Knives have been with us for as long as when the first caveman had that eureka moment and thought of sharpening stones and animal bones to kill wild animals. From then on, countless designs and ideas sprung up designed for different purposes. They were no longer just used for killing animals but also for close-combat purposes, whenever needed— like during WWI.

Combatting in the trenches was undoubtfully difficult. The attack, counterattack, and defense were all made on foxholes dug into the ground. What’s more, opposing trenches were usually close to one another. Fighting in the trenches of WWI involved a lot of storming the enemy’s positions brutally close combat. Weapons like long bayonets fixed to rifles proved unwieldy in the narrow trench lines.

What would be the best weapon for close combat in a confined area? Knuckle bar? Knife? How about both? That’s what Henry Disston & Sons, a civilian company making tools and saws, thought when they designed the M1917 trench knife. Inspired by the French Nail knives, it has a long, triangular blade and a knuckle guard on its handle. Henry Disston & Sons were not traditional knife-makers, so the M1917 turned out to be rather flimsy, and since the blade was triangular, it could only stab but not cut.

Shortly after, these deficiencies were addressed with the improved M1918 trench knife. This version has a brass knuckle-duster grip and a double-edged blade. It could be used both for stabbing and slashing.

They still wanted to improve M1918’s durability, ease of use, security of grip, and ease of carrying, so the American Expeditionary Forces (AEF) officers and the Engineering Division of U.S. Ordnance brought Mark I Trench Knife to life. It still has the 6.75-inch double-edged steel blade, a cast-bronze knuckle-duster grip that could break a nose and prevent the knife from being taken from the user’s hand, an oversized steel scabbard, and a nasty addition: skull-cracking nut on the pommel.

During World War II, Mark I was used by army rangers, marine raiders, and airborne troops.

There was also the Hughes Trench Knife that was invented and patented by a captain in the United States National Army, Rupert Hughes. His idea was a spring-loaded, foldable knife blade attached to a handle and can be secured at the back of the hand by a leather strap, so the wearer could still grasp and hold other things. A button on the handle can be pressed to release the knife into an open and locked position. It was tested and was unfortunately found to be of no value by the board of testers.

The WWI Trench knife was a fearsome weapon of war. There is debate today over whether or not the Hague Convention bans such weapons.  The wording of the text does not specifically ban combat knives, but outlaws weapons intended to cause “unnecessary suffering,” which is pretty broad.  A combat knife with a sawtooth edge would qualify since it leaves a jagged open wound that would be hard to close(at least under battlefield conditions).  This might apply as well to triangular-shaped blades which leave a puncture wound rather than an incision-type cut that would also be hard to stitch up and close.  On the other hand, a triangular-shaped blade is superior at punching through several layers of winter clothing where a blade type knife would not.  The most simple way to know which type of blade is approved for warfare is to look at the types issued to service members today by their own governments, which do not include those with brass knuckle grips or serrated blades.  This doesn’t mean that troops can’t buy a weapon like a traditional trench knife to add to their kit, but they might want to get rid of it before getting captured by an enemy.