The classic interpretation of X is that of German tactical and operational methodology in the first half of the Second World War that was often hailed as a new method of warfare. The word, meaning "lightning war", in its strategic means is associated with a series of quick and decisive short battles to deliver a knockout blow to an enemy state before it could fully mobilize.
The tactical meaning involves a coordinated military effort by tanks, mobilized infantry, artillery and aircraft, to create an overwhelming local superiority in combat power, to overwhelm an enemy and break through its lines. X as used by Germany had considerable psychological, or as some writers call, "terror" elements, such as the noise-making sirens on the Junkers Ju 87 dive-bombers to affect the morale of enemy forces. The devices were largely removed when the enemy became used to the noise, after the Battle of France in 1940, bombs sometimes having whistles attached instead. It is also common for writers to include psychological tactics behind the line, using Fifth columnists to spread rumors and untruths among the civil population in the theater of operations.
X?
Ans : Blitzkrieg
