An Important element in the Viet Cong's guerrilla warfare was the widespread use of booby traps. Ingeniously contrived from readily available materials - sometimes from captured or recovered mines and ammunition - these unseen weapons were often made by old men and women and children. So effective were they that in some areas they were said to account for up to 50 per cent of allied casualties. Australian soldiers on patrol were trained to look for anything that might indicate the presence of a hidden mine or booby trap near by disturbed foliage, an unnatural arrailgement of sticks or stones, and any wires, rope, string or vines that could spring a trap or trigger an explosion. They were ... warned against relaxing their vigilance; unwariness when approaching their own base or taking advantage of some shade trees for a rest could result in sudden death or injury.