World War I proved that the machine gun, supported by artillery, can stop whole armies on its tracks and positional warfare leads to costly stalemate. Defense reigned supreme. To avoid a repetition of these pointless battles, European military theorists searched for ways to pierce these strong defensive lines with new tactics, like infiltration, and new weapons, like the tank.
Eventually, tactical concepts developed into operational doctrines. Russian, British and German armies of the mid 30’s arrived at a solution whose approach was, on paper, remarkably similar. The common idea comprised a method of attack using the tank as the main weapon to breach the defenses followed by a penetration of the enemy lines in great depth using motorized troops to prevent the enemy from establishing a new defensive line in the rear.
By keeping the offensive from the first day to the last of the hostilities, the defender would lose its freedom of action while the attacking army would retain the strategic initiative until victory was on its hands.
The German and Soviet armies became very offensive oriented with the adoption of this formula and both invested heavily to make it work. However, the Germans were much more successful in practice. The name Blitzkrieg, used to christen this doctrine, emerged after the first dramatic success in Poland in 1939. Its effectiveness came as a shock not only to the enemy but also to many conservative thinkers in the German Army that initially were against it. German generals Heinz Guderian (Heer) and Walther Wever (Luftwaffe) , its main exponents, were right, as was Hitler, who supported them.
The blitzkrieg is a method to conduct and win the air-land battle using combined-arms teams consisting of aircraft, tanks, mechanized troops and infantry.
The approach is bottom-up. Defeating enemy soldiers similarly armed is a hazardous enterprise.
Destroying every enemy formation implies substantial losses and these operations are time consuming.
Imagine that a group of 10 well-armed men appear in your neighborhood to rob a bank. Even if a powerful SWAT team deploys to neutralize them, you can immediately perceive that it will not be an easy task: it will take time and blood to do it. On the other hand, every soldier, tank or artillery gun has a weakness that renders them impotent: their finite capacity to carry with them ammo, fuel and food.
This carrying capacity is very low: an infantry soldier has a total load capability of some 30 kg (60 lbs.), including weapons, helmet, gas mask, food, gear and ammo. This translates into enough food for one to two days and ammunition, under intense combat conditions, for a battle that lasts an hour or two at the most. For instance, the German infantryman armed with a rifle or carbine had 2 cartridge pouches (each with 3 pockets) with a total capacity of 60 rounds.
A German tank, like the Panzer III Ausf. H had enough fuel for 160 km on the road (320 liters) and 99 projectiles for the main 50mm gun, plus 2700 rounds of ammo for the machine gun. This was sufficient for a two-day advance and a couple of intense fire engagements, depending on the intensity of operations.
Once a soldier uses up its ammunition, its status changes from a ferocious warrior to a uniformed civilian. A tank without fuel and ammo becomes just a heavy immobile vehicle by a roadside.
This low-carrying capacity requires a logistics system to keep the armed forces supplied using a conveyor-belt type operation. Without resupply fuel, food, and ammo do not last long and any military unit loses all its fearsome effectiveness. An unsupplied army can only flee or surrender. How can fighting continue if the troops do not have the means to defend themselves?
Encircled troops do not surrender because they become disheartened. They surrender when they exhaust their supplies. To the layman, it may appear strange why so many soldiers surrender instead of fighting to the death. In practice, the reason is that the ammunition stock ended before the will to fight.
Preventing the enemy from resupplying its troops is then an effective way to eliminate large enemy formations quickly and at lower cost. But how to do this? The fundamental principle of the blitzkrieg was to encircle and destroy the adversary. To do that, the Germans deployed tanks to breach the enemy defensive line at tactical depth to achieve a breakthrough (durchbruch). Tanks have armor plate and are impervious to machine gun fire, so they can move over terrain defended by light forces armed with small arms. The Germans used tanks en masse to saturate the defenders and overwhelm the few anti-tank guns present in the attacked sector, carefully selected beforehand by reconnaissance troops precisely for this reason. After a successful breakthrough, additional mobile troops penetrated deeply through the breach towards the enemy rear, by-passing pockets of resistance in a maneuver called exploitation, obstructing any enemy’s supply columns encountered. The mobile troops continued their advance until the encirclement of the opponent was complete, thus foiling its resupply for good.
