A reverse slope defence is a military tactic where a defending force is positioned on the slope of an elevated terrain feature such as a hill, ridge, or mountain, on the side opposite from the attacking force. This tactic hinders both the attacker's ability to observe the defender's positions as well as reducing the effectiveness of the attacker's long-range weapons such as tanks and artillery. Its advantages are negated, however, if the attacker has substantial air presence – even short of air superiority, let alone air supremacy – that enables the attacker to obtain an aerial view over the crest of the terrain feature.