Based on the principle of non-retroactivity of law, Justice Pal, first of all, explicated his criticism of the Tribunal’s ex post facto judgment in his Dissenting Opinion. He affirmed that the alleged ‘conventional war crimes’ by the Japanese defendants came within the jurisdiction of the Tribunal because they were already classified as crimes in pre-existing international law. However, Justice Pal opposed prosecution for ‘crimes against peace’, and ‘crimes against humanity’, as defined in the Tribunal’s Charter, because these crimes had no previous grounds in international law.
There were criticisms of the Tokyo Trial, which mostly centered around the American bias through the entire proceedings as well as the immunity enjoyed by members of the imperial family. Judge Radhabinod Pal of India offered a dissenting opinion, questioning the exclusion of western imperialism and the American use of the atomic weapons from the trial while Japanese imperialism and Japanese use of chemical and biological weapons were central to the Tokyo Trial.
Two of the accused Class A criminals, Matsuoka Yosuke and Nagano Osami, died of natural causes during the trial. Seven were found guilty and sentenced to death, with the executions carried out at Sugamo Prison, Tokyo, Japan on 23 Dec 1948. Those executed were: General Kenji Doihara, Baron Koki Hirota, General Seishiro Itagaki, General Heitaro Kimura, General Iwane Matsui, General Akira Muto, and General Hideki Tojo. 16 of them were sentenced to life imprisonment: General Sadao Araki, Colonel Kingoro Hashimoto, Field Marshal Shunroku Hata, Baron Kiichiro Hiranuma, Naoki Hoshino, Okinori Kaya, Marquis Koichi Kido, General Kuniaki Koiso, General Jiro Minami, Admiral Takasumi Oka, General Hiroshi Oshima, General Kenryo Sato, Admiral Shigetaro Shimada, Toshio Shiratori, General Teiichi Suzuki, and General Yoshijiro Umezu. Finally, Shigenori Togo received 20 years imprisonment and Mamoru Shigemitsu received 7 years imprisonment.
The only substantial defense put up for the accused as a whole was that they acted in self-defense... But the Nuremburg Tribunal decided that this does not mean that a nation can, by its own ipse dixit, convert an obviously aggressive war into a defensive one without reasonable grounds. The Tokyo Judgment points out the manifest absurdity of this contention on the facts of Japanese aggression for many years past; it therefore does not deal with the question whether mere economic actions without threat of armed hostilities, which was all that was alleged in this case, could ever justify a war of so-called "self-defense." The prosecution submitted that it could not.
The judgment adopts the Nuremberg decision that waging and conspiracy to wage aggressive war are in themselves crimes for which individuals can be convicted and punished... The Tokyo Trial, while putting this proposition in the forefront, also put the same facts in alternative charges of murder, a method not adopted at Nuremberg.
On the question of individual criminal responsibility, the tribunal held that "the principle of international law which under certain circumstances protects the representative of a state cannot be applied to acts which are condemned as criminal by international law. The authors of these acts cannot shelter themselves behind their official positions in order to be freed from punishment in appropriate proceedings."
Those put on trial were charged for war crimes in the following categories:
Class A charges, alleging "crimes against peace." These charges were brought against Japan’s top leaders who had planned and directed the war.
Class B charges covered "conventional war crimes." These charges were levelled at Japanese of any rank.
Class C charges covered "crimes against humanity." These charges were levelled at Japanese of any rank.
The Showa Emperor was the exception. A radical movement to pursue the Emperor as a war criminal developed among the core group of the newly re-established Communist Party, while from a different perspective, other groups, primarily intellectuals, began to favor the idea that the emperor ought to abdicate to accept a certain measure of war responsibility. The fact remains, however, that public opinion at the time supported the protection of the Emperor. An important factor here may have been the American anti-Japanese propaganda during the latter years of the Asia Pacific War. The U.S. tried to drive a wedge between the military, which it attacked, and the Emperor and the people, which it did not attack. This continued as part of Occupation strategy and the political myth that ‘the Emperor and the people were fooled by the military’ permeated deeply throughout the population. As a result, popular acceptance of criticism of military leaders and of the responsibility of leaders revealed at the Tokyo Tribunal gradually strengthened and coalesced around the exclusion of the Emperor from war responsibility.
Starting on 3rd May 1946 and ending in November 1948, twenty-eight Japanese leaders were tried before a panel of eleven judges. The judges came from Australia, Canada, France, Great Britain, India, Netherlands, New Zealand, the Philippines, USSR, and USA. The Philippines and India gained independence during the time of the trial. The mandate of the tribunal covered acts committed between 1st January 1928 and 2nd August 1945.
Following the Cairo Declaration of December 1, 1943, in which the United States, Great Britain, and China announced their determination "to restrain and punish the aggression of Japan" in the Far East theater, the Allies pronounced their policy regarding Japanese war crimes in the Potsdam Declaration on July 26, 1945.
"We do not intend that the Japanese shall be enslaved as a race or destroyed as a nation," read the declaration, "but stern justice shall be meted out to all war criminals, including those who have visited cruelties upon our prisoners."