No, you misunderstood again. Also, it's not a company job, as I said it's an academic one, it's settled and there's no job search involved. Assume position in country A ends on June 1, but position in country B (guaranteed) starts on Aug 1. There's a gap of 2 months inbetween. Work visa in country A ends on June 1, work visa in country B can only start on Aug 1. There's 2 months' worth of visa problem right in the middle.

Thanks for the response, but this doesn't really answer my question. I'm afraid I didn't phrase it clearly. My question was: is it possible to change status while in Japan on a tourist visa instead of getting a researcher's visa before arriving to Japan. If not, I would be forced to go from USA -> Country X -> Japan, move all my stuff twice instead of once, and go through all kinds of other trouble I don't want to go into details about. I would strongly prefer to avoid a double move.