As they are usually the smaller in number an appreciation of force concentration is especially important to guerrilla forces, who find it prudent initially to avoid confrontations with any large concentrations of government/occupying forces. However, through the use of small attacks, shows of strength, atrocities etc. in out of the way areas, they may be able to lure their opponents into spreading themselves out into isolated outposts, linked by convoys and patrols, in order to control territory. The guerrilla forces may then attempt to use force concentrations of their own; using unpredictable and unexpected concentrations of their forces, to destroy individual patrols, convoys and outposts. In this way they can hope to defeat their enemy in detail. Regular forces, in turn, may act in order to invite such attacks by concentrations of enemy guerrillas, in order to bring an otherwise elusive enemy to battle, relying on its own superior training and firepower to win such battles. This was successfully practiced by the French during the First Indochina War at the Battle of Nà Sản, but a subsequent attempt to replicate this at Dien Bien Phu led to decisive defeat. During World War I the Central Powers became increasingly unable to meet the Allied Powers in terms of outright number of fighter aircraft. To overcome this shortcoming rather than deploying their fighters uniformly along the fronts, the Germans concentrated their fighters into large mobile Jagdgeschwader formations, the most famous of which was Manfred von Richthofen's Flying Circus, that could be moved rapidly and unexpectedly to different points along the front. This allowed them to create a "local superiority" in numbers, that could achieve air supremacy in a local area in support of ground operations or just to destroy Allied fighters in the overall strategy of attrition. Similarly the Second World War Big Wing was one tactic that was evolved to cause maximum damage to the enemy with the minimum of casualties. Modern armour warfare doctrine was developed and established during the run up to World War II. A fundamental key to conventional Warfare is the concentration of force at a particular point (the [der] Schwerpunkt). Concentration of force increases the chance of victory in a particular engagement. Correctly chosen and exploited, victory in a given engagement or a chain of small engagements is often sufficient to win the battle. The Nazi defence of France in 1944 could have followed one of the two models offered in the hypothetical example. The first was to distribute the available forces along the Atlantic Wall and throw the invading Allies back into the sea where and when they landed.