The Claymore is perhaps the most famous mine of the latter half of the 20th century.  Making a name for itself during the Vietnam War, it was used to great effect by US forces to repel assaults and initiate ambushes. Over the years, allies and enemies took notice, and it has spawned many copies while remaining a highly effective instrument for literally shredding the opposition.

Unlike traditional land mines, which direct their explosive upward, the Claymore is what is called a “directional mine.” This means that the user points the mine by using a crude sight on top, and steadies it with twin scissor-like anchors which can be pressed into the ground, or stand free on their own. A wire is then unfurled a safe distance back to the user’s position were a detonator in the form of a clacker is squeezed to initiate the explosion.

Since the Claymore has a curved rectangular shape, once fired, plastic explosive hurls 700 steel balls out in a 60° radius. Anything exposed within a 50 yard distance is bound to become a casualty. This only increases by magnitude the closer to the detonation. The function is rather like dozens of shotguns going off at once. There is nothing like it on the battlefield.

The physical appearance of the Claymore is known throughout the world. Besides its physical shape, it is constructed of green plastic and has the famous words “FRONT TOWARD ENEMY” in raised letters, warning the user which direction to point the business end. This assures mistakes in this manner are nonexistent and that the mine will live up to its name, which comes after the Scottish Claymore sword which cut swathes through its enemies.

Before the Claymore arrived, though, a certain concept needed discovery. This began in World War II, when a Hungarian and German scientist revealed that an explosive with a heavy backing surface, like a steel plate, could direct most of its energy forward with significantly less danger behind it.  They named the discovery after themselves, the Misznay-Schardin effect, and spent the remainder of the war trying to perfect it by creating different mines, such as antitank and trench versions, which demonstrated that the effect had promise. However, none ended up in use because the war came to an end, so the theory was shelved.

That ended with the Korean War, when the Chinese launched massive human wave attacks that sometimes overran Allied positions. Conventional minefields helped, but planting them took too long and units desired something just as effective and quick. Afterward, in the United States and Canada, designs for an answer began to take shape.

Canada was the first to try the Misznay-Schardin effect with a large mine backed by Composition B that propelled steel cubes. Known as the ‘Phoenix’, it proved problematic and impractical due to its size. At nearly the same time, a similar design much smaller in size was developed in the U.S. At last, a workable directional mine had arrived.