Tourist Visa Japan (Multiple entry)

Hi, I'll travel to Japan on the tenth of October and plan on leaving the 23d but I need to be in Seoul for business the 16th. I plan on flying into Seoul from Osaka in the morning and out of Seoul in the evening. As I need to attend a wedding the next day.

But to the main question: will I have to fill out the forms two times and will I get stamped two times or can I apply for a re-entry permit?

Thank you in advance