[RealJames]

Just for the record on private teaching.
Before I started my business I was teaching 27 different private lessons a week at 3000y a lesson, most of them in Starbucks or at the student's home.

I lined up my gigs in different cities on different days, Saturday was Sannomiya, for 8 hours, buying a Starbucks drink every 2 hours. Sunday was Osaka in Umeda for 9 hours, same deal at the maru-biru.
The rest of the hours were in the evenings on weekdays, I had no weekday afternoon or morning classes at all.

But I netted about 290000y a month, way more than enough to cover cost of living and have fun. And that's on 27hrs of work, factor in transportation and that's about 35hrs away from home, that and it took me months to set things up nicely.

So, no, no one on a tourist visa would have time to set things up like that. But for the part-time workers and students out there, it's great.