In 383 AD, Former Qin Emperor Fu Jian assembled a massive army of 900,000 soldiers and marched south to attack the Eastern Jin dynasty. The Eastern Jin court dispatched General Xie Shi and vanguard Xie Xuan to lead 80,000 elite troops in defense.
Fu Jian, confident in his overwhelming numbers, gathered his forces along the Fei River east of Shouyang (modern Shou County, Anhui), waiting for reinforcements before launching an attack on the Jin army.
To achieve victory with fewer troops, Xie Xuan devised a plan and sent an envoy to the Qin camp, suggesting to the Qin vanguard, "Your army has set up camp by the Fei River, clearly intending a prolonged battle rather than a quick resolution. Would it not be better if you withdrew slightly, allowing my forces to cross the Fei River and engage in decisive battle?"
Within the Qin army, the generals debated the situation, with most arguing that holding the Fei River would trap the Jin forces on the far bank, allowing them to crush the Jin army once reinforcements arrived. They concluded, "We cannot accept their proposal to cross."
However, Fu Jian was too eager for victory and disagreed with his generals, saying, "If our army retreats just a little, when half of the Jin army has crossed the river and the other half is still crossing, we can charge with our elite cavalry and surely achieve a great victory!"
The Qin army then decided to retreat. Fu Jian had not anticipated that his forces were hastily assembled and lacked unified command; upon receiving the order to fall back, they mistakenly believed they had been defeated on the front lines and fled in panic.
Xie Xuan, seeing the enemy forces in full retreat, commanded his troops to swiftly cross the river and press the attack. As the Qin army fled, they discarded weapons and armor in utter chaos, with countless soldiers trampling each other to death. Those who managed to escape the Jin pursuit, hearing the howling wind and the cries of cranes along the way, believed the Jin army was still chasing them and fled desperately day and night. Thus, the Jin forces achieved a decisive victory at the Battle of the Fei River.
"The idiom 'Wind Sound, Crane Cry' refers to mistaking the sound of wind and the cries of cranes for enemy shouts, suspecting pursuers are coming, used to describe panic and extreme nervousness."
Source: *Book of Jin*, "Biography of Xie Xuan"
Meaning of the Idiom: Later, the Chinese idiom "风声鹤唳" came to describe how mistaking the sound of wind and the cries of cranes for enemy shouts, suspecting pursuers are coming, describes panic and extreme nervousness.