Who colonized North Korea?

Jizi (Gija) from Zhou dynasty colonized Korean peninsula first at 11th century BCE, after that, Emperor Wu of Han conquered Korean peninsula and established commandery called Lelang in Pyongyang in 108 BC. Korea was also conquered by Mongolian and governed by Yuan Dynasty for. Korea became totally independent form mainland China at 1895, but they colonized again by Japan during 1910-1945.