I first heard of the Japanese occupation of China in a Bruce Lee movie called The Chinese Connection because I wanted to know what all the enmity was between the Chinese and Japanese in the Kung Fu movies I watched! So I read up on it and came across a book called : The Rape Of Nanking, which is about the atrocious behavior of the Japanese during the war! It was stomach churning. They were in some ways worst than the Germans.
Keep an eye out for books on the Korean "comfort women" as they also engaged in sex trafficking these women during the war and don't want to acknowledge that either.
The Japanese are not the innocent victims of the US hydrogen bombings they are often depicted as in American media and history is very complex. Everyone has good and horrible stories in their past!