Siege of Ulsan The Siege of Ulsan ( ) was an unsuccessful Korean and Ming Chinese attempt to capture Ulsan Castle from the Japan ese late during the Japanese Invasion of Korea ( Imjin War ) . Korean and Chinese allied forces suffered heavy losses during the siege , and the allied forces were ultimately withdrawn when the garrison sallied forth with the arrival of a relief force . First Siege of Ulsan . In 1597 , the second phase of the Japanese invasion of Korea was launched . After limited progress on land and several naval defeats , Japanese troops withdrew to the southern Gyeongsang province , in which they had set up a defensive perimetre . Without provisions and reinforcements , the Japanese forces had to remain in safety and security of the coastal fortresses ( known as wajō ) that they controlled . The Japanese commander Katō Kiyomasa had his army stationed in Ulsan , where he had his troops construct a castle . Commanders Yang Hao and Ma Gui led an army of 44 , 000 Ming troops , and Commander Gwon Yul led an army of 11 , 500 Korean tropps in a first assault on January 29 , 1598 . They caught the Japanese army unawared and still encamped , for the large part , outside of Ulsan ' s unfinished castle walls . The Japanese managed to drive off the attack and withdrew into the castle , but lost 500 men in the process . A total of around 55 , 000 troops with the help of singijeon s and hwacha s then besieged the fortress . The allied force made several assaults on the castle , but all attempts were repulsed by concentrated gun fire . However , the Japanese suffered heavily as well , with more than 600 men being killed and numerous more wounded . By the tenth day of the siege , the Japanese garrison was on verge of capitulating because of hunger and cold , but reinforcements under the overall command of Mōri Hidemoto came across the river to aid the besieged fortress , threatening the rear of the Chinese and Korean troops . The Ming commander Ma Gui began to realize the dangerous position of the allied forces , and late on January 3 decided to call off the attack and pull out of the area before the situation deteriorated any further . However , the calculated retreat quickly broke down and turned into a chaotic rout . The hasty and sudden timing , the heavy rain , the lack of discipline among the troops , and the quickly approaching Japanese forces all contributed to panic . In addition , the chief administrator present at the battle , Yang Hao ; left ahead of the troops , which only strengthened the impression that the intended calculated withdrawal was really a chaotic rout . With the advance of the relief force imminent , and seeing the disorganized withdrawal of the besieging force , the besieged Japanese garrison sallied forth and made a joint attack with the relief force . The allied forces retreated from Ulsan , and the siege of the fortress was suspended . After the defeat , in May , 1598 , the Ming government called General Yang Hao back and sent another army of about 20 , 000 men led by Liu Ting and a navy of about 13 , 000 men and 500 battleships led by Chen Lin and Deng Zilong to Korea . Second Siege of Ulsan . On September 22 , 1598 , Korean and Chinese allied forces made a second attack against Japanese forces at Ulsan . The alliance army formation was led by Commander Ma Gui , leading an army of 24 , 000 Chinese . An army of 5 , 500 Koreans was led by general Kim Eung - seo . Korean and Ming allied forces failed to take the Ulsan Japanese Castle , but unlike the first siege , managed to withdraw in good order .