For the long-forgotten OP, the question is why the Japanese were so cruel in WWII.
The quick answer is the Japanese militarism which became increasingly strong through the 1920s and then into the 30s and then the war. Bushido has a little to do with it as Christianity does to the Westboro folks, it was hijacked to service a more evil purpose. This is evidenced by the normal treatment of POWs by the Japanese in the Russo-Japanese war. It was only in the 30s that the army became so cruel. With universal conscription, the army drilled compliance into a populous which wasn’t that long out of a feudal system.
The structure of the Meiji Constitution created a structure which allowed militarism to develop unchecked by the civilian government. The Ministers of War (Army) and Navy had to be active duty officers, and the prime minister had to resign if he could not fill a cabinet, so he was at the mercy of the armed forces. The general staffs of the army and navy were independent of the respective ministries, and like the ministers, they reported not to the Prime Minister but directly to the emperor.
The ultra-nationalists attempted a number of coups, assassinated many government leaders and even threatened admirals who opposed them, ultimately unilaterally starting the war in China which lead to war with the Allies.
There is no doubt that the acts of the Japanese during the war were despicable. One searches in vain for words to adequately describe the unspeakable horrors.
The question is then why the Japanese didn’t develop the same sense of collective guilt which the Germans did after WWII. Many people point to this and try to make comparison, but there were large, material differences between the situations concerning the two Axis nations.
More German people were more involved in the rise of Nazism, which was a political party that received a plurality of votes, did enjoy the support of sizable percentage of the people. Hitler’s ascension to power in the early 30s was famously cheered on by large crowds of tens or hundreds of thousands. More Germans were active participants in the anti-Jewish laws and agreed with the Nazis that the Jews were a major problem which needed to be solved (although fewer knew about the death camps). The brutality occurred not in some far distant land but its own neighborhoods and its victim included its own citizens.
In contrast, in Japan the militarism was centered on the army and members of the non-elected ruling oligarchy. The violence occurred overseas, mostly out of view and knowledge of the average civilian. No one was rounded in the streets of Tokyo and political parties were suppressed rather than serve as an instrument of gathering public support. Political leaders did not spew hate-filled diatribes to cheering crowds.
There were major differences between how the wars ended and the timing and most importantly of how the Allies approached the issue. The land war on the European continent exposed the worst of Germany’s secrets to the world. The camps still stood and evidence of the massacres were there for all to see. Not only were they visible, but the Allies had enacted a wide-spread campaign of to rid Germany of Nazis and their sympathizers, forcibly bringing the atrocities to everyone’s attention. It was Allied pressure which was the impetus for the laws which ultimately banned the denial of the Holocaust.
In Japan, however, the war took several months longer, and the Japanese army was not overrun in areas where they had committed many of their atrocities. Even by then, there were concerns over the Soviet Union, and at least partly due to this the US Army participated in the cover-up of Unit 731. China’s attention was immediately distracted by its civil war. A critical part of the puzzle is that the US cooped the emperor in changing the nation, and was complicit in the cover-up of his responsibility. With the vast majority of the problem stemming from the then disbanded military, GHQ did not conduct an extensive propaganda campaign to impose a collective guilt on the Japanese population
Japanese intellectuals were highly critical of the militarism and successfully fought displays of the flag and the national anthem at school graduations for years, to take one example.
Timing is everything. With the successful cover-up of the worst of the civilian atrocities, including the Rape of Nanking, the Comfort Women and Unit 731 until decades later, when the news did come out, the shock value was considerably less. Less people could directly relate.
This is not an apology for the actions of the Japanese. Note my repeated use of words such as “atrocities.” Nor it is an excuse for the lack of earlier, clearer apologies and an honest approach to history.
It is, however, my opinion on why comparisons to Germany are not as black and white as some would think or claim.