In the autumn the Kitan army was again forced back across the border. The Koryŭ army had now grown to such proportions that the question of revenue became a very serious one and the officials found it necessary to suggest a change. They had been accustomed to “squeeze” a good proportion of the soldiers’ pay and now that there was danger of further change which would be only in the officials’ favor, the soldiers raised a disturbance, forced the palace gates, killed two of the leading officials and compelled the King to banish others. They saw to it that the military officials took precedence of civil officials. From that time on there was great friction between the military and civil factions, each trying to drive the other to the wall.
The next year, 1015, the Kitan people bridged the Yalu, built a wall at each end and successfully defended it from capture; but when they attempted to harry the adjoining country they were speedily driven back. The military faction had now obtained complete control at the capital. Swarms of incompetent men were foisted into office and things were going from bad to worse. The King was much dissatisfied at this condition of affairs and at some-one’s advice decided to sever the knot which he could not untie. He summoned all the leaders of the military faction to a great feast, and, when he had gotten them all intoxicated, had them cut down by men who had lain concealed in an adjoining chamber. In this way nineteen men were put out of the way and the military faction was driven to the wall.
Year by year the northern people tried to make headway against Koryŭ. The Sung dynasty was again and again appealed to but without success. Koryŭ was advised to make peace with Kitan on the best terms possible. The Kitan generals, Yu Pyul, Hăng Byŭn and Ya-yul Se-chang made raid after raid into Koryŭ territory with varying success. In 1016 Kitan scored a decisive victory at Kwak-ju where the Koryŭ forces were cut to pieces. Winter however sent them back to their northern haunts. The next year they came again and in the following year, 1018, Gen. So Son-ryŭng came with 100,000 men. The Koryŭ army was by this time in good order again and showed an aggregate of 200,000 men. They were led by General Kang Kam-ch‘an. When the battle was fought the latter used a new form of strategem. He caused a heavy dam to be constructed across a wooded valley and when a considerable body of water had accumulated behind it he drew the enemy into the valley below and then had the dam torn up; the escaping water rushed down the valley and swept away hundreds of the enemy and threw the rest into such a panic that they fell an easy prey to the superior numbers of the Koryŭ army. This was followed by two more victories for the Koryŭ arms.