No, 90% of Gaoli residents were still in Manchuria and they built Balhae(Bohai to you), which bordered Bejing(Hence the sea next to Beijing is called Balhae Sea)
"Genghis Khan was the greatest Chinese conqueror of all time" - SinoChallenger
"
" - All the non-mainlanders around the world.
And the final one being PyeongYang for the last 200 years. The residents of PyeongYang fled 100 km south, and then rebuild their country and named it, guess what? Koryo(Gaoli to you).
More like China would have lost a chunk of Manchuria.
Anyhow, calling Koreans Gaoli Banzi and claiming the ownership of Gaoli is incompatible and contradictory. But then again, nothing that Chinese claim makes any sense and is simply laughed at outside of China.