In the midst of these vicissitudes the king appointed Chöng Se-un as general-in-chief of all the Koryŭ forces. He was a wise and loyal man and was ever thinking of ways and means of checkmating the invaders. He advised the king to send out a general letter encouraging the people and calling all the soldiers to rally to the defense of the country. The officials were also encouraged and made to feel that their utmost endeavors must be put forth in the good cause. The generals were all exhorted to do their best and were threatened with death in case they proved unfaithful. So the campaign was opened. The savages had looted all the towns about Song-do and had taken Wŭn-ju and killed its prefect. They also went north to An-byŭn in Ham-gyŭng Province where the people pretended to surrender, but, having gotten their conquerors intoxicated, they fell upon and killed them. The same tactics were tried in Kang-wha with equal success. Gen. Chöng Se-un now appeared before Song-do with 200,000 troops. These figures must surely be an exaggeration for we can hardly suppose Koryŭ able at that time to put that number of men in the field. Snow and rain added to the difficulties of the situation. A spy returned and said that the troops of the enemy were massed inside the South Gate and that if a picked body of men could gain entrance somewhere and attack them from behind they could be easily overcome. At the dead of night a picked body of horsemen gained admittance somewhere in the rear of the city and fell with fury upon the garrison. At the same time the main body advanced to attack the South Gate. The savages, not knowing the size of the attacking force and being surprised from behind were thrown into confusion and attempted to run away. Gen. Yi T‘ă-jo distinguished himself by pursuing and capturing Kwan Sŭn-săng the leader of the hostile force. In this stampede the routed savages trod on and killed each other by hundreds. In the center of Song-do the dead were piled in heaps. It is said, though it must be an exaggeration, that 100,000 men perished miserably on that night. As a result of this battle several Mongol seals which the savages had taken in previous fights with the imperial armies, were recovered. Some of the generals advised that a remnant of the enemy be spared; so the Sung-in and T‘an-hyŭng gates were thrown open and Pa Tu-ban and his remaining followers hastened out and made for the Yalu River.