why did japan invade manchuria?

Japan invaded Manchuria primarily to secure natural resources, create a territorial foothold in China, and protect its economic interests, especially amid the global economic depression. The immediate pretext was the Mukden Incident in 1931, a staged event by Japanese military personnel that involved a minor explosion on a railway they controlled, which Japan blamed on Chinese forces as a justification to invade. Japanese militarists saw control over Manchuria as vital to Japan's industrial growth, military strategy, and as a buffer against the Soviet Union. The invasion also reflected Japan's desire to expand its imperial influence and was fueled by nationalist and militarist ambitions within the Japanese military, which bypassed the civilian government in Tokyo to execute the takeover. The occupation led to the establishment of the puppet state of Manchukuo and marked the beginning of broader aggression by Japan in China, setting the stage for the Second Sino-Japanese War and contributing to tensions leading up to World War II.