After taking Pyeongyang, Li Rusong sent out Li Rubai, Zhang Shijue, and Yang Yuan with 8,000 troops. They retook Gaeseong on 19 February, and then the provinces of Hwanghae, Gyeonggi, and Gangweon. Next Li sent out scouting parties toward Hanseong, which Ryu Seong-ryong claimed had only some 10,000 Japanese troops. Yang Yuan, Li Rubai, and Zhang Shijue were given 2,000 men and ordered to take positions north of Hanseong. When reports that the Japanese were pulling out of Hanseong came in, Li himself decided to head out with his vanguard, leaving the artillery behind. He sent Li Ning and Zu Chengxun even further ahead.
Battle
The 3,000 strong advance force led by Zha Dashou, Zu Chengxun, and Go Eonbaek encountered a Japanese force of about 500 led by Jūji Den'emon. The Ming force retreated, luring Jūji into a bombardment and counterattack, killing 100. Jūji's remaining troops retreated and Tachibana Muneshigeattacked the Ming right flank with 2,000 troops. After suffering heavy losses due to a lack of cavalry, Tachibana retreated into the hills with 200 soldiers armed with firearms providing cover fire to prevent Ming forces from pursuing. Reinforcements led by Kobayakawa Takakage arrived at the battle, bringing Japanese forces to 15,000, forcing the Ming scouting party to retreat. At the same time, Li Rusong also arrived with 2,000 troops. Upon being informed of the Japanese presence by retreating soldiers, Li decided to take only half his men and charge ahead. Li Rusong's 1,000 cavalry encountered 3,000 troops under Awaya Kagenao occupying the hills around Byeokjegwan and fired on them with rockets. Awaya responded with matchlock fire but was unable to stop the rapid cavalry advance and was forced to retreat. However this led Li into a bowl shaped area where Inoue Kagesada brought 3,000 troops to attack his left flank and Awaya his front. Meanwhile 5,000 Japanese troops attacked the retreating Ming forces led by Zha Dashou. Inoue and Awaya's men were relieved of their positions by Kobayakawa and Tachibana, while they marched north to encircle the Ming forces. Seeing that the situation was lost, Li gave the orders to retreat. Yang Yuan joined the battle with the 1,000 cavalry Li had left behind, catching the Japanese in a pincer attack, allowing Li to retreat. Li Rusong's horse was shot out from under him and was almost killed, however Li Yousheng used his body as a shield to cover him. Li Rusong's brother, Li Rumei, then shot out the assailant's horse from under him. The battle lasted from late morning until noon. Finally Li Rusong was forced to retreat in the face of superior numbers.
Aftermath
The Japanese burned all the grass within the vicinity of Hanseong to deprive the Ming cavalry of fodder. According to Samuel Hawley, this led to the death of some 10,000 horses within a few days, but this number is disputed and possibly accounts for all horse casualties in the entire war. After the failure at Byeokjegwan, some Koreans called for the replacement of Li Rusong with Luo Shangzhi. Li also came under fire from his own subordinates. Wang Bidi accused him of denying his men adequate food and drink, directing battles from the rear, and refusing to give out the money or titles he had promised to those who first ascended the walls of Pyeongyang. Li deflected the blame towards Song Yingchang, a civil official.
Casualties
As with many battles in the Imjin war, the casualty figure is wildly different depending on the source. Li Rusong first reported a casualty figure of 264 against a kill of 167 enemies to the chief overseer Song Yingchang, though it was later blasted by other Ming officials back home of being faulty. An investigation concluded that the actual casualty figure was closer to the 2,000 range. The first Korean report on the battle relayed a story from a different Ming general that was not directly involved in the battle that the Ming lost 1,500 men while only killing a little more than a hundred foe, while the Japanese records seem to suggest that they lost 2,000-3,000 men while killing 6,000 men of the Ming force. One source in particular suggests that the Ming lost 20,000 men,. Given the nature of the battle and the maneuvers of both sides in the days and months after the battle, it could be estimated both sides lost between 2,000 to 5,000 men, though the Ming casualties were almost entirely among their elite retinues, which made the number more significant than it would appear.
Other controversies
Although the official version of the story was that Li Rusong and the Ming forces were misled by faulty Korean intelligence, some of the other Ming generals claimed that in fact it was Zha Dashou who misled Li and the other Ming forces. Zha thought that the Japanese forces were on the verge of collapse, and thus a fast and sudden advance on their position would cause them to pull out of Seoul, and as the vanguard of the group, he would gain the largest share of the glory. The generals cited that almost all of them were caught by surprise by Li's sudden departure the day before the battle, and scrambled to catch him. The battle and other disputes at Pyongyang and elsewhere led to an ever increasing friction between the Ming officers of different origins.
