The terrain of Iron Wall Pass in the Central Region of Ji Kingdom is not particularly precipitous, its location not very important, and the garrison is not large. Initially, the Zhen Mountain Army dispatched a separate force intending to capture this city to guard against a flank attack by the Ji Army. Originally, the Zhen Mountain Army considered the city to be merely a motley crowd, easy to capture, but unexpectedly encountered desperate resistance, failing to take it.
Subsequently, the Zhen Mountain Army reinforced its numbers, and the Ji Kingdom reinforcements arrived. After bitter battles, the city remained uncaptured. Both sides continued to increase their troop numbers, engaging in fierce warfare for months, from winter to spring, culminating in a battle involving hundreds of thousands of troops.
