Zhang Xuan was ordering his troops to retreat immediately, but the withdrawal of his hundreds of thousands, or nearly a million troops, required a lot of time.
The undulating mountains in the Chu Territory are the best barriers for attack and defense, but also the greatest enemy of transportation and assembly. It takes time to get out of here, and a lot of time.
It was only at this moment that Zhang Xuan realized he couldn't just run away whenever he wanted. There was the 6th Group Army of the Tang Army in front of him, and his rear was no longer safe.
However, he still systematically arranged a retreat plan for the troops: the rear guard troops would immediately retreat toward the Shu Territory, dispersing as much as possible to avoid being harassed by the Tang Army's air forces.
Subsequently, his main forces would follow because the rear guard had already retreated, making the roads clear and allowing the main forces to retreat quickly.
