Hi there,
If you'd like to learn more about the requirements needed to teach in Japan then you may like to take a look at section 7 of our free e-book called TEFL Uncovered.

You can view it here:
http://www.onlinetefl.com/contact-tefl-team/tefl-ebook.html?source=chalkboard

With regards to reputable jobs, it's always advisable to do some research first. For example; can the employer put you in touch with previous TEFL teacher? Has anyone on Chalkboard had experiences with them? Can they provide a valid address?

Hope this helps!