Germany, a rising European power from the 19th century CE onward, was one of the belligerents of World War I.
After it was defeated in that war, the victors subjected it to grueling indemnities.
This paved the way for the rise of Adolf Hitler and the nazi party.
He re-armed the country and progressively provoked the other great powers by first taking over his native Austria, next the Sudetenland and then annexing Czechia.
The world was astounded when Germany and the USSR, ideological enemies, signed the Molotov-Ribbentrop Pact in 1939 CE.
This alleviated Germany's fear of another war on two fronts and opened the way for Hitler's invasion of Poland.
Germany attacked in the same year and overran the country, though with some difficulty, but helped by the USSR that attacked from the other side.
Britain and France, who had been antagonized by Hitler's expansion, reacted by declaring war on Germany and thus (the European part of) World War II started.
The USSR pushed further west, forcing the Baltic states into accepting Soviet garrisons and fighting the Winter War against Finland.
On the western front, during the winter nothing much happened.
In the spring of 1940 CE the Germans surprised the allies by quickly conquering Denmark and Norway, among others using paratroops.
Shortly after the Wehrmacht launched its invasion of France.
Before the war, France had invested a huge amount of money in the defensive Maginot line along its border with Germany.
However the Germans, executing a plan concocted by general Erich von Manstein,
bypassed it through the Ardennes and cut the Anglo-French forces in two.
In just 6 weeks the Netherlands, Belgium, Luxembourg and France were overrun and Britain forced to hastily evacuate its army from Dunkirk.
Hitler, now in a position of power, extended a peace proposal to Britain, but it was rejected.
In the summer the Luftwaffe, the German air force, tried to gain air superiority for an invasion of the British Isles, necessary to overcome the strong British navy.
The Germans lost the Battle of Britain and switched to bombing raids instead.
Meanwhile in the east the fighting had started much earlier.
In 1931 CE the Japanese army, eager for power and economic opportunities, staged the Mukden incident and invaded Manchuria.
The professional Japanese easily overcame the Chinese, who were internally divided among communists, Kuomintang nationalists and local warlords.
The Japanese won in three campaigns spread over four years and subsequently set up the puppet state of Manchukuo.
In 1937 CE the Marco Polo Bridge Incident sparked the Second Sino-Japanese War.
The Kuomintang, now uneasily allied with the communists, tried to oust the Japanese from China.
The latter, outnumbered and suffering significant casualties, struck back with heavy violence, including a mass slaughter at Nanking.
The Chinese were numerically superior though had outdated weapons and were ill-organized.
The two sides were equally matched and after about two years the war descended into a stalemate, with Japan holding northeast China but unable to push deeper inland.
In 1940 CE Germany, Japan and Italy signed the Tripartite Pact forming the Axis Powers, though the pact was largely symbolical.
Later Hungary, Romania, Slovakia and Bulgaria joined in also.
Before the war the third party in this alliance, Mussolini's fascist Italy, had been a great inspiration for Hitler and his nazis.
Initially Italy was the senior power of the two, conquering Abyssinia in 1935 CE and Albania in 1939 CE.
Yet by the start of World War II the roles were reversed.
Mussolini wanted as much glory as Hitler and in late 1940 CE attacked Greece, only to be repulsed.
Italy's main ambitions were in Africa, however there too they were driven back by the British.
Hitler was forced to intervene and sent the Deutsches Afrika Korps under general Rommel to assist.
For two years the two sides swept back and forth in a struggle that was decided by supply lines.
Though very successful in western Europe, Hitler's intentions originally had not been to conquer it.
He wanted "lebensraum", living space, in the east.
Therefore he planned to betray the Molotov-Ribbentrop Pact and attack the USSR.
This was delayed by a month because the fighting in the Balkans forced the Germans to secure their right flank first.
In the spring of 1941 CE they overran Yugoslavia and Greece in another lightning campaign, Operation Marita.
Shortly after the Wehrmacht started Operation Barbarossa and poured into the USSR.
Stalin had been expecting a conflict with Germany, but not so soon.
His neglect of the Red Army and purges of the officer corps had left it in a very poor state.
The German army raced eastward and captured millions of Soviet soldiers in huge kettle battles.
It was halted just before Moscow due to overstretched supply lines, bad weather and stiffening Soviet resistance.
On the other side of the globe the USA, anxious of Japan's territorial ambitions, had imposed heavy economic sanctions on the country.
This, together with the German successes in Europe, convinced Japan to try to attempt to take on the USA.
The strategy was to deal a heavy blow, secure east Asia and build a ring of defensive Pacific islands before the Americans could retaliate.
This was executed through an attack on the Pearl Harbor naval base in late 1941 CE and offensives in southeast Asia,
which made the Second Sino-Japanese War part of the global conflict.
In just half a year Japan secured the Philippines, Singapore and the Dutch West Indies.
Then the offensive stalled in New Guinea and Burma.
In the Pacific ocean Japan fought a few heavy battles with the USA, which were costly to both sides.
But while the Japanese war industry was running on full power, the American one was just starting up.
World War II, more than any other preceding conflict, was a war fought by and for industrial power.
Most strategic offensives were aimed at securing economic resources.
Germany sought living space, food, minerals and oil in the east.
In 1942 CE, after the winter pause, it resumed its offensive inside the USSR.
Operation Blue focused not on Moscow, but on the rich resources of the southern Soviet Union.
It secured the Ukraine food basket, though failed to penetrate the oilfields of the Caucasus.
Japan, lacking in minerals and oil too, fought to secure them in east Asia.
