The first nine months (Apr. 13, 1592-Jan. 9, 1593) of Hideyosh"s invasion of Korea, during which the outcome of the war was almost determined, starkly exposed the sheer imbalance of military power between Joseon and Japan. The inept response of the governmental forces of Joseon toward the invasion and the blitz tactics of the Japanese forces, supported by its overwhelming military power, are cited as the decisive factors in the outcome of the war. The ineptitude of the government forces of Joseon resulted from the following three factors.
First, the Joseon government made a mistake in war preparations. The government was not aware that the Japanese infantry was armed with the most advanced firearms at that time. Because of this ignorance, the defense strategy of Joseon relied upon the traditional cavalry tactics, and, as a result, the government troops suffered crushing defeats in the combats in Sangju and Chungju.
Second, the government insisted on such outdated regimentation system as Bubyeong-je ( , "all peasants convertible into soldiers" 府兵制institution), based on the Byeong-Nong ilchi-je (兵農一致制, "all farmers are to become soldiers in times of needs") system, and also Je"seung Bang"nyak-beop (制勝方略法, military strategies for victory) protocols. The government forces were composed of non-regular combatants, recruited as servicemen only at war times. Upon the order to join the army at the beginning of the war, they would avoid being recruited as much as they could, and even attempted to flee when they were called to arms. In addition, the commanding officers dispatched from the central government under the Je"seung Bang"nyak-beop protocols had little information of the troops they were in charge of. For this reason, they experienced extreme difficulties in communicating with their servicemen. In addition, their rigid manner of operating the armed troops and tactical misjudgments led to repeated defeats.
Third, the central government was reeling from extreme strife among political factions, which resulted in inconsistent war policies. It was King Seonjo who should be held responsible for the total disarray. Even though the government got down to the war preparations three to four years before 1592 when the war began, it could not make any desired results, due to the chronic factional strife. There was no change in the internal political strife even during the war. Therefore, the war policies were administered not by a systematic scheme, but by personal networks of the bureaucrats in the central government. In the end, a ‘sense of resignation’ prevailed over the political circle of Joseon, which had no other means than prayer.