Lastly, friendly infantry penetrated through the gap, and marching on foot on the wake of the mobile troops, arrived to consolidate the encircling ring preventing an enemy break-out. Then, the infantry battalions forced the encircled enemy to do battle and fire, causing it to spend its ammunition and surrender.
This deep penetration however, creates a serious vulnerability problem. Troops on the march are much more exposed than troops deployed in static, well dug-in defensive positions. They are also more visible, presenting an easier target: the columns of dust generated by motorized columns on the move are conspicuous from many miles and can attract artillery fire like a magnet. At the same time, the profound penetration means that troop density is sparse. A Panzer division advancing is a thin column 110 km (70 miles) long. However, by design, a divisional-sized unit can defend a sector 10 km (6 miles) wide or fight a delaying action over a 20 km (12 miles) frontage. Troop density is therefore too thin to protect an exposed flank of this magnitude unless the advancing troops have time to concentrate in a specific sector to defend.
An enemy counterattack against the flank of mobile forces pressing forward can be shattering: it can overrun the encircling units and dislodge their supply. Legend has it that panzer leaders had nerves of steel and disregarded their flanks. This is a half-truth.
The use of a tactical air-force helped to solve this problem and by design, it was an indispensable part of the combined-arms, Blitzkrieg concept. The Luftwaffe had 4 main missions to play within this doctrine:
First and most important was the attainment of air superiority. The German bombers started to bomb enemy airfields right at the outset to destroy enemy aircraft on the ground and their supporting infrastructure (maintenance hangars, fuel and ammo depots and command centers). Fighters would fly aggressive hunting missions over enemy territory to shoot down any enemy aircraft that attempted to respond. The aim was to gain control of the volume of airspace above the friendly mobile troops and some distance beyond creating a large bubble where the German aircraft could execute their missions and the enemy aircraft could not. Fighters played the most decisive role in this mission.
With the achievement of air superiority, reconnaissance aircraft flying ahead of the mobile divisions identified enemy troops deploying defensively or offensively and military units moving rearward or forward. This crucial intelligence allowed the friendly mobile forces to set up defensively with sufficient time in case of a hostile counterattack, concentrating strength opposite the enemy axis of advance.
Simultaneously, the armored combat groups (kampfgruppen) could carry out spoiling attacks on the flanks of the enemy counterattacking units, forcing them to abandon their assault. This aerial mission by itself reduced dramatically the threat on German mechanized formations because it provided them the initiative, affording the panzer leaders the confidence to move forward knowing that their flanks were under vigilance.
The nature of this observation mission is analogous to the use of radar by the British during the battle of Britain: radar allowed the RAF to detect attacking Luftwaffe formations and use Fighter Command squadrons only at the points of their choosing. Of course, radar was unsuitable to detect enemy units on the ground, but the human eye and photographic cameras are effective sensors. Air-reconnaissance squadrons scanned broad sectors around the advancing panzer divisions and disseminated vital information to the appropriate commands. Then, reemphasizing, the ground commanding officer directed some formations to defend specific vulnerable zones that the enemy was approaching while he ordered other units to attack the adversary’s forces on the march at a time when they were most vulnerable. Like in the air battle over Britain, small formations (in this case mobile troops) concentrated in space and time could act decisively.
War games reveal that the side that can identify size, placement and direction of movement of enemy’s formations (i.e. “armored brigade outside of Brest moving westward”) has an enormous advantage over the side that does not have this intelligence. Air superiority allows own aircraft to observe and inform on enemy’s intentions, while it turns the enemy blind.
