Coming from China. ESL job before arrival?

Hi
UK native speaking ESL teacher.
Many time question poster.
Just started working in China as an ESL teacher.
I've done some research about getting an ESL job in Japan next year but I see a problem.
From what I've seen, the big companies who sponsor visas like Aeon hire from native speaking countries where they hold seminars and interviews, and the small companies don't sponsor visas so you have to already be in Japan with a valid visa (i.e. changing between jobs in Japan or married to a Japanese person).
I don't want to spend half my savings going back to the UK just to apply for a job at one of the big companies only to come all the way back to Asia.
Any native speakers been hired while living abroad to work in Japan?
Any advice?

All the big companies have in-country hiring systems too. I imagine that if you're able to come to Tokyo or Osaka for an interview, then I think it won't be a problem. It may be a bigger problem getting a visa, since normally that should be handled by the Japanese Embassy in London.

I was thinking that. The visa is the problem. With my experience I know I can get a job, but it seems I can't get a visa unless I'm in the UK. I guess I'll just have to save enough money to come to Japan for a week and do interviews before I move there and see what happens.