The respective roles of Germany and Japan in the initiation and escalation of World War II seem similar on the surface—a combination of economic ambition and racist ideology. However, the countries’ root motivations and the ways in which they were expressed were fundamentally different.

Both Germany and Japan engaged in large-scale territorial conquests in the years leading up to World War II. Hitler and other Nazi officials in Germany advocated the concept of lebensraum, the natural “living space” required by what they considered the racially superior German people. Under this doctrine, Hitler claimed openly that German territory needed to be expanded through conquest of surrounding nations. Though some of Japan’s leaders held similar beliefs in the racial superiority of the Japanese people, they also had concrete motivations for territorial expansion: Japan’s population was growing too large for the confines of the Japanese islands, and colonial holdings in Asia were arguably becoming necessary to feed and clothe the Japanese people.

Also, Japan’s economic problems were far more severe than Germany’s. Although the German people were indeed humiliated by the terms of the Treaty of Versailles that ended World War I, Germany actually ended up not paying the bulk of the economic reparations that the treaty demanded. Rather, Hitler channeled the German people’s resentment to fuel his own schemes. Japan, however, though a victor in World War I, suffered when the United States and several European nations imposed high tariffs and blocked industrial imports. As a result, many Japanese people began to believe that whites were hostile to the idea of a developed non-white nation.

In response, Japan’s leaders asserted the superiority of their people and tried to change Japan into a colonial power itself, rather than a colonial subject. They therefore invaded and attempted to “develop” other Asian countries, including China and Korea. However, though Japanese policies in these countries were sometimes brutal, and often motivated by ideas of racial superiority, they were a far cry from the overtly genocidal goals of the Nazi death camps.

Ultimately, whereas Japan’s racist ideology and territorial ambitions grew as a result of real economic problems and Western exclusion, Hitler used Germany’s alleged economic woes and residual resentment from the Treaty of Versailles to promote his own racist ideas and premeditated plan to expand Germany’s borders.

World War II saw the new application of many new technologies by military forces on all sides of the conflict, and some of them had a profound impact on the war. The airplane in particular became a fundamental instrument of war and changed the way many battles were fought. Much the same may be said of the aircraft carrier, which became crucial to the United States after so many of its battleships were lost at Pearl Harbor. As a result of these developments, the Battle of Britain in 1940 marked the first time in history when air power alone determined the course of a major battle, and the Battle of the Coral Sea in 1942 was the first naval battle in history fought exclusively in the air, by carrier-based planes. Both sides also realized the effectiveness of radar as a way of warning against approaching enemy planes. Germany experimented with new missile technologies as well as both jet- and rocket-powered aircraft, but none of these projects was perfected in time to change the outcome of the war.

Although the majority of these new technologies had an effect on the war, they generally were created by one side in response to similar technologies being developed by the other side—the net effect of which was to balance out the new power these technologies offered. The notable exception was the atomic bomb, which the United States developed in secret from 1942 to 1945 and which Japan had no way to counter at the time. Indeed, Japan declared its surrender just days after the bombs were dropped on Hiroshima and Nagasaki in August 1945. Even today, however, historians debate whether the atomic bomb changed the outcome of the war, as Japan may have been already very close to surrendering.

Most historians concur that Hitler’s decision to invade the Soviet Union was one of the primary causes of Germany’s ultimate defeat. By invading the USSR, Germany made essentially the same mistake that Japan made by expanding so far across the Pacific. The huge expanse of the Soviet Union and the vast distances between its major cities required an enormous German invasion force. Despite this geographical challenge, Hitler assumed that Operation Barbarossa would take only six months, expecting Russia to capitulate rapidly after the shock of Germany’s initial, devastating attack. When events transpired differently, the German forces were faced with an enormous challenge, as their forces were dispersed and poorly equipped to deal with the brutal Russian winter. Russian soldiers and civilians, conversely, had plenty of room to retreat east when necessary, which caused the pursuing Germans to extend their supply lines so far that they were unable to maintain them. It was under these conditions that the Germans had to fight the massive battles of Stalingrad and Kursk. After the Germans lost both of these battles, they were no longer capable of maintaining their position and were forced to retreat to the west. Within a matter of months, the pursuing Red Army had pushed the Germans back through eastern Europe and toward a last stand on their home turf, which was the beginning of the end of the Nazi empire.