Sapper

A sapper, also called pioneer or combat engineer, is a combatant or soldier who performs a variety of military engineering duties such as breaching, demolitions, bridge-building, laying or clearing minefields, field defenses as well as building, road and airfield construction and repair. They are also trained to serve as infantry personnel in defensive and offensive operations. A sapper's duties are devoted to tasks involving facilitating movement, defence and survival of allied forces and impeding those of enemies.

The term "sapper" is used in the British Army and Commonwealth nations, Polish Army and the U.S. military. The phrase "sapper" comes from the French saper (to undermine, to dig under a wall or building to cause its collapse).

A sapper, in the sense first used by the French military, was one who excavated trenches under defensive musket or artillery fire to advance a besieging army's position in relation to the works of an attacked fortification, which was referred to as sapping the enemy fortifications.

Saps were excavated by brigades of trained sappers or instructed troops. When an army was defending a fortress with cannon, they had an obvious height and therefore range advantage over the attacker's guns. The attacking army's artillery had to be brought forward, under fire, so as to facilitate effective counter-battery fire.

This was achieved by digging what the French termed a sappe (derived from the archaic French word for spade). Using techniques developed and perfected by Vauban, the sappers began the trench at such an angle so as to avoid enemy fire enfilading the sappe. As they pressed forward, a position was prepared from which cannon could suppress the defenders on the bastions. The sappers would then change the course of their trench, zig-zagging toward the fortress wall.

Each leg brought the attacker's artillery closer until the besieged cannon would be sufficiently suppressed for the attackers to breach the walls. Broadly speaking, sappers were originally experts at demolishing or otherwise overcoming or bypassing fortification systems.

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