Removal, using knife fighting techniques.
      And have never heard any of my trainers or any other Marine speak or make that comment. My point is your wrong to claim THE MARINE CORPS as a whole makes or made this commitment

      1. Thanks for the comment. To be fair though, I didn’t say I got it from a Marine, and I didn’t say that the Marine Corps as a whole claims this. I said that I got it from a post on that referenced the ‘Marine Corps Dictionary’. The link is long dead (I wrote this twelve years ago), so I can’t verify the source, but as I can’t now find any reference to such a dictionary, I am prepared to believe that it’s incorrect.

  1. Hi. Thanks for the interesting read regarding the military mythology of the reasoning for the term blood groove. I would like to help with your understanding however since you have come to a couple of invalid conclusions. First of all, this channel is not properly called a “fuller”. While you may find many modern blade smiths who use this term for the gutter, you will not find it in old blacksmithing texts, nor will you hear it pass the lips of old time smiths. It is the tool used to make the groove which is called a fuller. This tool is used for many projects which have nothing to do with blades. A fuller is a shaped tool which presses into hot steel to make it “fuller”. You know? MORE FULL. When a lady exits a hair salon after having her hair worked with a flat iron, do you say “her hair has a flat iron”? Or do you say “it has been flat ironed”? One reason that modern blade smiths may call the groove a fuller is that they have no apprentice training under an old timer and have never read any old texts on the subject. I have. Old timers will state that a blade has been “fullered”. This does not make the groove a fuller, in the same way that flat ironing hair does not make the ironed hair a flat iron. This is largely an English phenomenon as blades smiths speaking other languages do not call the groove and tool by the same name. It is innocent ignorance, and nothing more.
    Now to the term “blood groove”. This is a simple thing if you have any experience with animal slaughter. I have slaughtered scores of animals, large and small with a knife. You are correct that the groove serves no purpose in retracting the blade or reducing suction. It’s primary purpose is of course structure. Reduce the amount of weight and keep the strength. Though of course for many modern smiths who make wall hangers the purpose is demonstration of craftsmanship.
    How then did this become called a blood groove? If you use a fullered blade when slaughtering livestock (kosher kill) it will become obvious. Blood from the kill will pool in the groove. This requires no scientific proof or historical documentation. Repeated observation of slaughter will provide all the evidence required to make this deduction. Long before the introduction of homeland and Costco, in fact for many thousands of years, ordinary every day people frequently were involved in bloodletting. Dinner time involved making a bloody kill, not a trip to the grocer. Modern diners are far removed from the circumstances which helped coin these terms such as blood groove or fullered blade. It’s no surprise then that they come to silly conclusions about them.

    1. An interesting point, but ‘fuller’ remains a correct term for both tool and groove, and I’ll explain why in a new post when I have a moment.

  2. I am not bullheaded, and on the contrary eager to know the truth in all matters with the exception of a “truth” that demonstrates that I am not quite as handsome as I believe I am. However, your explanation should include a reference to literature that predates the modern re-emergence of bladesmithing on the heals of the ever popular medieval fair, preferably something 19th century or before. I defy anyone to produce such literature

    1. I don’t normally like to invoke the oft ill-used phrase ‘absence of evidence does not equal evidence of absence’, but in this case it applies, as I’ve posted evidence in my follow-up post that the word was in fact in use well prior to 1930.

  3. One of the last people (if not ‘the last’) person to receive the title, ‘Master Armourer’ by none other than the Queen herself, is a guy called Chris Dobson. He was awarded the title due to his work of reproducing accurate representations of ancient weapons for various museums in the UK. He uses the terms, ‘fullering’, ‘fullered’ and ‘fuller’ to describe the act, the end result, and what the resulting channel in the blade is.

  4. 20 years plus ago I was in a Early Medieval re-enactment society (‘Dark Ages’), basically pre(widespread) internet- early 90’s. My ‘thegn and I were talking about this – he said ‘every fantasy novel seems to have a bit where the hero realises he can stab with his [broad]sword and the fuller is ideal for channelling the blood.

    It was called a fuller then, before internet communications, and the same myth was around. It was rubbish back then. Swords are used for slashing.

  5. Am just curious, is there any significant difference/pros & cons between swords with a fuller and swords without (say, a hexagonal cross-sectioned blade)? I noticed that most Viking swords tend not to have fullers, and since the main point of having a groove is to lighten the weight of the blade, does this mean Viking swords are, in general, heavier as compared to fullered blades?
    I guess my question in short is, is having a fuller more of a cultural thing or more of a structural consideration?

    1. Viking and other Migration Era/early Medieval swords do indeed typically have fullers; they are often very broad though, so perhaps that is what’s throwing you off? In answer to your question, I’d say it’s primarily structural, and partly cultural/fashionable. Some form of fuller is required for certain blade forms; how this is rendered is where there’s room for cultural expression e.g. three narrow fullers vs. one broad one.

    2. Iron and steel were expensive. Using as little as possible was desirable. Then, the cross-section increased strength of imperfectly produced materials. As steel improved and became more common, the fuller went away.

