How did Japanese expansion contribute to the onset of World War II?

Japanese expansion contributed to the onset of World War II by escalating tensions and triggering conflicts in the Pacific region.

In the early 20th century, Japan embarked on a path of aggressive expansion, driven by a desire for economic self-sufficiency and territorial dominance. This expansionist policy was a significant factor in the lead-up to World War II, as it heightened tensions and led to conflicts in the Pacific region.

Japan's invasion of Manchuria in 1931 marked the beginning of its expansionist policy. The invasion was a clear violation of the League of Nations' principles, which Japan was a member of. The League's failure to take decisive action against Japan not only emboldened the latter but also exposed the League's weakness, undermining the global peacekeeping mechanism.

In 1937, Japan initiated the Second Sino-Japanese War by invading China, further escalating tensions. The war was marked by Japan's brutal military tactics, including the infamous Nanking Massacre. These actions drew international condemnation and led to economic sanctions from the United States, the United Kingdom, and the Netherlands. The sanctions, particularly the US embargo on oil exports to Japan, severely impacted Japan's economy and military capabilities.

In response to these sanctions, Japan sought to secure its own resources by expanding further into Southeast Asia, which was rich in oil, rubber, and other resources. This brought Japan into direct conflict with Western colonial powers, particularly the United States and the United Kingdom, who had significant interests in the region.

The culmination of these tensions was the Japanese attack on Pearl Harbor in December 1941, which directly led to the United States' entry into World War II. This marked the beginning of the Pacific War, a major theatre of World War II.

In conclusion, Japanese expansion played a significant role in the onset of World War II. It escalated tensions, triggered conflicts, undermined international peacekeeping mechanisms, and eventually led to the United States' entry into the war.