Kuniaki Koiso

02.01.2012 ( Last modified: 09.06.2016 )
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Kuniaki Koiso was born on 22 March 1880 in Utsunomiya into an ex-Samurai family. He was a graduate of the Imperial Japanese Army Academy and took part in the 1904-1905 Russo-Japanese war.

Koiso then moved up through the ranks of the Japanese army and also set out on  a political career.

In February 1932, Koiso became Vice-Minister for War and in August 1932, Chief of Staff of the Kwantung Army (Manchuria). In 1938, he also joined the Japanese Army General Staff. From April-August 1939, and again from January-July 1940, he served in a newly created cabinet post as Minister of Greater East Asia (an institution in charge of the colonisation of the territories occupied by Japan). In May 1942, he was appointed Governor-General of Korea.

On 22 July 1944, following the resignation of Hideki Tojo he became Prime Minister.

Under his government, there was no improvement in the condition of the allied prisoners of war and that of civilians from the occupied countries whilst at the same time Koiso proved incapable of slowing the allied advance in the Pacific.

On 7 April 1945, Koiso was forced to resign when the American forces landed in Okinawa.

Kuniaki Koiso was arrested at the end of the war.


legal procedure

Kuniaki Koiso was arrested at the end of the war and was tried by the International Military Tribunal for the Far East (IMTFE) for war crimes as a Class-A war criminal.

He was found guilty on count 1 (conspiracy to wage wars of aggression against one or more countries, between 1 January 1928 and 2 September 1945) and counts 27, 29, 31 and 32 (for having waged wars of aggression) and count 55 (for not fulfilling his duties as a military commander by disregarding his duty to take adequate steps to prevent violations of the laws and customs of war).

In addition, the Tribunal concluded that due to his high rank in the Japanese military hierarchy, Kuniaki Koiso had played a decisive role in starting the wars against China and the allies. Furthermore, despite the fact that Kuniaki Koiso was not the instigator of the war crimes committed by the Japanese Army, he took no measures to prevent them or to punish the perpetrators when, as Prime Minister, it was fully in his power to do so.

On 12 November 1948, the IMTFE sentenced him to life imprisonment.

Kuniaki Koiso died on 3 November 1950 in Sugamo prison .




After Japan’s surrender in World War II, the victorious powers decided to a institute an International Tribunal aimed at trying those members of the Japanese establishment who were most responsible for the war of aggression waged by Japan and for other crimes perpetrated during the war. The Tribunal was established by means of a decree of the Supreme Commander of Allied Forces in the Far East, US General Douglas MacArthur, on 19 January 1946, amended on the following 25 April.

The IMTFE Charter reproduced almost verbatim the Charter of the Nuremberg Tribunal. The Tribunal had jurisdiction over allegations of crimes against peace, war crimes and crimes against humanity. Judges and prosecutors were chosen among the nationals of States who were in war against Japan (United States, Great Britain, Soviet Union, Australia, New Zealand, the Netherlands, France, the Philippines and China). The Tokyo Tribunal received the same criticisms moved to its German counterpart, concerning in particular the modality of its creation, the composition of the judiciary and the respect for the principle of legality. The public prosecution was lead by the American Joseph B. Keenan.

The proceedings at the Tribunal took place between 29 April 1946 and 12 November 1948. In total, 28 former Japanese generals and politicians were indicted. Remarkably, no proceedings were instituted against the then Emperor of Japan, Hirohito. Most accused were charged on counts of crimes against peace, concerning the aggressive policy implemented by Japan before and during the World War. All the defendants were convicted.  Seven of them were sentenced to death, most of the others to life imprisonment.


A number of other proceedings were held against Japanese war criminals before courts-martial or military commissions run by each of the victorious Powers. Overall, more than 5600 Japanese nationals were prosecuted, in more than 2200 trials. About 4400 people were convicted, and about 1000 of them were subsequently executed.


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