similar political and economic systems
So Communism and Capitalism are similar? Well I'll be.
A Parliamentary Monarchy and a Communist run regime are similar as well 'eh?
Anywho, I think you see at what everyone's saying. The only real similarities between the two are the writing systems and some stylistic things.
China isnt exactly a communist country or economy. They like to think it is.
I dont want to get into the debate about the cultures being the same or not because I'm not very knowledgable on the history of both countries. What I can say is that culture clashes or similarities isnt unique to those two countries, and a lot of anger from either side comes from what their military and governments done. Nanjing is probably the big one however it should be noted that the Chinese government is as ruthless to its own people as the Japanese military was to the Chinese, so we could say most of it also comes from nationalism.
Japanese are proud of their country, equally Chinese are proud of their country, yet neither will know the full extent of what each country has done; I've read plenty of times (and to the chinese governments anger) that the Japanese history education doesnt include much about what they done in China, and equally the Chinese have done a good job internally at covering up what happened at say, Tiananmen square (i remember seeing a documentary and apparently not many youths know the real score on what happened).
Another example to stress this point; How many British know the real truth of what happened in Ireland when the Black and Tans where around? How many Americans know the full extent of Vietnam outside of media reports? How many Russians know the full extent of Chechnya? Not many because the general public do not do a lot of reading into these things nor are they taught the full story.