This sounds like a bad idea. If it's big in North America and Europe one of those competitors will be entering Korea soon. If they don't enter Korea there's a

This sounds like a bad idea. If it's big in North America and Europe one of those competitors will be entering Korea soon. If they don't enter Korea there's a reason for it that involves the specifics of that market. But you wouldn't know those specifics anyway because you know nothing of Korea. Unless you trust your cofounder like a brother, I wouldn't go for it.