Regarding the successor state of Goguryeo

 Goguryeo is about whether it is a single nation.Goguryeo is a combination of tribes such as Malgal, Buyeo, Gaema Plateau indigenous people, Pyeongando Nakranggye, and Yoseoyodonggye (of course, I randomly classified them, but at least it's clear that Buyeo and Malgalgye are clearly divided).Of course, considering that the same nomadic people in Mongolia and Hun do not consider the national concept, it is presumed that they all thought they were the same Goguryeo people. The problem is after that.Balhae certainly has a lot of the legitimacy of Goguryeo.Then, as it collapsed by Khitan and some of the Goguryeo refugees were incorporated into Goryeo, Goryeo, which inherited Silla's legitimacy, insists on Goguryeo's legitimacy.Here, I wonder if Goryeo can claim to be the successor state of Goguryeo just by incorporating some of the Goguryeo refugees. Obviously, most Goguryeo refugees remained in Balhae, and if most of them were assimilated with the Yeojin, that is, if Goguryeo's descendants remained in the area, it could be said that the Geum Dynasty, which will be established in the future, gained legitimacy. However, what is so inconclusive is that Goguryeo occupied a large part of the Korean Peninsula, and it was Silla that destroyed them.Of course, since Japan destroyed Joseon, it cannot be said that Joseon history belongs to Japan, but Goguryeo residents were more hostile to the party than Silla, and thus took the lead in helping Silla to drive out the party.In other words, I think that the nationalist(?) who founded Balhae as above and opposed Silla and a kind of pro-Sinra faction (an ancient version of pro-Japanese group) who joined hands with Silla were divided. If Silla and Goryeo are the enemies of the nationalist world, there is no justification for pro-Sinra who cooperated with them (a kind of traitor), and if Goguryeo and Silla were enemies, wouldn't it be said that they were absorbed by Korea University?There is an argument that In summary, Goguryeo's legitimacy and succession state seem to be a difficult issue to be considered as a national concept, and it would be difficult to argue that Goguryeo is Korean history or Manchuria's history unless there is data to clarify the relationship between Balhae, Silla, Goguryeo, Silla, and Yeojin.Therefore, I think that the national genealogy - from Gojoseon to the Three Kingdoms to Joseon - is a narrow claim excluding Manchurians, and it is necessary to focus on and re-establish relations between Manchuria and the Korean Peninsula before considering this national genealogy.