This study aim to research the strategy and historical meaning of the Hansung Engagement in 475 because this Engagement changed the domain of East Asia. Therefore, the conclusion of this study is as follows.
First, Koguryŏ was the supreme power of the Far East in the 5th century. Koguryŏ had moved her capital to Pyongyang in 427 because of the success of the oriented to west policy in the northwest. So Paekche organized a anti-Koguryŏ Federation with Silla, Gaya and Wa(倭). Therefore, Paekche took the leadership of the anti-Koguryŏ Federation. Paekche had taken the diplomacy measure to China. However, Paekche could not obtain the practical effect. And Koguryŏ also took the diplomacy measure to China. Therefore, China did not want to make war with Koguryŏ. On the contrary, Koguryŏ wanted to assault the Hansung area to protect the attack of the anti-Koguryŏ Federation.
Second, Koguryŏ made the project to attack the Hansung area. And Koguryŏ made the strategy plan on attacking the Hansung area step by step. At first, Kogurea secured the strategic positions: Horokoru-castle walls(瓠蘆古壘城), Acha-castle walls(阿且山城), Chilchung-castle walls(七重城), and Monchon-castle walls(夢村土城).
Third, Koguryŏ used strategic positions rather than the road. Koguryŏ had an aim to use the strategic positions to secure the Han-river after the Hansung Engagement. If Koguryŏ had lost these strategic positions, she would have lost the territory. And the oriented to south policy of Koguryŏ brought down the power of the Koguryŏ in East Asia. Therefore, Tang-dynasty was born in China. After that, Tang-china and Silla attacked Paekche and Koguryŏ.
The Hansung Engagement of Koguryŏ played a decisive role in changing the domain of East Asia.