Third, Luftwaffe bombers attacked the enemy troops located by the recce aircraft to reduce the speed of movement and degrade their capabilities. They also bombed command post to hinder coordination efforts and communication networks (roads and railroads), selecting specific infrastructure bottlenecks (i.e. bridges, rail junctions), whose destruction prevented or reduced enemy’s reinforcement and resupply capabilities. The Luftwaffe did not have enough bombers to obliterate large enemy fighting groupings (i.e. brigades or higher), but it had sufficient strength to create holdups to enemy movement, securing time for the German mobile forces. Aerial strike forces were also strong enough to impair significantly the supply condition of enemy formations making them brittle. Contrary to widespread belief, the horizontal and dive bombers dedicated more effort to interdiction in the rear zone than to striking enemy troops in the battle area. There is a very good reason for this. In the battle area, the deployed enemy companies scatter and dig-in on their sectors to minimize detection and to reduce casualties in case of a hit. Aerial bombing is most effective against clearly defined targets that are relatively stationary and compact, conditions that are hard to find in the battle zone. Furthermore, most of the enemy anti-air defenses are precisely in the battle area, increasing bomber losses. On the other hand, it is easier to destroy fuel and ammunition trucks traveling in long exposed columns on roads or on freight trains and it is just as effective: a tank becomes impotent by lack of supplies even if it remains undamaged.
In comparison, the attack of enemy ground troops opposing the advance of armored formations played a secondary role. The use of Luftwaffe aircraft as aerial artillery, very often mentioned by several authors as the key role of the German air force, only played an important part when the war of movement was starting or when it was momentarily on hold. When these conditions were prevalent, the bomber wings would strike the enemy defending prepared or fortified defenses that were easily identifiable (for example, across a river, in a town or forest). Even in those instances however, the sorties dedicated to this form of attack were relatively small. Given the tremendous frontage of the eastern front, ground troops proved consistently able to find suitable weak spots on the enemy defense to perforate it without the support of strike aircraft.
Air superiority, again, permitted the bomber force to roam at will whereas the enemy strike force would suffer devastating losses attempting to destroy the juicy targets on the roads.
The last aerial mission that the Luftwaffe executed during the blitzkrieg was logistic support by transport aircraft. The logistics of a fast-moving army are daunting, and crisis occur frequently. Supplies delivered by air to the forward troops (spearheads) strengthen the capabilities of the supply system allowing the war of movement to maintain momentum.
Thus, the German air force main effort focused on supporting the exploitation, not in achieving the breakthrough.
Luftwaffe assistance to support ground offensives proved decisive. No German large-scale offensive ultimately succeeded in any front unless under conditions of friendly air superiority. Similarly, the Russians found nearly impossible to sustain deep ground advances while under air inferiority conditions, unless they attacked protected by harsh weather or by spreading their attacks along the whole front to prevent the German air force to concentrate against a single all-important assault.
The importance of the Luftwaffe in the large expanses of the Russian hinterland was even more vital than in more restricted theaters of war, because counterstrokes could come from any unobserved place. As a result, the German air force concentrated all its available strength in decisive axes of advance or sectors, while the rest of the German ground formation received minimal support.
Upon completing a successful encircling operation, another would start, making it very difficult for the enemy to establish a new strong line of resistance. However, reserves in great depth are a good defensive strategy against a Blitzkrieg offensive because penetrations deeper than 300km were very difficult to achieve in one swoop.
The Blitzkrieg offensive mechanism may appear like an irresistible formula to win the battle, but in practice it is enormously complex to implement. Marshal Mikhail Tukhachevsky in Russia, with the full support of Stalin, attempted to do the same thing, even adding large paratroop forces to the recipe, but he failed. This may have cost him his life.
To make it work the Germans solved many teething real-world problems both in the ground and in the air:
They created from scratch, armored divisions organized such that all the arms: infantry, artillery, tanks, and supporting troops (engineers, recce, flak, anti-tank, signals, etc.) could move at the same pace.
