The perception that the Joseon Navy played a crucial part in overcoming the national crisis during the Imjin War is dominant.
The naval forces in three provinces (Gyeongsando, Jeollado, and Chungcheongdo) forbade the Japanese army to advance from the sea, which greatly contributed to leading the war in favor of Joseon. However, the Gyeongsang Left Navy which was established and operated in the eastern part of Gyeongsang province with Busan at the center, was not able to function properly as it occupied by the Japanese forces from the beginning of the war.
This study investigates the military activities of the Gyeongsang Left Navy during the Imjin War. It is verified that the Gyeongsang Left Navy existed and carried out its duty clearly. Therefore, it is necessary to explore and examine the activities of the Gyeongsang Left Navy in order to review the naval history during the Imjin War.
A total of fourteen naval troops were in operation, including two Gwans (administrative land districts), and twelve Poes (naval forces administrative districts) in the Gyeongsang Left Navy right before the Imjin War. However, it was impossible to prevent the large-scale Japanese troops from invading Busan in the sea because the naval camps were dispersed widely around Busan. In the early phase of the war, therefore, the battles were mainly fought on the land. The commander of Gyeongsang Left Navy also participated in land battles, including Siege of Busan in which the general Jeong Bal fought hard, and Siege of Dadaepo in which Yun Heung-sin died in the last ditch for Joseon.
Then, the Gyeongsang Left Navy strengthened its offensive against the Japanese forces which remained in that area by the time the peace negotiation began. At this time, Kim Taeheo, the governor of Ulsan won a victory both in land battles and sea battles. In the meantime, Lee Suil, the commander of Gyeongsang Left Navy seized four enemy ships. During the period of the peace negotiation, the Joseon court sought for the measures such as the construction of panokseon (board roofed ship) to improve the combat power of the Gyeongsang Left Navy. However, the combat of the Gyeongsang Left Navy was only effective in a guerrilla warfare, and it was not able to overcome its numerical deficit against a large enemy.
This situation was the same even during Jeongyoojaeran, the second invasion. When Jeongyoojaeran broke out in January 1597, Gijang Hyeongam and the governor of Ulsan were not able to keep off the enemy and did nothing but reported the invasion of the enemy. However, during the first Siege of Ulsan, the Gyeongsang Left Navy was able to contribute some extent. Lee Unryong, the commander of Gyeongsang Left Navy, supervised the transportation of the provisions for Ming forces through the East Sea and actually exerted great influence in the battle with a small force. The Joseon court commanded the naval camps in the Gyeongsang Left Navy to move toward Busan. So the troops were intensively disposed in Busan.
In short, the Gyeongsang Left Navy carried out military activities in its own way although it was almost in the state of collapse in the early phase of the Imjin War. It could be considered that the Gyeongsang Left Navy did its utmost under the circumstances of that time even if the contribution was small compared to other regional navy.