German strategic theorists devised the concept of blitzkrieg to take advantage of the increasing power and reliability of the internal combustion engine, though the idea was not theirs alone. A number of military figures in several nations realized that static warfare was an outmoded concept and could be defeated by concentrating forces on a narrow point in a fast thrust.
The blitzkrieg worked to its greatest effect against small nations or those with limited defensive capabilities. The fall of Poland in 1939 and the capitulation of France in 1940 are textbook examples of the successes that a blitzkrieg strategy can attain.
Blitzkrieg is not without its disadvantages; there is a real danger of the attacking force overextending its supply lines, and the strategy as a whole can be defeated by a determined foe who is willing to sacrifice territory for time in which to regroup and rearm, as was seen in the Barbarossa? campaign of 1941.
see also Military History