In September of 1931, anti-Japanese groups in China targeted a Japanese owned railroad in Manchuria, China. They used explosives to destroy the railroad, which greatly upset Japan. In retaliation, Japan invaded and conquered Manchuria. This created an international incident that is often linked to the beginning of World War II.
The Lytton Commission was established by the League of Nations to determine what caused Japan's invasion of Manchuria in 1931. The League of Nations was an international organization of nations aimed at resolving international conflicts in the wake of World War I.
The Lytton Commission was led by a British diplomat, namely, the Earl of Lytton. By the time the commission was established and began their work, Japan had already conquered Manchuria and established a puppet state that supported Japan. After spending six weeks in Manchuria investigating the conflict, the Lytton Commission determined that both Japan and China shared guilt in the conflict. China's guilt came from the fact that they had produced great amounts of anti-Japanese propaganda, while Japan's guilt came from the fact that they had acted aggressively in the conflict.
After preparing a report known as the Lytton Report for the League of Nations, a solution to the conflict was proposed. The Japanese puppet state of Manchukuo would not be recognized, and the territory would return to Chinese control, as had been the case before the conflict. While China agreed to these terms, Japan was opposed to them, and Japan withdrew from the League of Nations in protest.