Korean Tourist Visa

I'm heading to Korea soon to spend time with my girlfriend. I was hoping to stay for more than three months, but the limit without a visa is only 90 days. Obviously I hope to be with her as much as possible whilst I finish studying.

Would it be possible (and is it generally allowed) to stay in Korea for 90 days, then fly to somewhere like Japan for a week, and after that week fly back to Korea for another 90 days? Or will this be picked up by the immigration offices there, and then get me kicked out of the country/refused entry?

Thanks for your help!
Asked Sep 23, 2015

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