Seriously my whole time in Japan, I did not run into ANY racial problems except! I was in Kawasaki about my 3rd to last day, and ran across some Uyoku, my Japanese friend was explaining to me what they were and some of them happened to be standing behind us and overheard.. They then began yelling in Japanese to my friend and my friend was like HURRY let's get in a taxi! Well after being chased by big black van's all the way to the internet cafe we were going to the guy that was originally standing behind us ran up to the taxi window when it stopped and went to punch me so when I got out I hit him a couple of times got back in the taxi and ran some more...

So advice, if you see the big black vans with flags hanging from them be quiet and just keep to yourself (If you cannot fight).