In 1929, Itagaki was attached to the operations planning staff of the Guandong (Kwantung) Army, the Japanese garrison force in southern Manchuria. After joining the Guandong Army, he and a fellow staff officer, Ishiwara Kanji, became the main instigators of a plot to manufacture an incident to use as a provocation to seize all Manchuria for Japan. On 18 September, a section of Japanese-owned railroad track was sabotaged just outside Shenyang (Mukden), the capital of Manchuria. Although Japanese officials on the spot immediately blamed local Chinese troops, the Guandong Army itself had sabotaged the track. This Mukden Incident provided the pretext for the Guandong Army to conquer Manchuria and establish the Japanese puppet state of Manzhouguo (Manchukuo). In March 1936, Itagaki became chief of staff of the Guandong Army. He was promoted to lieutenant general in April.
Itagaki remained in Manchuria until March 1937, when he took command of the elite 5th Infantry Division at Hiroshima, leading it in fighting against the Chinese in north China. In June 1938, he was recalled to Japan and served as war minister from January to August 1939. Itagaki then became chief of staff of Japanese forces in China. In 1941, he was promoted to full general and assumed command of Japanese forces in Korea. He remained in Korea until the last few months of the war, when he took command of the Seventh Area Forces in Singapore. On 12 September 1945, Itagaki formally surrendered Singapore and all Japanese southern armies to the British. Arrested for war crimes, he was brought to trial before the International Military Tribunal for the Far East. He was found guilty of conspiracy to wage aggressive war and wartime atrocities and was executed in Tokyo on 23 December 1948. John M. Jennings
Harries, Meirion, and Susie Harries. Soldiers of the Sun: The Rise and Fall of the Imperial Japanese Army. New York: Random House, 1991.; Ogata Sadako. Defiance in Manchuria: The Making of Japanese Foreign Policy, 1931–1932. Berkeley: University of California Press, 1964.
John M. Jennings