Sapping : First World War
A tactic used on the Western Front was to dig short trenches (saps) across No Man's Land. These were dug towards the enemy trenches and enabled soldiers to move forward without exposure to fire. Several saps would be dug along a section of front-line. These were then joined together at their far ends to create a new trench. Saps were also used as listening posts. Although sapping was slow and gruelling work, especially during summer months, it was a fairly safe way to make territorial gains.