General Yi headed to Myongyong near the beginning of the strategically important Choryong pass to gather troops, but he had to travel further south to meet the troops assembled at the city of Daegu. There, General Yi moved all troops back to Sangju, except for the survivors of the Battle of Dongnae who were to be stationed as a rearguard at the Choryong pass. On June 4, General Yi deployed a force of less than 1,000 men on two small hills to face the approaching First Division. Assuming that the sight of rising smoke was from the burning of buildings by a nearby Japanese force, General Yi sent an officer to scout on horseback; however, as he neared a bridge, the officer was ambushed by Japanese musket fire from below the bridge, and was beheaded. The Korean troops, watching him fall, were greatly demoralized. Soon the Japanese began the Battle of Sangju with their arquebuses; the Koreans replied with their arrows, which fell short of their targets. The Japanese forces, having been divided into three, attacked the Korean lines from both the front and the two flanks; the battle ended with General Yi Il's retreat and 700 Korean casualties. General Yi Il then planned to use the Choryong pass, the only path through the western end of the Sobaek mountain range, to check the Japanese advance. However, another commander appointed by the Joseon government, Shin Rip, had arrived in the area with a cavalry division and moved 100,000 combined troops to the Chungju fortress located above the Choryong pass. Rather than face a siege, Shin Rip decided to fight a battle in the open fields of Tangeumdae, which he felt ideal for the deployment of his cavalry unit. Since the cavalry consisted mostly of new recruits, however, Shin Rip was concerned that his troops may easily be tempted to flee the battle. As a result, he felt the need to trap his forces in the triangular area formed by the convergence of the Talcheon and Han rivers in the shape of a "Y". This field, however, was dotted with flooded rice paddies and was generally not suitable for cavalry action. On June 5, 1592 the First Division of approximately 18,000 men led by Konishi Yukinaga left Sangju and reached an abandoned fortress at Mungyong by nightfall. The next day, the First Division arrived at Tangumdae in the early afternoon where they faced the Korean cavalry unit at the Battle of Chungju.