The Axis powers, made up of Nazi Germany, Facsist Italy, and the Empire of Japan, were the main countries who fought against the allies in World War II. They were united by their fascist goals and objectives, although they did not all share Hitler's obsession with racial purity. The surrender of Germany and Italy, and the atomic bombings of Hiroshima and Nagasaki.
The German and Italian intervention in the Spanish Civil War bought Hitler and Mussolini closer together, and in 1936, and Japan became involve in the pact in 1937, after being suppoted by Germany in its opposition of Communist Russia. However, the pact was finalised in 1940 when Germany, Italy, and Japan signed the Tripartite Pact in Berlin.
Germany was the unnoficial leader of the alliance, as it had authored the Tripartite Pact.
German citizens felt that their country had been humiliated as a result of the Treaty of Versailles at the end of World War I in which Germany was forced to pay enormous reparations payments, and forfeit German-populated territories and its colonies. The pressure of the reparations on the German economy led to hyperinflation during the early 1920s. In 1923, the French occupied the Ruhr region as a result of late payments leading to greater feelings of discontent. Although Germany began to improve economically in the mid-1920s, the Great Depression created more economic hardship and a rise in political forces that advocated radical solutions to Germany's woes. The Nazis under Adolf Hitler followed and promoted the nationalist stab-in-the-back legend stating that Germany had been betrayed by Jews and Communists and promised to rebuild Germany as a major power and create a Greater Germany that would include Alsace-Lorraine, Austria, Sudetenland, and other German-populated territories in Europe. In addition to this, the Nazis aimed to occupy non-German territory of Poland, Baltic countries, and the Soviet Union, to colonize with Germans as part of the Nazi policy of seeking Lebensraum ("living space") in eastern Europe.
During World War I, Italy had entered the war against Germany and Austria-Hungary. At the end Italy made fewer gains than it had been promised in the London Pact. The London pact was nullified with the treaty of Versailles, Italian nationalists and the public saw this as an injustice and an outrage; there had been over 600,000 Italian casualties. This resentment together with internal discontent and an economic downturn allowed the Italian Fascists under Benito Mussolini to rise to power in 1922.
In the late 19th century, after the reunification, a nationalist movement grew around the concept of Italia irredenta, which advocated the incorporation of Italian-speaking areas under foreign rule into Italy. There was a desire to annex Dalmatian territories which had formerly been ruled by the Venetians and which consequently had Italian-speaking elites. Italy's Fascist regime's intention was to create a "New Roman Empire" in which Italy would dominate the Mediterranean. In 1935-1936, Italy invaded and annexed Ethiopia and the Fascist government proclaimed the creation of the "Italian Empire". The League of Nations protested, however no serious action was taken, though Italy later faced diplomatic isolation from many countries. In 1937 Italy left the League of Nations, and in the same year joined the Anti-Comintern Pact signed by Germany and Japan the preceding year. In March/April 1939 Italian troops invaded and annexed Albania. Germany and Italy signed the Pact of Steel on May 22.
Italy entered World War II on June 10, 1940. In September 1940 Germany, Italy and Japan signed the Tripartite Pact. By 1941, however, the Italians had suffered multiple military defeats; in Greece and against the British in Egypt. It was only through German intervention in Yugoslavia, the Balkans and North Africa that Italy managed to avert a major military collapse. By 1943 the Italian people had lost faith in Mussolini and no longer supported the war; Italy had lost its colonies, the allies had taken North Africa in May and Sicily had been invaded in July.
On July 25, 1943, King Victor Emmanuel III dismissed Mussolini, placed him under arrest, and began secret negotiations with the Allies. Italy then signed an armistice with the Allies on September 8, 1943 and later joined the Western Allies as a co-belligerent. On September 12, 1943, Mussolini was rescued by the Germans in Operation Oak and a puppet state was formed in northern Italy (see "German puppet states" below), although it exercised little real power and Italy continued as a member of the Axis Tripartite Pact in name only. This resurrected Fascist state was referred to as Repubblica di Salò or the Italian Social Republic (Repubblica Sociale Italiana/RSI).
Japan was the principal Axis power in Asia and the Pacific. The Empire of Japan, commonly referred to as Imperial Japan, was a constitutional monarchy ruled by Hirohito. The constitution prescribed that "The Emperor is the head of the Empire, combining in Himself the rights of sovereignty, and exercises them, according to the provisions of the present Constitution" (article 4) and that "The Emperor has the supreme command of the Army and the Navy" (article 11). Under the imperial institution were a political cabinet and Imperial General Headquarters with two chiefs of staff.
At its height, Japan's Greater East Asia Co-Prosperity Sphere included Manchuria, Inner Mongolia, large parts of China, Malaysia, French Indochina, Dutch East Indies, The Philippines, Burma, some of India, and various other Pacific Islands - specifically in the central Pacific.
As a result of the internal discord and economic downturn of the 1920s, militaristic elements set Japan on a path of expansionism. Japan had plans to establish its hegemony in Asia and thus become self-sufficient, as the Japanese home islands lacked natural resources needed for growth, by acquiring areas with abundant natural resources. Japan's expansionist policies alienated it from other countries in the League of Nations and by the mid-1930s brought it closer to Germany and Italy, who had both pursued similar expansionist policies, which resulted in condemnation by a number of countries. Initial steps of Japan aligning militarily with Germany began with the Anti-Comintern Pact, in which the two countries agreed to ally with each other to challenge any attack by the Soviet Union.
Japan's first major action was against the Chinese in 1937. The subsequent Japanese invasion and occupation of parts of China resulted in numerous atrocities against civilians such as the Nanking massacre and the Three Alls Policy. The Japanese also fought skirmishes with Soviet–Mongolian forces in Manchukuo in 1938 & 1939. Japan sought to avoid potential war with the Soviet Union by signing a non-aggression pact with the Soviet Union later in 1941.
With European colonial powers focused on the war in Europe, Japan sought to acquire their colonies. In 1940 Japan responded to the collapse of France to the Germans, by occupying French Indochina. The regime of Vichy France, a de-facto ally of Germany, accepted Japan's takeover of Indochina. Allied forces did not respond with war. However, with the continuing war in China, the United States instituted in 1941 an embargo against Japan. This cut off the supply of scrap metal and oil needed for its industry, trade and war effort.
To isolate American forces in the Philippines, and American naval power, the Imperial General Headquarters ordered the Imperial Japanese Navy to attack the U.S. Naval Base at Pearl Harbor, Hawaii on December 7, 1941. The Japanese forces also invaded Malaysia and Hong Kong. The Japanese initially were able to inflict a series of defeats against the Allies, however by 1943 American industrial strength was made apparent and the Japanese forces were pushed back towards the home islands. The Pacific War lasted until the atomic bombings of Hiroshima and Nagasaki in 1945. The Soviets formally declared war in August, 1945 and engaged Japanese forces in Manchuria and northeast China.