Sun Jin's speech: "Koguryo is the history of China, because the main part of Koguryo took place in China. Today, two-thirds of the original Koguryo territory is in China, when three-quarters of Koguryo residents surrendered to China. " "In most of Koguryo's history, Koguryo has always belonged to the Central Plains. Although South Korea advocated that Koguryo's history should be inherited by Silla from the process of "unifying the three Koreas" (Silla reunifying the Three Kingdoms). But Goguryeo does not belong to' Three Koreas'. The historical fact is that the Tang Dynasty merged Koguryo and Silla merged Baekje. "