German, "lightning war". A strategy based on an attack or attacks on a narrow front (the Schwerpunkt) using armoured and mechanized forces with strong tactical air aupport, with the intention of breaking through deep into the enemy's rear, bypassing defensive strongpoints and major troop concentrations (to be isolated and mopped up later by slower moving second-line forces) and disrupting communications for outflanked elements of the defending forces.
Although the desirability of breaching the enemy's front line and exploiting to their rear is as old as warfare itself, and the idea was certainly not discouraged by the initial success of the Ludendorff Offensive, the German's last successes in 1918, the doctrine of blitzkrieg, proprement dit, was a relatively short-lived one, depending as it did on the near-invulnerability of tanks facing infantry without heavy weapons; this came to an end with the development of portable anti-tank weapons such as the Panzerfaust and the bazooka in 1942 or so. It can really only be applied to three major campaigns by German forces: the invasion of Poland in 1939, the invasion of France and the Low Countries in 1940, and Operation Barbarossa in 1941. The other campaigns of the same period, in Norway and the Balkans, where the terrain was less tank-friendly, were rather more traditional infantry-based affairs.
The material requirements for a successful blitzkrieg attack were
- Local superiority - in both quantity and quality - in armoured and motorized forces. That doesn't just mean bigger and more heavily armed tanks (the Germans only moved onto that later in the war) - mechanical reliability and rapid availability of spares was also vital
- Operational flexibility - the ability to reorganise units and improvise to deal with situations as they happened. This was a strong traditional cultural feature of the German army.
- Air superiority. This was a vital aspect not merely for direct air support for attacks, but as a way of disrupting enemy communications - supplies and strategic movement - but also in order to protect the attackers' own fast-extending supply lines against attack. The Germans had invested considerably in mobile anti-aircraft guns and were able to protect vital supply routes as soon as they had been captured.
- A bad reputation amongst civilian populations. People fleeing the advancing Germans caused logistical problems for the defenders, blocking roads along which badly placed defenders might redeploy and, for the neutral countries which were invaded, making rapid mobilisation of reserves still more difficult.
- Weak, disorganised or badly handled opposition. The badly equipped Polish army was simply outclassed; the neutral status of Belgium and Holland meant that the French and the BEF were unable to deploy into those countries before the German attack, resulting in lack of coordination between the four armies, ending up with forces overcommitted towards the northern end of the front (where they in fact fought with reasonable success against the northern prong of the Panzer offensive before being outflanked and cut off). The Russian army, although large, had been hamstrung by Stalin's systematic purging of the officer class in the late 1930s.
- Fine weather - advances on a narrow front could not afford to become bogged down by sticky roads or blocked by swollen rivers, while good visibility was vital for air operations.
- Luck.
Although the German attack on France and the Low Countries in May 1940 seem like genius in retrospect, this was not universally held at the time, even among the participants. The drive through the Ardennes to the sea was conducted to the sound of desperate pleas from the commanders of the Panzer units to stop and regroup, allow the fuel and ammunition to catch up with them and, most of all, to secure the extremely exposed flanks of a 200 kilometer long salient, which nearly succumbed to a fairly weak British counterattack at Arras even as the Panzers were in sight of the sea; had the British and French managed to coordinate something a little more substantial, or had the Germans not had the foresight to equip their 88 mm flak guns with ammunition for ground use, the careers of Rommel and Guderian might well have ended up running out of fuel and ammunition in a pocket at Dunkirk, rather than forcing the Allies into the sea there.
The term was abbreviated to "blitz" which entered English both to refer to the aerial bombardment of London in 1940-41 - actually a static bombardment, quite different - and as a verb for any sudden overwhelming attack.
A chess match with extremely short time limits on the players, so that moves have to be made almost immediately.