[Sangetsu]

A bento shop? Opening a business is risky (as you know), and restaurants (even bento-ya) are even more risky, with perhaps 2/3 failing within the first year.

If you are keen on opening up your own place, remember the first 3 rules of business: 1, location, 2, location, and 3, location. Nothing else is as important.

Theoretically, all ekaiwa position are part-time, and the income is actually not bad for the actual amount of work that you do. I wouldn't exactly call it "teaching", but it should be enough to sustain you while you establish your business, and possibly even finance it.

Good luck.