What you're saying is very true and I was/am pretty aware of it. In fact, when I was in Japan, it was right during some heightened tension regarding some UN stuff or another. I'm also very very aware of the animosity between Asian countries, as (you probably know, but) it's not one-directional -- China hates Japan and (to a lesser degree) Korea, Korea hates Japan and China, and Japan hates Korea as well.
The reason I said "Maybe it was because I'm Asian and they can't tell the difference before I open my mouth" is because really, despite many American Asians' abilities to tell each other apart, I found that for the most part in Japan people could not notice that I (and some of the friends I was with) were Chinese/Korean. When I remained mute or spoke crappy Japanese, they just treated me like I was stupid or uneducated (which wasn't that bad -- which is where some of my previous comments about that came from).
I made a point when I was there to not tell people I'm Chinese, but in the cases when I did, some people were surprised and had thought I was an American-born Japanese person (some also thought I was Korean and other random ethnicities, but that's besides the point).
I guess I didn't get the feeling of stupid foreigner syndrome because I was with Japanese kids as well as my friends all the time -- the only times when we were alone was when we were touring shrines and temples in Kyoto and Nara and there were enough obviously foreign tourists there to keep the attention away from us.
I'll also make the note that we did have a white guy and a black guy in our group, and they were more like celebrities than anything else. When we were at this huge expo (I forgot what it was called), a number of girls came up to us to take pictures with them. Moreover when we decided to buy beer, the store clerk didn't ask questions or for an ID when faced with our friends haha.
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