They designed new equipment for these mobile troops and developed specialized training so they could execute their missions with proficiency. The Germans also created a command organization able to receive real time information from multiple ground and air sources; process this information to create a picture of the situation; trained officers to make right decisions quickly and developed communication systems to disseminate the orders so they could reach the required troops on the move on time.
Highly aggressive and mobile recce troops moving ahead of the main body were available to identify suitable terrain and strength of enemy defenses. With this information, divisional commanders redirected the movement of battle groups to maintain the momentum of advance.
They developed a tactical air arm able to carry out the 4 missions outlined previously, supported by an organization that allowed operations from recently captured airfields.
A sufficiently large defense-industrial complex and training organization that permitted the deployment of sufficient force to break defenses, attack en masse and protect themselves while moving underpinned the whole effort.
Finally, they established a supply and maintenance organization that allowed the armies to keep moving and fighting. This problem was a major nightmare because delivering immense quantities of material to troops that are far from the supply centers and changing position every day is an enormous task.
The German army developed and implemented the Blitzkrieg operational doctrine brilliantly. After successive improvements prompted by multiple real-life exercises and the experience of battle, the Germans transformed it into a ruthlessly effective method to carry out and win the air-land battle .
The Enemy MLR (Main Line of Resistance) is the red thick line. The defender is supplying its troops through the railroad that drops stores at the railhead (1) and thence to the depot (2) by road. Lower echelon transport then delivers the supplies to the troops (3). Enemy tactical reserves, deployed some distance from the MLR, are ready to plug any holes if necessary (4).
Operational reserves, kept well behind the front, are available to the defending commander to counter-attack and force the attacker to withdraw (5). The defender air force occupies the airfields to the east of the MLR (6).
The Germans have deployed fighters (7) and bombers (8) in airfields close to the front and within striking distance of enemy airstrips.
Infantry formations occupy positions along the MLR while the main attacking forces, formed by armored units supported by infantry elements deploy, using high-unit density, over suitable terrain (9).
Finally, the Germans place their reserves near the expected breakthrough points (10), ready to exploit and to widen the breach.
Luftwaffe bombers attack enemy airfields (1) while fighters shoot down any enemy plane that attempts to intervene (2), creating a 3D bubble of air superiority over the battlefield (3). Simultaneously, mixed infantry and armor battlegroups attack the weak spots on the enemy defense complex piercing the line of defense at tactical depth and therefore, achieve breakthroughs at two points (4). Bombers support one of the attacks directly to wreck enemy fortified defenses (5). Infantry and armored reserves behind the breakthrough points prepare to move forward (6).
The armored battlegroups push forward through the breach severing the railroad at two points (1). Infantry follows behind as fast as possible (2). Other infantry units pin the enemy troops in the original MLR to prevent their withdrawal (3). Observation aircraft carry out intense reconnaissance to detect any movement or threat ahead and in the flanks of the advancing armored units (4). German bombers isolate the battlefield by destroying identified hostile supply columns preventing enemy resupply (5) and any identified enemy units attempting to counterattack or to withdraw (6). Reconnaissance aircraft reports flow to the appropriate ground commands who deploy troops in the exposed sectors (7) while fighters continue aggressive hunting preventing the enemy air force from carrying out its missions (8).
Armored troops close the pincers encircling a considerable number of enemy troops (1). Infantry following behind consolidate the pocket, preventing enemy elements to escape. Then, they start attacking the surrounded troops to force them to fire and consume their ammunition (2). With the supplies gone, the enemy surrenders and the Germans grasp the fruits of the attack.
German aircraft move to bases farther ahead (3) to continue intense observation, maintain air superiority and attack threatening columns thus allowing the elimination of the isolated pockets (4). Once the destruction of the pockets is complete, a new operation starts.