My grandfather was a prisoner of Japan, captured at Singapore. Yes, badly treated, ended up in Taiwan. Japan of the 1930s was based on a fake culture. Modern Japan didn't exist until the 1880s and that was when Bushido was created. To create the modern state, Japanese soldiers had to be loyal to the Emperor, and not the Shogun. During WW1, Japan wanted to be part of the international order, as an equal. Western troops were admired; German POWs were treated as honourable soldiers. Some even decided to stay on in Japan. During the descent of the world order in the 1920s, the military decided they didn't like the International order, and the 19th Century code of Bushido was distorted to means all soldiers should have absolute loyalty to their master, and loyalty was valued more than life. So the POWs were genuinely seen as scum by the camp guard. The camp guards were mostly ethnic Koreans and Taiwanese Chinese, who were promised Japanese citizen if they were loyal soldiers. The brutality the POWs suffered was not particularly unusual when you have captors regarding you as subhuman. It doesn't take much for people you would assume were civilised to act uncivilised. Not only the Germans, but the Vietnamese. I'm sure many Americans enjoy holidays in modern day Vietnam, and probably can't fathom why the American POWs were treated so badly. Yugoslavia fell apart in just a couple of years, following fiery speeches at a Serbian union rally. Within a few years, the Serbs had turned sniping into a literal sport, and were running death camps straight out of WW2. We were genuinely shocked how such a thing could occur, among people we thought were pretty similar to us. And then in Iraq, some prison guards really let the side down in the way they treated prisoners at Abu Ghraib. In Afghanistan, it was long before reports of troops collecting body parts as trophies/proof of death, and of course reports of actual warcrimes (which some people coming out with excuses that we wouldn't have tolerated in WW2)/ We can all descend into the jungle pretty quickly; with the right conditioning. Russian soldiers, who might have been on holiday a few years earlier in Thailand, were laughing when cutting the knackers off Ukrainian POWs, despite the line from Russia that they were all really Russian.