I would imagine that you will not get any obvious racism, but I`m sure there will be a lot of subtle racism. In my experience, I have come to the conclusion that people of the "Orient" consider themselves superior to "black" people, as do many other people from all over. But many Nigerians, Somalians, Ghanaians, Saudis, Arab Emirates, consider themselves superior to Europeans. So similarly, you may not find the Japanese very helpful or friendly towards you.

Second point for me though is also the question of your command of English, I know for example that in Nigeria, English is spoken as a first language, but it is not exactly English in my opinion, is it? Having watched a number of Nigerian films, I would describe it more as Pidgeon English, and I`m sure you realise that this is not the kind of English that Japanese students should be learning; I mean can you imagine a Japanese person talking Nigerian English...

"Ok, I`m going to meess(miss)my boss(bus)".

However if you speak the Queens English and you have the right credentials, I see no reason why you shouldn`t be able to earn a good salary. But you may have a little more difficulty convincing a school of this.

You have to ask yourself weather you can honestly educate these students, or are you just thinking about all the money you could earn.