Ishiwara's experience in Europe, as well as his adherence to the Nichiren sect of Buddhism, led him to theorize that in the future, Japan would engage in an apocalyptic war with the United States. This struggle, which he dubbed "the Final War," would be a protracted total war in which airpower would play a decisive role. Ishiwara believed, however, that Japan could overcome its material inferiority by harnessing the economic resources of the Asian mainland, especially Manchuria and Mongolia. He published his theories in a book entitled Thoughts on the Final Global War.
In 1928, Ishiwara was posted to Manchuria, where he served as chief of operations for the Japanese Guandong (Kwantung) Army. Impelled by his sense of the urgency of preparing for the Final War, Ishiwara played a major role in planning and carrying out the Japanese army's seizure of Manchuria beginning in 1931. Shortly before the establishment of the puppet state of Manzhouguo (Manchukuo) in 1932, he returned to Japan. Promoted to colonel, he headed the Operations Section of the army General Staff. After becoming a major general, he was in charge of General Staff's Operations Division. Nonetheless, Ishiwara's considerable earlier influence as a military theorist waned during the 1930s. Marginalized for his tacit support of a failed officers' rebellion in February 1936, as well as for his increasingly outspoken criticism of Japan's war with China (he was chief of staff of the Guandong Army in 1937 and 1938), he was promoted to lieutenant general but was forced into retirement in 1941.
Ishiwara headed the Toa Remmei (East Asian League), which opposed Premier Tojo Hideki's policies during the war. He briefly returned as an adviser to the "Surrender Cabinet" and urged that Japan conclude a peace.
Following the war, Ishiwara was investigated by the Allied occupation authorities, who briefly considered trying him as a war criminal. Instead, he testified as a prosecution witness at the Tokyo War Crimes Trials in 1947. Ishiwara died in Akita Prefecture on 15 August 1949. John M. Jennings
Barnhart, Michael A. Japan Prepares for Total War: The Search for Economic Security, 1919–1941. Ithaca, NY: Cornell University Press, 1987.; Peattie, Mark R. Ishiwara Kanji and Japan's Confrontation with the West. Princeton, NJ: Princeton University Press, 1975.
John M. Jennings