@Sam_Arcade
Well, Knowing Japan's education system out-right not educating their children about their country's various war crimes during the war, its more likely that he doesn't know about it. If he does know about it, then it's pretty clear from the next chapter that Japan just wants the empires resources. If the empire can't pay up 500 million in amount of the currency (which they can't) despite only doing minor amounts of damage, then they will have to give them mines for materials, no reason was given why they needed these mines in specific other than the fact that they want resources for themselves. Their doing what they did in WW2, just using different methods. They are also forcing the Empire to sign the treaty, they can't say no.
I'm also making fun of the author's jingoistic views of outright trying to deny Japan commit crimes. In the first few chapters, he has one of the characters say "Might we Japanese do the same thing?" when talking about the various atrocities other countries did. That sorta proves that the author is denying Japan ever did crimes.