[jasonbvr]

Don't you mean a visa run from Korea? I know a lot of teachers that come and get their working visas in Japan because Korea won't grant the visa when you are in Korea, but I have never heard of it being done the opposite way. Unless your working visa has expired, then I guess you would have to leave Japan and re-enter on a tourist permit. Or are you talking about your tourist permit expiring and needing to leave and come back to get another tourist permit?

I mean, your question isn't exactly clear. Work visas are granted within Japan as long as you apply for it. Even if it is about to expire, once you apply for renewal you are given a stamp showing your application is being processed.