Blitzkrieg
Germany's method of fast, concentrated combined-arms warfare, massed tanks and dive-bombers linked by radio, that overran Poland and France before either could react.
In the autumn of 1939 the world watched the German army do something armies were not supposed to be able to do: beat a large modern country in a matter of weeks. Poland collapsed in about five weeks. Then, in May and June 1940, France, the continent's strongest military power, was overrun in six. The method behind these shocks earned a name that stuck: blitzkrieg, German for lightning war. It was less a single written doctrine than a way of fighting built around speed, concentration, and surprise.
How it worked
Rather than spreading force evenly along a front, blitzkrieg massed armor at one narrow point, the Schwerpunkt or focal point, and punched a hole. Motorized infantry poured through the gap while the tanks kept moving, driving deep into the enemy rear instead of stopping to fight for ground. Overhead, Stuka dive-bombers served as flying artillery, plunging onto strongpoints and supply columns; the wail of the Ju 87's siren was meant to shatter nerve as much as anything it dropped. The connective tissue was the radio. Every German tank carried one, so fast-moving columns could coordinate and improvise on the move, while a slower enemy relaying orders by telephone and courier was encircled before it could respond. In May 1940 this was decisive: German armor threaded through the impassable Ardennes forest, crossed the Meuse at Sedan, and raced to the English Channel, trapping the best Allied armies in Belgium. Speed itself was the weapon, and it produced paralysis.
Where the idea came from
The roots ran back to the deadlock of World War I, where machine guns and trench lines had frozen the Western Front into four years of mass slaughter. In the 1920s British theorists, above all J.F.C. Fuller and Basil Liddell Hart, argued that independent armored formations could restore movement to war. In Germany, Heinz Guderian absorbed these ideas and forged them into a working system of tanks, aircraft, and radios operating as one, then fought the Wehrmacht's traditionalists to build divisions around it. Tellingly, the Germans themselves rarely used the word as a formal term. Blitzkrieg was popularized by the Western press and only later attached, somewhat loosely, to the tactics, which is why historians warn against treating it as a single tidy doctrine.
Why it stalled
Blitzkrieg was devastating but brittle. It was built to win fast because Germany could not win slow: it lacked the oil, manpower, and industrial depth for a long war of attrition. Against neighbors with short distances and open borders, lightning worked. Against the Soviet Union, it broke. The 1941 invasion, Operation Barbarossa, scored some of the largest encirclements in history, yet the sheer space swallowed the advance, supply lines outran the tanks, and the Red Army traded ground for time, kept fighting, and was resupplied by American Lend-Lease trucks, food, and machine tools. Once the war became the grinding contest of production and endurance that blitzkrieg was designed to avoid, Germany's early victories curdled into defeat.
The tactics outlived the regime that made them notorious. Massed armor, close air support, radio-linked speed, and deep thrusts became the grammar of modern maneuver warfare, studied in war colleges from the Israeli armored drives of 1967 to the American dash to Baghdad in 2003. The lightning was real. What it could never do was strike twice against an enemy too vast to knock out with the first bolt.