An entrenching tool, E-tool, or trenching tool is a collapsible spade used by military forces for a variety of military purposes. Survivalists, campers, hikers and other outdoors groups have found it to be indispensable in field use. Modern entrenching tools are usually collapsible and made using steel, aluminum, or other light metals.
Entrenching tools go back at least to the times of the Roman Legion. Julius Caesar, as well as other ancient writers, documented the use of spades and other digging implements as important tools of war. The Roman Legion when on the march would dig a ditch and rampart around their camps every night where established camps were not available.
Siege tactics throughout history required the digging of fortifications and often mining of walls was attempted, where saps were dug to a wall’s foundation, and collapsing the wall was attempted.
In more modern times the siege tactics of the Napoleonic Wars used spades and pickaxes as entrenching tools to dig trenches towards the walls of the fortifications being besieged, to allow men and munitions to get close enough to fire cannons at the walls to open a breach. Being too long and heavy to be transported by individual soldiers, entrenching shovels and spades were normally carried in the supply carts (logistics train) of a military column; only pioneer or engineer troops typically carried spades or shovels as part of their individual equipment. This frequently led to situations in which the infantry did not have access to entrenching equipment when it was needed. As one U.S. army infantry officer noted, "the intrenching [sic] tools of an army rarely get up to the front until the exigency for their use has passed."
In 1870, the U.S. Army introduced the trowel or spade bayonet, intended for individual soldiers as both a weapon and an entrenching tool. This was followed by the development of separate trowel and spade tools, small one-hand implements that could be carried as part of a soldier's individual equipment. While the entrenching trowel or spade gradually gave way in the U.S. and other modern armies to larger, heavier, and more effective entrenching tools, the concept of supplying each infantry soldier with a means of digging his own entrenchments or breastworks continued as a tactical doctrine.
During the 20th century, the ancestor of the modern entrenching tool appeared in the form of the handled entrenching shovel or spade, designed to be used with both hands, yet more compact than traditional, full-sized engineer shovels or spades. These tools became extremely important with the introduction of trench warfare. Entrenching tools designed for the individual infantryman soon appeared with short straight handles, T-handles, D-handles, and other designs. The British entrenching tool of this period was a two part design, with a metal head and a wooden handle, the metal head consisted of an adze/spade blade and a pick spike, used alone the head could be used as a spade with the pick spike serving as a handle. Between the blade and the spike was a ring into which the handle could be inserted at right angles to the head, with the handle inserted the tool could be used as a pick mattock. Besides being used for digging defensive fighting positions, entrenching tools were used for digging latrines and graves.
During World War I, the entrenching spade was also pressed into service as a melee weapon. In the close confines of a trench, rifles and fixed bayonets were often too long for effective use, and entrenching tools were often used as auxiliary arms for close-quarter fighting. From 1915, soldiers on both sides routinely sharpened the edges of entrenching shovels for use as weapons.
After World War I, entrenching tools were again redesigned to be more compact and lighter in weight. Folding designs became increasingly popular, usually incorporating a fixed handle with a folding shovel head, and sometimes encompassing a pick into the design. Like all individual entrenching tools, they were designed to be easily carried as part of an infantry soldier's standard pack equipment.
The British 1937 Pattern web equipment added a bayonet lug to their entrenching tool, allowing the spike bayonet to be mounted on the end and converting the tool into a mine prodder.
The United States Army folding spade, or entrenching tool, has evolved from a single fold spade with a straight handle, to a tri-fold design with a modified “D” handle design with all steel construction, to a similar light weight plastic and steel tri-fold design adopted by NATO as the standard issue entrenching tool. Other folding variants have also been issued. The latest light weight plastic tri-fold design is thirty percent lighter than the all-steel tri-fold was: 1.5 pounds (0.68 kg) instead of 2.25 pounds (1.02 kg).
Entrenching tools, if strongly built, can also be used as ancillary weapons. Some entrenching tools can be even sharpened on one or both sides of the blade to be used as cutting tools or weapons; in fact, when used as such, the tool's sharp, thick edges are strong enough to cut through flesh and bone. During the Second World War, entrenchment tools were used in close quarters combat between German and Soviet forces, notably in the brutal hand-to-hand fighting during the Battle of Stalingrad. Soviet Spetsnaz units were well trained in the use of the standard short-handled Russian entrenching shovel ("saperka") as a weapon; by the nature of their missions, such tools were only rarely used for digging or entrenching positions. Modern commando forces, too, are trained to fight with entrenchment tools.
Many millions of surplus entrenching tools have made their way into the hands of civilians. They are commonly used for camping, gardening and by war re-enactment groups. Some people collect the older issue entrenching tools as military memorabilia.