The Mukden Incident, which occurred on September 18, 1931, was a staged event by the Imperial Japanese Army that served as a pretext for the invasion of Manchuria. Japanese troops detonated a small bomb on the railway line near Mukden (now Shenyang) and blamed Chinese forces for the attack. This incident was used to justify a full-scale invasion of Manchuria, leading to the establishment of the puppet state of Manchukuo.
The event was significant as it marked the beginning of Japan's aggressive expansion in East Asia during the early 20th century and highlighted the weaknesses of the League of Nations, which failed to take effective action against Japan's aggression. Japan's occupation of Manchuria ultimately contributed to rising tensions in the region, which would later escalate into broader conflicts, including the Second Sino-Japanese War and World War II.