I'm working on a TL where the Korean general Yun Gwan takes over southern Manchuria and Liaoning and Korea expands from there. I don't speak Korean, and can't find what the Koreans of Goguryeo and Balhae called these areas (Primorsky Krai, Liaoning & Sakhalin for those that haven't read the title), so I need help giving them Korean names. I have decided on Buyeo as a name for Korean South & Central Manchuria (named after an ancient Korean kingdom in the area).