拔帜易帜 — “Pull down the old banner and set up one's own banner”

After Han Xin was appointed a great general by Liu Bang, he led the Han army to conquer the states of Wei and Dai. Then, with the assistance of Zhang Er, he took tens of thousands of soldiers eastward through Jingxing Pass to attack the state of Zhao. King Zhao and his chief general Chen Yu gathered an army of two hundred thousand at Jingxing Pass to block their advance.

The strategist Li Zuo-che advised Chen Yu to give him thirty thousand troops to take a secret path, unexpectedly cutting off the Han army's logistical supplies and food. Meanwhile, Chen Yu's main army should not engage the Han forces head-on when they reached Jingxing. He believed that this strategy would allow them to capture Han Xin and Zhang Er's heads within ten days. However, Chen Yu was a scholar who disliked using cunning stratagems. He thought Han Xin's army consisted of only a few thousand men, who were extremely fatigued after marching a thousand li, and could be directly attacked. Therefore, he did not adopt Li Zuo-che's plan. Han Xin's subordinates, upon hearing this news, were overjoyed and confidently proceeded eastward to Jingxing.

When they reached a point thirty li from Jingxing Pass, Han Xin ordered a rest. In the middle of the night, he selected two thousand light cavalrymen, each carrying a red flag, to take a small path and hide behind the mountains at Jingxing Pass. He told them, "I will send another army to confront the Zhao forces and pretend to retreat. The Zhao army will surely pour out of their camp to pursue us. You must seize this opportunity to swiftly enter the Zhao camp, pull down their banners, and replace them with our Han army's red flags."

Next, Han Xin dispatched an army of ten thousand men, ordering them to form a battle array with their backs to a river. When the Zhao army saw the Han army arrayed in a formation most taboo in military strategy – with their backs to a river – they all laughed, believing the Han army had cut off their own retreat.

At dawn, Han Xin led this ten-thousand-strong army to advance towards Jingxing Pass. The Zhao army immediately opened their camp gates to engage them. After fighting for a while, Han Xin and Zhang Er ordered their Han soldiers to abandon their flags and drums and retreat towards the river. The Han soldiers, having retreated to the riverbank, could not fall back any further and were forced to fight desperately. At this moment, the two thousand Han soldiers hidden behind the mountains, seeing the Zhao camp unguarded, swiftly rushed in. They quickly pulled down the Zhao army's banners and replaced them with the Han army's red flags. Meanwhile, the Zhao soldiers fighting by the river, unable to gain victory against the Han soldiers' fierce resistance with their backs to the water, wanted to return to their camp. However, they saw only red Han flags there, leading them to believe that King Zhao had been captured by the Han army. Their morale instantly collapsed, and they scattered in panic.

Subsequently, the Han army attacked the Zhao forces from two sides. As a result, chief general Chen Yu was killed, and King Zhao was captured alive.