Hello, I'm Japanese working English school in Tokyo.
First I shoud say, I can't use English well.

Is teaching English difficult? If it is difficult, is it cause of need to speak Japanese?

I think teaching English conversation is not so difficult, but to schedule lessons, you need to use Japanese, isn't it?

But many English speaker in Japan, they want to teach English, I think.

If someone manage schedule instead of you, do you want to teach English?

People like David Thayne (see rant about him at http://avery.morrow.name/blog/2012/02/david-a-thaynes-scam-on-the-japane/ ) make it more difficult for teachers by terrifying beginning learners of English of making even the smallest mistakes. If you don't ever try to form your own sentences despite knowing you might get something wrong, how are you supposed to even start learning a foreign language?

As for me, I know enough Japanese to deal with the scheduling myself, but I'm not a native English speaker. Therefore I'd probably have difficulties finding any English school willing to employ me.

Thank you for your reply.

Now our English teacher will change his occupation in the end of June. And our owner said that if we can't find new teacher, he will close school.
He wants to the new teacher who can arrange schedule and other management by himself only.
To find that teacher is so difficult. Now I think that we can't find and school will close.
But we don't leave our students.
So I think if someone can teach as freelance, and if we arrange schedule in Japanese, our students can continue lessons.

That sounds sensible, as long as the communication with the teacher about the schedules works fine. Best of luck finding a new teacher!

I see. Thank you very much.