Seishirō Itagaki (板垣 征四郎, Itagaki Seishirō, 21 January 1885 – 23 December 1948) was a General in the Imperial Japanese Army in World War II and a War Minister. Convicted of war crimes, he was executed in 1948.

Itagaki was born in Morioka city, Iwate prefecture into a samurai class family formerly serving the Nanbu clan of Morioka Domain. He graduated from the Imperial Japanese Army Academy in 1904. He fought in the Russo-Japanese War in 1904–1905.

From 1924-1926, Itagaki was a military attaché assigned to the Japanese embassy in China. On his return to Japan, he held a number of staff positions within the Imperial Japanese Army General Staff during 1926–1927 before being given a field command as commanding officer of the IJA 33rd Infantry Brigade based in China. His brigade was attached to the IJA 10th Division from 1927–1928. Itagaki was then transferred to command the IJA 33rd Infantry Regiment in China from 1928–1929, under the aegis of the Kwantung Army.

Itagaki rose to become Chief of the Intelligence Section of the Kwantung Army from 1931, in which capacity he helped plan the 1931 Mukden Incident that led to the Japanese seizure of Manchuria.^[1] He was subsequently a military advisor to Manchukuo from 1932–1934.

Itagaki became Vice Chief of Staff of the Kwantung Army from 1934, and Chief of Staff in 1936.^[2]

From 1937 to 1938 Itagaki was commander of the IJA 5th Division in China during the early part of the Second Sino-Japanese War. His Division took a leading part in the Battle of Beiping-Tianjin, Operation Chahar, and the Battle of Taiyuan. However, in the Battle of Xuzhou his forces were repulsed during the Battle of Taierzhuang in the vicinity of Linyi that prevented them from coming to the aid of Rensuke Isogai's IJA 10th Division.^[3]

Recalled to Japan in 1938, Itagaki briefly served as War Minister from 1938-1939. On December 6, 1938, Itagaki proposed a national policy in accordance with Hakko Ichiu (Expansion) at the Five Ministers Conference,^[4] which was the Japanese highest decision making council,^[5][6] and the council made a decision of prohibiting the expulsion of the Jews in Japan, Manchuria, and China as Japanese national policy.^[5][6]

Itagaki returned to China again as chief of staff of the China Expeditionary Army from 1939-1941. However, the defeat of Japanese forces against the Soviet Red Army at Nomonhan in the summer of 1939 was a major blow to his career, and he was reassigned to command the Chosen Army in Korea, then considered a backwater post.

As the war situation continued to deteriorate for Japan, the Chosen Army was elevated to the Japanese Seventeenth Area Army in 1945, with Itagaki still as commander in chief. He was then reassigned to the Japanese Seventh Area Army in Singapore and Malaya in April 1945. He surrendered Japanese forces in Southeast Asia to British Admiral Louis Mountbatten in Singapore on 12 September 1945.

After the war, he was taken into custody by the SCAP authorities and charged with war crimes, specifically in connection with the Japanese seizure of Manchuria, his escalation of the war against the Allies during his term as War Minister, and for allowing inhumane treatment of prisoners of war during his term as commander of Japanese forces in Southeast Asia. He was found guilty on counts 1, 27, 29, 31, 32, 35, 36 and 54 and was condemned to death in 1948 by the International Military Tribunal for the Far East. Itagaki was hanged on 23 December 1948 at Sugamo Prison, Tokyo.^[7]