The region where China and Russia meet in Heilongjiang Province was home to Sushen, an ancient chieftain-state of the Zhou Dynasty. It was called Mohe during the Sui and early Tang dynasties, with dozens of tributes spread across the Heilongjiang and Songhuajiang river areas. Mohe was later divided into the northern section, which became part of Heishui, and the southern section, which was incorporated into Sumo. After the downfall of Goguryeo, Chief Da Zuorong took the initiative to establish a united front with the Sumo section of Mohe and the remnants of Goguryeo.