The first thing that youre wrong on is the fact that Japan is reluctant to admit guilt. Japan has admitted guilt and they have done so for decades now. They have apologized to Burma, Korea, China, Australia, the United States, etc. And they have admitted to and apologized for atrocities such as the Nanking Massacre, the sneak attack on Pearl Harbor, their poor treatment of POWs, imperialism, etc. And they have acknowledged Unit 731 as well, the reason why they havent gone extensive with their apologies to Unit 731 (and in my opinion the reason why it doesnt get as much attention as it should) is because unlike Nazi human experimentation, the actions committed by Unit 731 werent very well documented and what little documentation there was, got destroyed. The only evidence we have of Unit 731 is testimonies of those involved and their victims. And finally, with the controversy with the text books that glossed over Japans atrocities, those books are essentially shunned by Japanese public schools and no credible school has accepted them (thus making the Chinese/Korean reaction, totally overblown).
And Japanese society has accepted war guilt as well. Japans culture is actually very pacifist as a result of their recognition of Japans imperialist past and the crimes their government committed. The people actually celebrate Article 9 of the Japanese Constitution and the majority of Japanese people do not want to see it done away with. Japanese academia is more than willing and fully embraces teaching their students about Japans war crimes. Now there are things that Japan could do better with their apology efforts such as Japanese politicians not visiting shrines that are dedicated to their war dead, their education boards not approving poor history books, and finding better ways to make up for Unit 731, but to say that Japans efforts in history education are lacking and that theyre reluctant to admit guilt is just dead wrong.
Now onto the second part, how war guilt is perceived by Japan and Germany and why it seems that Germany accepts more guilt than Japan does. There are two reasons for this and neither one of them have anything to do with race like youre implying.
The first reason is the easiest to explain, so I might as well just get it out of the way because its an incredibly simple reason: Germany started World War II. Even though Japan was attacking China since 1931 and went all out on China in 1937, historians pinpoint the start of World War II with Germanys invasion of Poland in 1939. And the Allies, rightfully I might add, saw Germany as the bigger threat that needed to be dealt with first. So when taking into account that even the Germans accept that they started a war that killed over 70 million people and were seen as the major belligerent, theyre going to feel guilty about that.
The second reason is much more complex to where we now need to look into Cold War politics and the Allied occupational policies of Germany and Japan.
When Germany was occupied, it was divided up between four administrative zones governed by the militaries of the United States, United Kingdom, France, and the Soviet Union. This is knowledge that Im more than certain that youre familiar with. However, what most people really dont look into is how the Allies were divided in that occupation.
The United States and United Kingdom were actually really conciliatory towards Germany. They saw occupation as an opportunity to rebuild Germany by punishing those responsible in the Nazi regime (the Nuremberg Trials), rebuild its government to prevent the reemergence of Nazi-styled authoritarianism, and restoring its economy to where it is a strong, active, vibrant and responsible member of the international community that would be a reliable trading partner for American and British commerce. And when the Cold War was brewing, the Americans and British saw Germany as a reliable ally in the fight against international Communism. The United States and United Kingdom, were willing to let bygones be bygones with Germany.
France and the Soviet Union on the other hand saw occupation as an opportunity to punish Germany. The French were humiliated with their easy defeat at the hands of the Nazis and the Soviets suffered the most casualties in World War II. Add in the fact that the French and Russians didnt fare much better in previous wars (World War I and the Franco-Prussian War) against Germany either. They had no desire to see a revived Germany and wanted to see a Germany that was weak, humiliated, and severely punished.
And then came the division of Germany with the Soviets backing the Communist dominated German Democratic Republic (East Germany) and the Western powers backing the Federal Republic of Germany (West Germany). The American and British zones were merged into the Bizone in 1947, the French however, didnt merge their zone in the united military administration until 1949. The reason why the French didnt join to form the Trizone two years later, was because of different views the French had with the occupation than the British and the Americans.
The French had significant leverage in negotiating against the Americans in regards to various Cold War policies. Because the Soviet Union was seen as the victor of World War II and the Great Depression severely damaged the reputation of capitalism, the French Communist Party was gaining some serious traction in France to the point where it looked like France was on the verge of succumbing to Communism through democratic means. This was unacceptable because France was seen as a vital ally to the Americans and British due to Frances geographic location (any expected liberation of Europe from the Soviets in a potential NATO/Warsaw Pact War was going to originate from France). Thus France, which had extremely nationalist tendencies following World War II thanks to Charles de Gaulle, wasnt going to let the United States and United Kingdom do things that were politically unacceptable to both the French government and French people such as fully rebuilding Germany economically and militarily. In order to get the French onboard (to accept many things such as the unification of rebuilt West Germany, the European Defence Community, etc.), the Americans and British had to give in to French demands such as not rearming Germany, actually punishing Germany, and weaken Germanys economic clout (a reason why organizations such as the European Coal and Steel Community were formed). On a side note that is pretty much unrelated, French leverage against the United States is actually the exact same reason why the United States supported French efforts in French Indochina following World War II, even though the United States was fundamentally opposed to colonialism.
French and Soviet efforts are pretty much why German culture pretty much accepts a lot of the guilt. And the Americans and British had no choice but to go along with it and support it in order to keep France content and secure in the non-Communist bloc.
Now lets move onto the Allied occupation of Japan. Like with Germany, the United States and United Kingdom had the same occupational objectives with Japan: punish those responsible (the Tokyo Trials), rebuild the government to prevent the reemergence of militaristic authoritarianism, rebuild the economy to make Japan a reliable trading partner for the United States and United Kingdom, and make Japan a reliable ally against international Communism. Unlike Germany though, there wasnt France and the Soviet Union getting in the way. The occupation of Japan was completely run by the United States with assistance from the British Commonwealth (United Kingdom, Australia, New Zealand, and India). The United States had no desire to punish the people of Japan like what France and the Soviet Union wanted to do to Germany and its people. Just like how they wanted to run the occupation of Germany, even though Americans were angry over Pearl Harbor, the United States government was willing to let bygones be bygones with Japan and move forward to a prosperous future together.
If Japan were occupied the way Germany was (the Franco-Soviet way), wed probably see Japan acting the same way Germany does in regards to their war crimes. And vice versa, if Germany was treated the same way Japan was (i.e. the Anglo-American way), Germany would probably be acting the way Japan is in regards to war guilt.
