I would recommend you to really look into the Japanese's doings during World War 2, how they oppressed the whole of Asia. Then, only comment on why Chinese is still resentful towards Japan to this day. Thank you :)
Plus, a manga does not mean anything when it only portrays Chinese culture to a T, it's irrelevant to talk about Chinese sentiment in a manga comment section.
Please, don't paternise me. The Chinese government is every inch as horrible to its own people as the Japanese ever were. But by enticing them toward Japan, they take away the attention of the people to what they actually do themselves.
And why would a Japanese manga be unintitled to talk about Chinese culture? There are thousands of novels and comics and theatre plays that talk about an other culture. Why not? Ever heard Danemark complain about Shakespeare's Hamlet?
I totaly agree with ? number 1, up top here. The mangaka has captured the atmosphere that you can find in movies like "Farewell to my concubine". It's sad, really, that the Chinese public opinion is still so hostile towards Japan (enticed by the government...), while the Japanese so obviously still love the Chinese culture dearly.