Attacks where launched not only to gain resources, but also to deny them to the enemy.
Like in World War I the Germany and Britain tried to strangle each other's oversea supply lines.
Early in the war sea mines were the most important weapon.
Later surface ships and submarines became dominant.
The German U-boats had two 'happy times', from 1939 CE to 1941 CE and in 1942 CE, during which they came quite close to success.
Ultimately they were defeated by steadily improving counter-submarine warfare.
In the Pacific, it was the Axis powers who suffered most from American submarines that progressively choked Japan's supply lines.
Only in 1943 CE did the tide of the war decisively turn against the Axis Powers.
Despite lagging in behind in industrial capacity, though helped by western aid, they managed to produce more weapons than the Germans.
The Soviets destroyed an entire German army in the bitter Battle of Stalingrad.
They started to make serious counter-offensives and won the Battle of Kursk,
depriving the Wehrmacht of its last real offensive capability.
In Africa Rommel was driven back to Tunesia and then out of it.
British, American and Free French troops landed in Sicily and next on the Italian peninsula.
Mussolini fell from power and Italy out of the war.
The Germans immediately took over and started a skillful tactical retreat through the Italian peninsula that lasted 1½ years.
In the Pacific theater the USA closed in on Japan in a relentless campaign of island hopping, while the Chinese on the mainland played for time.
During its six years, the war steadily grew more brutal.
After the failed Battle of Britain and the equally failing attacks on English harbors, Hitler ordered Britain to be bombed into submission.
The British, later joined by the Americans, struck back by bombing German cities.
These attacks were very costly in terms of bombers and crews, but did seriously hamper German industry.
Not satisfied with that, Britain in 1943 CE started to drop incendiaries on German cities, causing massive civilian casualties.
Hitler tried to gain the upper hand with V-1 flying bombs and V-2 rockets, though their impact was mostly psychological.
In the Pacific theater, Americans equally harshly bombed Japanese cities into rubble.
As many Japanese houses were made of wood, fires caused enormous destruction.
In 1944 CE the initiative had passed to the allies.
The USSR launched Operation Bagration.
Largely bypassing the Baltic states, it drove the German armies back to Warsaw.
The Poles rose up in revolt, but the Soviets were both unable and unwilling to come to their aid and many Poles died in the following German revenge.
Another offensive in the Balkans broke away several allies from Germany, some of whom soon turned against it.
In the west, long awaited, American, British, Canadian and Free French forces landed in Normandy on D-Day.
After a period of difficult fighting they broke out of their beachhead and quickly liberated France, almost trapping the whole of the western German army.
By autumn they had reached the Rhine river, yet an ill-planned Operation Market Garden failed to get them across.
Germany struck back one more time, in the Ardennes Offensive, which failed to achieve its desired breakthrough.
In 1945 CE the allies broke into the German heartland from two sides.
Facing less resistance than the Soviets, the western powers were able to reach Berlin first, yet left the city to the latter.
In a costly battle the German capital was conquered and Hitler committed suicide.
Soon afterwards the German army surrendered.
In the Pacific, the the Japanese navy and air force sought to beat the Americans back in grand battles
in the the tradition of the Russo-Japanese War,
only to suffer shattering defeats and being destroyed step by step.
Despite the losses, Japanese resistance remained fanatical, just like the German efforts in Europe.
Kamikaze pilots turned fighter airplanes into flying bombs and fights over some islands where almost to the last man.
But the Americans had just developed a new weapon: the atomic bomb.
Two were dropped, on Hiroshima and Nagasaki, tipping Japan's stance over.
It capitulated too, ending the war.
The 'blitzkrieg' tactics used by both Germany and Japan had gained them strong positions very rapidly, but failed to bring down the allied powers.
Strategically, the latter turned the war into a battle of attrition where their greater economic power gave them a decisive advantage.
Tactically, they adopted the same methods of fast mobile warfare that had made the Germans and Japanese so successful.
Military technology developed rapidly during the war.
Tanks established their dominance on the battlefield and became a lot heavier during the war.
They were joined by motorized troops
and later mechanized infantry and self-propelled artillery,
creating a mobile type of warfare that used the combined arms principle.
At sea battleships were rendered obsolete and replaced by aircraft carriers.
Aircraft, both in a tactical and strategic sense, established themselves as a third pillar of armed forces next to armies and navies.
After the war Germany was cut in four parts, later reduced to two.
The USA and USSR, allies in the war, emerged as superpowers.
They soon fell out with each other and started the Cold War.
Stalin transformed eastern Europe into a vast buffer zone; the USA made Japan a shield against the USSR and China.
To prevent further wars, the United Nations were set up as a mediating platform.
Ironically, both great losers of the war, Germany and Japan, who had sought to become superpowers too, recovered quickly and went through a period of very solid economic recovery,
while two victors, Britain and France, lost their colonies within a few decades and were reduced to medium sized powers.
Both sides in the war, but especially Germany, Japan and the USSR, committed war crimes, killing civilians on a large scale.
Prisoners were used as forced laborers, sometimes starved to death.
Nazi Germany was the most brutal, deliberately executing 6 million jews, gypsies, homosexuals and others.
The death toll of the war was astounding: some 60 million in total, 1/3 of them civilians.
In terms of absolute numbers the USSR was hit the hardest, losing 24 million people;
in relative terms Poland, the Baltic states and Germany suffered the most, up to 20% of their pre-war population.
War Matrix - World War II
World Wars 1914 CE - 1945 CE, Wars and campaigns