I wanted to chip in here since I work within IT myself (not in Japan).

There is a few things you need to be aware of if you want to work IT (or most other jobs in Japan as a foreigner).

1. Get work experience in the field you want to work in, work in your own country for at least a few years and get some experience within the field. If you are fresh out of school you might get lucky but its not likely. (I say this because I am in the same situation and Japanese natives working in the industry has told me this.)

2. Learn Japanese (and learn it well). You need to be able to communicate fluently in the language. As I have learned when I was in Japan was that almost no one speak English and you really do get a sense of if you want to live in Japan (at least outside of Tokyo) you need to learn Japanese. This is especially important if you want to work outside the field of teaching English as a TA.

Good luck onwards and stay positive and you will end up where you want to be eventually.