As a preliminary, a messenger was sent to Song-do to demand why the king had been put to death. The officials were thrown into a panic and hastened to send and envoy to Kitan to explain matters. He was held a prisoner by the emperor. The king sent again and again, ten envoys in all, but an ominous silence was the only answer. It appeared that something serious was about to happen, but just what it was could not be surmised. In order to be ready for any emergency, the king sent Generals Kang Cho and Yi Hyŭn-un to T‘ong-ju (now Sŭn-ch‘ŭn) in the north to guard against a sudden surprise.
Early in December the spell was broken and the watchers by the Yalu hurried in with the news that a cloud of Kitan warriors was already crossing the stream. The invading army 400,000 strong, so say the records, pushed forward and surrounded the Koryŭ forces at Heung-wha camp. When it was found, however, that they would stand their ground and fight, the invaders sent presents of silk and other valuables and advised them to surrender, and said “We liked the king whom Kang Cho killed, and we are determined to overthrow the murderer. You assist us in this. If not we will destroy you root and branch.” The reply was “We prefer to die rather than surrender.” Thereupon the enemy sent more costly presents still but the answer was the same. When it became plain that there was to be bloodshed before Koryŭ would come to terms, the Kitan emperor divided his immense army into two divisions, sending 200,000 men to the vicinity of Eui-ju and 200,000 to T‘ong-ju. Gen. Kang Cho cunningly disposed his little army between two creeks where he was protected on either flank. It is said that he had a species of battle chariot with swords attached to the axles of the wheels so that when they charged among the ranks of the enemy the latter were mown down. On this account the little Koryŭ army was at first successful. Then Gen. Kang Cho was seized by that common infatuation of fancied security and in the midst of the fighting he sat down in his pride and began playing a game of go-bang. A messenger hurried up with the news that the line of battle had been broken on the west and that the enemy were pouring in. Gen. Kang Cho laughed and said “Do not come to me with such an insignificant piece of news. Wait till they come in numbers worthy of my sword; then come and tell me.” Soon a messenger came saying that the Kitan forces were approaching in full column. Thereupon Gen. Kang arose and prepared for battle. While doing so the annals say that the spirit of the murdered king appeared before him and chided him for scorning the power of Kitan. He took off his helmet, and, bowing before the apparition, said “I have committed an offence worthy of death.” The Kitan soldiery rushed in and seized him. They bound him in a cart and took him away.