sentences:  The battle erupted on January 19, 1950, when a detachment of Communist troops secretly climbed up the southern cliff of the mountain and dispersed the Nationalist guerrillas in a surprise attack.The defenders were overwhelmed by the rapid and decisive surprise attack and were completely demoralized; they abandoned their posts and began to flee.The commanders were unable to rally their troops for an effective counterattack and the guerrilla headquarters located in the Swallow Cave (Yanzidong, 燕子洞) fell, with a huge amount of weapons captured by the attacking enemy.