Gaogouli is the mandarin Chinese pronounciation of 高句麗 (縣 is widely translated as county in English). Certainly I use Gaogouli. Most of 1.3 billion Chinese People know that 高句麗 pronounces as Gaogouli (or mistake it as Gaojuli), but very few of us know Goguryeo. Are you Koreans going to force 1.3 billion Chinese to learn Goguryeo? -