How to win a 20th-century battle

Raise morale

However well-equipped a force, troops must believe in what they are doing, that their cause is just and that they will win. The huge French conscript army in 1940 outnumbered the Germans but were fearful of a replay of the First World War and its massive casualty bill, as were its politicians. Thus, within six-and-a-half weeks the Wehrmacht, with no such doubts and fanatical belief in their nation’s policies, had defeated their adversaries. Morale is about digging deep in a moment of crisis, and persevering – as did exhausted RAF pilots during the Battle of Britain, sailors manning the Atlantic and Arctic convoys, or the citizens of Malta – the most bombed place on earth – believing they would somehow survive.

Keep your opponent guessing

During the first half of the Second World War, the Germans retained the initiative, choosing when and where to strike – whether this was in Poland, Norway, France, North Africa, Yugoslavia, Greece, or the Soviet Union. The side that chooses offensive action first (properly sustained) gains an advantage, forcing their opponent to react rather than develop their own plans. In this way, warfare is like chess, as British commanders found to their cost in the Western Desert, hampered by General Erwin Rommel, who seemed always to be one step ahead. The same quality, too, determined the early Japanese successes in the Far East, where the Allies were too stretched to defend everywhere equally effectively.

“Careless Talk Costs Lives”

The famous British World War Two poster reminded everyone – military and civilian alike – that security was an overriding necessity. Any overheard information might be of use to an enemy, so best to be on one’s guard at all times. On a battlefield this translated into making sure your own operating base was secure as you set off to attack your opponent. Thus, the perimeters of airfields were patrolled, and harbour entrances regularly swept for mines and enclosed with nets against submarine attack. On battlefields, troops protected rear areas and forcibly removed civilians so their supply routes would be safe. Partisans in the Soviet Union attacking the German road and railway network severely impeded German military effectiveness in 1943–5.

Harness the element of surprise

Surprise is the greatest weapon in war. It allows a commander to strike at a time and place of their choosing, when their opponent is off-guard. Thus, the 7 December 1941 Japanese attack on Pearl Harbor, Honolulu, caught the United States of America, then a neutral country, at its most relaxed, at 08:00am on a Sunday morning, causing great damage. Often surprise is coupled with deception, persuading your enemy you will do the opposite of what occurs, as with the invasion of Sicily on 9–10 July 1943, when the Allies encouraged Adolf Hitler to expect an invasion elsewhere. Surprise can lead a paralysis of decision-making, as generals are literally shocked into inactivity by the unexpected, which was the effect of the German blitzkrieg of May 1940 on the French high command.

• Read more: Why didn't America see Pearl Harbor coming?

Remember, quality versus quantity

Choosing where and when to concentrate your force is a basic skill required in every military commander. This is not always about numbers, but also the quality of troops – whether tiny numbers of SAS attacking the Afrika Korps behind German lines in Libya, or Chindits ambushing larger Japanese units in Burma. However, quantity has a quality all of its own, as the Russians found numerous times on the Eastern front, especially during Operation Uranus from 19 November 1942, the Red Army counterattack which surrounded Stalingrad.

“Amateurs Talk Tactics, Professionals Discuss Logistics”

The Second World War underlined the necessity for good military logistics, both in manufacturing the right quantities of good equipment, and in terms of transporting them – by land, sea, or air – to where they needed to be. The 2.4m trucks, 640,000 Jeeps and more than 49,000 Sherman tanks manufactured in the USA, and 84,000 T-34 tanks built in the Soviet Union, simply overwhelmed German industrial capacity, exacerbated by the Third Reich’s shortages of oil and other raw materials, such as rubber. Being on the winning side in a resource war would prove as important as raw military force.

Expect the unexpected

Most of the foregoing skills are the result of training and planning, but what if the unexpected happens? The Second World War, as in every conflict, is full of examples of the need to keep an open mind, retain flexibility, and always have a Plan ‘B’. This was typified by the US Army response to the sudden German attack of 16 December 1944 (the battle of the Bulge), when cooks, clerks and bandsmen fought in the forests around Bastogne, in Belgium. In many ways this is the supreme test for soldiers: good training should ensure that things turn out well in adversity, not only when operations are going to plan.

Don’t forget your friends and allies

Victory in both world wars and every other 20th century conflict fought by Britain, apart from the Falklands (1982), was the result of co-operation. Locally, this saw the combat arms on a battlefield – principally engineers, infantry, artillery, and armour – fully unite with their air forces. Early failures in both world wars were the result of these arms failing to liaise and integrate. In a wider sense, co-operation entailed working as part of a coalition or alliance. It was the arrival of the Americans into the war, with their vast industrial resources and quick-learning approach to conflict, which turned the tide. The idea of teamwork and sharing risk and capabilities between Allies proved to be war-winning on every front.

A winning combination

The supreme example of all these factors coming together was D-Day, 6 June 1944. The aim, to land in Normandy, was clear. Morale was high on account of realistic training and the common goal of defeating the Third Reich. The Germans were caught by surprise, partly through deception, and because Allied security was leak-proof. There were setbacks, the weather was awful, and the date altered at the last minute, but commanders and troops proved flexible. Overwhelming force was applied – over 150,000 troops were landed in 48 hours, supported by 12,000 aircraft. The invasion was incredibly well-sustained by a fleet of over 5,000 vessels, including warships of eight nations, and seen as a triumph of international co-operation. The success of Operation Overlord, in defeating Nazi Germany led, indirectly, to the founding of NATO in 1949, still in business as a military alliance today.

Peter Caddick-Adams is a full-time writer and broadcaster. He lectures at universities, military academies, and staff colleges around the world on military history, defence, and security issues. He also spent 35 years as an officer in the UK Regular and Reserve Forces, and has extensive experience of various war zones, including in the Balkans, Iraq and Afghanistan