I want to have a job in Japan

[groenschoen]

I was wondering, since most foreigners become English teachers:

1) Do you need to be a native speaker to become an English teacher? Cause I'm not, though you won't notice talking to me. I even have an American accent...

2) I allways wanted to become a teacher, but I'm a math student and in 5 years I'll have a Master in Mathematics. Do you think I could become a math teacher in Japan?