What is a Trench Knife?

Mary McMahon
Mary McMahon

A trench knife is a knife which has been specially designed for close-quarters combat such as that which characterized the trench warfare of the First World War. In fact, the trench knife design originated during this conflict, and it proved so useful that militaries continued to issue trench knives long after the days of trench warfare were over. Suppliers of knives and military equipment often carry trench knives, including replicas of famous models from the First and Second World Wars.

Trench knives originated during World War I.
Trench knives originated during World War I.

The key feature of a trench knife is that it is short, allowing a solider to use it in close quarters, and also extremely sharp. The blade is classically straight, and it may be grooved with a single channel. The earliest trench knives were simply personal weapons or modified bayonet blades and swords, but military strategists quickly realized that issuing a special-purpose trench knife would be highly advisable.

In addition to having a rather wicked blade, many trench knives also have a heavy, solid pommel which can be used very effectively for punching, especially for blows to the skull. Some trench knives also have a hand guard which can theoretically double as yet another surface which can be used for punching. These “knucklebuster” trench knives sometimes have handles shaped like brass knuckles, providing a solid grip while offering hand protection to the user.

Soldiers utilized trench knives when they went over the wall into the trenches of the opposing side. The blades could be safely used in crowded and cramped trenches, and they also carried the advantage of being silent weapons. Scouts and other individuals who went over the wall first often used trench knives to remove sentries and guards so that the enemy would not be aware of the approaching attack. Silent weapons were often preferred for trench raiding missions, because they attracted no attention, reducing the risk of alerting the enemy.

In some regions, civilians are not allowed to carry trench knives. The length of the blade can become a factor, with people not being permitted to carry blades over a certain length in public. The presence of knucklebusters can also be an issue, as knuckled weapons have been specifically banned in some areas due to concerns about their use in criminal activity. In these situations, people may be allowed to display a trench knife in the home, especially if it is an artifact of military service, but they may not carry the blade in public.

Mary McMahon
Mary McMahon

Ever since she began contributing to the site several years ago, Mary has embraced the exciting challenge of being a wiseGEEK researcher and writer. Mary has a liberal arts degree from Goddard College and spends her free time reading, cooking, and exploring the great outdoors.

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Discussion Comments


@croydon - All war is ugly, although fighting in trenches was certainly pretty bad as wars go.

I remember in Slaughter-House 5 there was a character that had a custom trench knife that had spikes on the brass knuckles and several sharp blades as well.

I guess in some cases it was more about intimidation than about efficiency, since I can't imagine three blades would actually make the knife any better at killing people, it would just make it unwieldy.

I can really imagine people creating things like that though, and I wonder how many people are collecting those kinds of knives now. Some of them might have been made by the blacksmiths they used on the field, so they'd certainly be able to survive until this day.


@umbra21 - The army made trench knives are actually kind of surreal looking to me. They just look vicious and like something out of a fantasy novel, a knuckleduster attached to a knife.

I can certainly see why they wouldn't want those to be carried concealed on civilians.

I think even brass knuckles are banned in most places, just because they are too easy to take too far. They are basically made to break bones.

Add that to a sharp blade and you've got a recipe for trouble.

Of course, that's exactly why they designed them that way for people in the trenches. It was such an awful, ugly way to wage war, and this was yet another aspect of it.


I've seen pictures of a WW1 trench knife and it seems to be little more than what is known as a shank or shiv, which is a makeshift knife often constructed in prison.

And I guess that makes sense. Trench warfare was brand new to most people in that war, so they didn't really know what to expect. Once it became clear that sometimes you were going to end up in close quarters with the enemy, soldiers were going to want to have something available that could make the difference between life and death.

I understand that many of them would simply shorten their bayonets. If someone is fighting you in a trench you simply wouldn't have room to use a full length bayonet.

It was only in later years that the armies began to issue them directly.

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