Amakseong(阿莫城: The Amak castle), which was near Unbong(雲峰), Namweon(南原) in the present, was a traffic route and a route for attack which Baekje(百濟) needed to pass through in order to advance into Kyeongsangdo(慶尙道) of Silla(新羅) through the Sobaek mountains(小白山脈) in the territory of Gaya(加耶). Accordingly, Amakseong was a very important strategic point to both Baekje for advance and Silla for defense. Baekje started a battle to occupy this area in the 3rd of King Mu(602). This Amakseong battle was leaded by the nobles that controled Baekje’s political situation after King Wideok(威德: 554~598). However, Baekje was so disastrously defeated that 40 thousand infantrymen and cavalry soldiers were killed. This serious defeat caused King Mu(武), instead of the nobles who led the battle, to strengthen his royal authority.
On the grounds of his strengthened royal authority, King Mu managed to collapse Mosanseong(母山城=Amakseong: 616), and advance into Sokham(速含: Hamyang), Aengjam(櫻岑), Gijam(岐岑), Bongjam(烽岑), Gihyeon(旗懸), and Hyeolseong(穴柵), near the Nam River valley in the 25th of King Mu(624). King Mu continued to attack the middle of Nakdong River in Gyeongsangdo, and made a surprise attack for the capital of Silla in the 37th of King Mu(636). As a result, the battle in Amakseong gave King Mu an important chance to strengthen his royal authority in the domestic situation and was a basis to win a one-sided victory over Silla in the international one.