German term for "fast war".
Historically, the term is generally used to refer to the campaigns of Nazi Germany in 1939 and 1940, in which motorized forces were used in large scale for the first time, and campaigns by the United States and its allies in 1944 France, 1991 Kuwait-Iraq and 2003 Iraq.
However, the basic strategy of "blitzkrieg" warfare can be applied in EU2. This takes on two very different forms, which can be used in combination or separately:
First, the "mass pillage" tactic, often used to disable the opponent's economy and thus hamper the recruitment of new forces. This is often accomplished by the use of numerous small all-cavalry units (often 3000-5000 troops per unit) which spread out rapidly, taking up stationary positions throughout large portions of enemy territory. Other forces can be used for this sort of tactic, but all-cavalry units have the advantage of being able to take up their positions very rapidly due to their higher movement speed. Slower forces of infantry and artillery are then used to supplement these and conduct sieges. Another advantage of this strategy is that since they are the first troops to arrive, the "blitzkrieg" aggressor country become the siege leader of any potential siege, unless their allies bring special leaders or the victim manages to drive them away. The main disadvantage is that such wars require much advance planning and do not conclude much faster than traditional wars.
Second, the "fortress-assault" option. This is not available until a country reaches land tech 5. Once a country has that technology, it may use infantry forces to "storm" the fortress rather than waiting for a months-long siege to conclude. The attacker often takes horrible casualties in such an assault, but if successful, this strategy can be used to rapidly drive up warscore by rapidly taking control of large numbers of provinces, especially in cases where the opponent does not yet have land tech 5 and thus cannot reply in kind. (This commonly happens in Europe for a short time in the late 1400's, and also in wars between European and non-European nations.)