The prerequisite for that, according to [0], is "The Limited Stay Visa, or VITAS1, is a single-entry visa that foreigners may obtain for the purpose of investment, research, work and etc".
Fair enough, so it looks like he's got his KITAS. Bear in mind that's a significant hassle to get and can be quite costly with all the documentation needed. I have a friend who recently got his, as he needed to be the director of a company, and all up I believe it cost around USD$3500.