The Koreans hate em. The Japanese took young Korean ladies and forced them to be camp prostitutes. If the girls got a disease or pregnant they would put a rifle inside them and shoot.
I spoke with an old man who had been on a japanese work crew. The supervisor died from a lead infection (shot) and then replacement refused the job and died the same way. So when they asked this guy if he wanted the job he took it.
The reason why: the Japanese do not teach anything about the history of the run-up to WW2 and the Pacific War in their schools. Older Japanese that lived through the war do not speak of it. It is like a 20-year national collective amnesia that afflicts the country.
When Clint Eastwood filmed “Letters from Iwo Jima”, he used actors from Japan. In order to portray Imperial Army soldiers accurately, the actors had to learn history they were not taught. They were dumbfounded to learn what Japan had done. They were very sobered by it and many realized that the bombings of Hiroshima and Nagasaki were the only way to end the slaughter.
The Japanese have been one of the most racist races on the planet.
Yes, the Koreans hate them and the Japanese thought the Koreans and Chinese less than human and treated them that way.
Everybody in Asia hates Japan as an entity, though they may have good business or personal relationships with Japanese companies or individuals. If a China-Japan war ever breaks out it doesn't matter what treaties these countries have with the USA - every one of them is going to support China.
My wife's grandmother survived the occupation of Singapore - to this day she hates everything Japanese...except sushi. :)