My guess? It was a response to hundreds of years of Chineese brutalism.

The short answer is there is long history of China attempting to invade and conquer Japan thousands of years old) and their weren't always very friendly either.

Much of it is exaggeration. Like the 'rape of Nanking' is entirely based on the testimony of a single guy, John Rabe, who although he was German, was employed by the Chinese government. Lying in favor of his employer. Wouldn't be the first time someone does that.

The Japanese did much to raise the Chinese out of poverty. To this day, Manchuria remains more developed than the rest of China. The Japanese built so many railroads there that it can still be seen on a map of the .

Their feudal system treated their own peasantry badly. Non-Japanese are not considered human. Worse, surrender meant you're the lowest of the subhumans. Killing them or POWs was like killing varmints. Are you going to treat prisoners, who surrendered, better than your peasant class?

Japan and China have centuries of conflicts between them. Centuries of animosity certainly did not help.

The result is terrible medical experiments (example, microwaving POWs to death), forced death marches, slavery til death, rapings, practiced executions (like we practice hunting varmints), and so on.

Their history doesn't make their participation good or bad. It simply is their history and culture. Not all cultures are equal. It's important we weigh history through the lens of culture. At least enough to understand. Understanding doesn't, in of itself, make it right or wrong.

its called WAR

Why are you getting hung up? Tell whoever is asking that it's cultural differences and that condemning the Japanese is racist or bigoted and forcing a European moral code on the Japanese. If that doesn't work, tell them that it was considered normal amongst the eastern people.

So much could be considered an atrocity in war that it would be easy to go overboard either way. The Japanese and the Chinese have been bitter enemies for a very long time. Many centuries to be fair. Both cultures should be expected to be brutal as they are not Christian cultures, and even if they were, war is always brutal. But you can expect even more ruthlessness from who do not share Christian values at all.

This is a really complicated answer. Bottom line, the Japanese were extremely brutal to people in their occupied areas. That being said there was essentially a civil war going on in China at the same time and the nationalist government was also extremely brutal to the Chinese people, it is one of the things (probably the main reason) that the CCP gained power. There were also warlords (Chinese) and elements of the nationalist army that when taken by the Japanese actually worked for them in exchange for power. They were also brutal to the common people. There is a train of thought that if the U.S. hadn't tried to save the failing nationalist government in China that there would have been a reconciliation with the CCP and communism wouldn't have taken hold since the Russians couldn't support the communists ATT. Anyway there is more to it but its a really interesting story and actually intersects with McCarthy's witch hunts in the U.S. The best way to learn about this is to read post WWII books on international diplomacy which give credit to this argument without being tainted by current issues.

Because Chinese are bunch of faggots who we should have let Japan fuck over. Day one of Chinese liberation they started executing our troops. See John Birch for details.

Chinks are easy to hate. Someone with extensive time in China described them as "Autistic Turbo Jews on Steroids." Fuck em.