      Also, early swords had very tip-heavy balance. The combination of a fuller and pommel set the center of gravity further back toward the hilt and enabled better and easier use.

      Quite a few early swords were intended more as status symbols than weapons—behold, I have enough iron to make an entire weapon of it! Rather than putting a point on a stick.

  6. A fixed bayonet in combat as a weapon for frontline troops is seemingly better suited to the American Civil War than modern combat, who depend more upon firepower than frontal assaults. Nonetheless, in close combat, when all hell has broken loose and the frontline is no longer recognizable, wherein enemy soldiers have mingled with friendlies, a blade attached to the end of one’s rifle adds a depth of offensive and defensive ability like nothing else.

    Yes, the bayonet is a weapon of the past. But like the F-4 Phantom in Vietnam, unfortunately designed without guns, because missiles were supposed to be so much more effective, we find the older weapon has still a major role to play in modern combat.

  7. All the articles i have read yet seem to imply that medical experience means nothing. Many of us have heard that “if stabbed, leave the knife in, it acts as a cork.” if there is a blood groove, the cork has a hole

    1. If you are leaving your knife, bayonet, or sword in the victim’s body, you’re doing it wrong. The amount of blood that could flow out and along a fuller in the short space of time in which the blade is in the body would be negligible. It would be interesting to see that quantified with experimental work, but it’s a moot point.

      1. I know, this is an old post, but the internet is timeless, and it took me three years to find this article…

        I am an Army medic, (about to retire ), so medically speaking, the purpose of leaving a penetrating object in is to occlude the blood vessels and reduce the amount of bleeding, hence it acts like a cork. This concept absolutely applies in cases of accidental penetrating trauma where first responders are trying to stabalize the casualty until they can be moved to a higher level of care, such as an operating room. We always say, leave it in, let the surgeons take it out.
        As for combat, which is a completely different scenario, yes, pull it out, and then stick it back in, and then pull it out, and then stick it back in again, repeat process until the task is done.

        We have never talked about blood grooves in trauma management of penetrating objects, (I am not denying that it is talked about, but it has never been a part of our curriculum, or a topic of discussion in our training).

      2. Many thanks for your insight and don’t worry about being late; these articles are meant for the long-term, and as I’m a Web 1.0 relic without the time to make them more social media-friendly, only the dedicated are likely to find them πŸ™‚

  8. Playing Squad Leader a highly researched game they had a few Calvery Charges Russian Front where Sabers did get used in scenarios.
    Also US Marines in WWII on one of first Island landing had a successful Bayonet Charge over Concrete Causway.
    Read current reports that Special forces find Bayonets good for prisoner gaurding

  9. I did not read all of your document. However, I have personally stabbed people and have also been stabbed. There is a difference in feel from the blood groved knife compared to a non-groved knife. The twisting of the rifle is just to inflict more harm and a more open wound. I find it funny that people who have not actually done harm to another individual (my case self defense) do these reports. If you have held and actually stabbed people with either style of blade you would feel the difference. Point in case, I had a sewing needle stabbed into my toe.. it stuck to a point of pulling my foot and leg with it in a slow pull.. I had to pull it hard and fast to remove it. Just saying, that’s my personal and painful experience.

    1. Just because it feels different doesn’t mean that there’s a suction effect. Also, what I’m trying to tell people is that the actual people who made and make these weapons *do not put the groove in to make the blade easier to withdraw*. The clear design intent is to lighten the blade. Perhaps you should read the whole thing if you’re prepared to put the time in to comment.

  10. Regardless of the finite details of the discussion, I appreciated the articles author taking the time to write the story, it was truly informative. Obviously, after reading all the responses, there are still questions since none of us exceed 100 years old to actually know. As an engineer, I can appreciate trying to make the instrument lighter, especially when these ancient battles lasted hours and hours long. To me that makes the most sense. We manufacture modern gun barrels with flutes to reduce weight without losing strength.

  11. Have none of you and your marines ever oiled a blade to prevent corrosion? Iv never been a 15th century warlord, but the most practical use of the groove is a drip line for the oils. The minimalist soldier even cleans, oils, or may polish the sword every day. 1 square of of cloth. Drip oils on both sides of blade and let the oil gravitate down the groove effortlessly throughout entire length of the blade…. Take that square and 1 careful, slow, delicate sweep with the edge downward facing away from palm of hand unless it’s a double edge. In that case you might want to make 2 oil applications. Sweep thumb and finger down the blade twice with majority of pressure pushing into the grove leaving the coating at the edge thicker. Those guys did this every day in a matter of seconds. With a blood groove u don’t have to drench more than a square inch of cloth in oils, u use less oil, and it’s done in a matter of seconds. In the heat of battle you should worry about the edge getting crammed in bone rather than getting caught in suction
    of your victims wound… Let’s be realistic. Even the most expensive swords bothe now and then used iron. Oil your wall mounted history art using the blood grove. Someone make this sword maintenance tutorial viral please. The idiocy is killing me. It also saves low supply areas prescious iron, and it’s lowers weight without losing durability for longer sword necessities. Oil the damn thing or throw it in the trash. Otherwise it will lose its polish and make u look ridiculous

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