From New World Encyclopedia
Unification Aspects:

Balhae stands in the direct line of empires that trace their origin in Gojoseon and the mythical founder of Korea in 2333 B.C.E., Dangun. The line from the legendary founder, Gija (1222 B.C.E.) also dovetails into the history of Balhae. Although archaeologists in South Korea have emphasized the beginning of Korea from the Neolithic people living on the Korean Peninsula, the myths, legends, and histories coming out of northern Korea suggest that the origin of the Korean people began in the Gojoseon, Goguryeo, Balhae line of empires.

Most likely, both are true. The Neolithic peoples gave birth to Koreans in the southern peninsula while people immigrating from China gave birth to civilization in northern Korea. In a sense, Korea developed almost as two separate people until the establishment of Goryeo in 932 C.E. From that time, the northern and southern peoples of Korea merged into one unified empire creating one of the most, if not the most, ethically homogeneous people in the world.

Dae Jo-young founded Balhae, first called Jin, out of the northern remnants of the fallen kingdom of Goguryeo, defeated by the allied forces of Tang China and the Unified Silla dynasty from the south in 668 B.C.E. Tang claimed northern portions of Goguryeo while Unified Silla claimed southern portions. Much territory remained unclaimed by either, leaving Dae to establish the new kingdom of Balhae. Balhae existed as a kingdom coequal with Unified Silla, establishing a civilization waiting for archeologists' digs following the opening reunification of Korea in the future. The influence of China upon Korean civilization came more powerfully through Balhae than through the Three Kingdoms and Unified Silla.

Balhae and Unified Silla fell around the same time during the early 900s. Unified Silla fell to the armies of the new dynasty Goryeo while Balhae fell to the Khitans who renamed Balhae Dongdan. Many of Balhae's aristocratic class fled to the new state of Goryeo leaving much of Balhae to the Khitans. As the map at the beginning of the article shows, almost all of Balhae's territory now lay in the domain of China.

Unification Aspects is designed to relate the subject of this article to Unification Thought and to aid
teachers and researchers who wish to further pursue these topics from a unification perspective.