When Wang-gön heard of these atrocities, he hastened forward his troops and overtook the army of Kyŭn-whŭn in O-dong forest where a sharp engagement ensued. For some reason, whether it be because the soldiers of Kyŭn-whŭn were more familiar with the locality or because the Koryŭ soldiers were exhausted by their long forced march, the assault was unsuccessful and the Koryŭ forces withdrew. This was doubly unfortunate for it not only did not punish the ruffians for their atrocities at the Sil-la capital but it inspired them with confidence in their own power. Shortly after this Kyŭn-whŭn sent a letter to Wang-gön saying “I became Sil-la’s enemy because she sought aid from you. You have no cause for warring against me. It is like a dog chasing a rabbit; both are tired out to no purpose. It is like a king-fisher trying to catch a clam; when he thrusts his bill into the shell the clam closes it and he finds himself caught”. To this epistle Wang-gön replied “Your actions at the Sil-la capital are so outrageous that I cannot endure the thought of any compromise. Your present course will lead you to speedy ruin”.
Elated over his successful repulse of Wang-gön’s army, Kyŭn-whŭn took the field the following year, with a strong force, and was prepared to assume the offensive. He assaulted and took two Koryŭ fortresses and even, at one time, surrounded Wang-gön in Ch’ŭng-ju and caused him no little anxiety. In the battle which followed Kyŭn-whŭn lost three hundred men and was pushed back, thus freeing the king from an embarrassing position; but before the campaign was over Kyŭn-whŭn scored another victory by capturing the district of Ok-ch’ŭn. In his next campaign he was still successful, and Eui Fortress fell into his hands and he killed the general in charge. Here his successes ended, for Wang-gön awoke to the necessity of using strong measures against him. The following year Koryŭ forces inflicted a crushing defeat upon the southern leader, at An-dong. The fight had lasted all day and neither side had gained any advantage, but that night a picked band of Koryŭ men ascended Hog’s Head Mountain and made a rush down upon the unsuspecting camp of the enemy, causing a panic and a stampede in which eight thousand men were killed. Kyŭn-whŭn himself sought safety in flight. This seemed conclusive and all the countryside sent in their allegiance to the victors. A hundred and ten districts in eastern Korea came over to Wang-gön in a body. Dagelet Island, or Ul-leung as the Koreans call it, sent presents to Koryŭ.