When Russia launched its war against Ukraine on February 24, it did so with missiles and helicopters. Not far beyond, stretching for miles, was the slower work of armored vehicles. Tanks and artillery, brought to staging areas near the border for several months, entered Ukraine. With them, the war turned from an attack to an invasion, and some people in Ukraine set about building defenses against the advancing army.

In Lviv, western Ukraine, residents have started assembling metal anti-tank barriers, Agence France-Presse reported. The shape, which resembles a child’s toy jack made of steel I-beams, is known as the “steel hedgehog.” The earliest versions of this barrier date back to defensive fortifications built in Czechoslovakia in the 1930s. Some of these Czech fortifications may have even been turned by occupying German forces into barriers on Normandy beaches before D-Day. It is this use that gives the obstacle the name of “Czech hedgehog”, this is how the Ukrainians interviewed by AFP in Lviv described what they were creating.

A U.S. Army Engineer School correspondence course on fortifications describes steel hedgehogs as “relatively light for the obstacle effect they provide, and they are quickly installed or removed.” They are designed to turn under wheeled vehicles and puncture them or to overturn tracked vehicles. Unless they are kept under observation and covered with fire, the enemy can easily brush them aside.

The last line is key: steel beaters are a particularly minor obstacle if not actively defended, as they can be lifted, towed, or even moved, clearing a path. If, however, the row of steel hedgehogs is defended by soldiers, it can add extra protection to infantry and reduce one of the main advantages of armor.

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Tanks, as well as other heavier vehicles like armored personnel carriers, are most effective when they have freedom of movement. A turret cannon is a powerful weapon, and in open environments like plains, foot soldiers are at a huge disadvantage compared to vehicles.

Move over any type of denser terrain and tanks have less freedom of action. Trenches, fighting in forests, narrow roads through swamps, and fighting in towns aggravate the circumstances in which a tank can struggle in combat. Given the choice of fighting through a path with hedgehog obstacles or going around, tanks with a redirect ability will likely do that.

If they move forward, they might run into one of the hedgehogs. When a tank rolls over a hedgehog, the obstacle rolls under the tracks and lodges in the vehicle, lifting the tank into the air. If a tank gets stuck on such a trap, it is a sitting target until it can be towed away, and its crew would be faced with the choice of evacuating under fire or sitting down and hoping that no one with anti-tank weapons finds them.

In the years between World War I and World War II, as the military experimented with a range of tank design approaches, military engineers also moved to work on tank obstacle design. In October 1936, a popular science The illustration of the Maginot Line fortification in France showed steel rails driven vertically into the ground as an anti-tank barrier. One May 1938 popular science The story stated that the British Army had found success using coils of wire and upturned steel rails as obstacles, although this report also notes that these barriers were secured by “anti-tank guns firing armor-piercing shells” .

Once World War II broke out, the military adopted new approaches to stopping tanks and conquering battlefields. At Fort Belvoir, Virginia in 1942, popular science reported on the work of Army engineers designing new tank barriers, and Virginia National Guard tank drivers who repeatedly drove tanks into these barriers to see if they worked.

Probably drawing on this experience, a 1943 Army Engineer Field Manual describes the use of ditches, fallen logs, and poles as means of disabling tanks. ‘Abatis’, or chopping down trees on a road to prevent enemy advances, is such a durable tactic that NATO forces have released a video explaining the method, performed during a training exercise in Lithuania in 2016. In 1943, the same year, the army taught ditches and abatis, popular science included hedgehog-shaped “jacks” as one of several types of barriers used to stop tanks, alongside cement “dragon’s teeth” and pyramidal tetrahedrons.

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Steel beaters have held up as an anti-tank tool in wars partly because their strength is due to their geometry. While other barriers can be destroyed from a distance, eliminating hedgehogs requires being nearby. Even with dedicated vehicles to clear the way, the existence of a hedgehog barrier suggests that other soldiers lurk nearby with guns and anti-tank missiles, ready to kill enemies as they approach. Artillery support tanks are a sinister response to this tactical challenge, which can destroy hideouts of defenders in urban areas, and at the same time threaten the lives of any civilians still living in a neighborhood turned into a battlefield. .

It is in preparation for future urban battles that these barriers are most often built. Deployed in Ukraine, the hedgehogs created surreal images of modern warfare. One of The most striking is that of a Tesla electric car, stopped behind a line of steel beaters in Kiev.