The Battle of Fei River or “Feishui”(淝水之战)was a battle in 383, where Fu Jiān (T.: 苻堅) of the Di Former Qin Empire was decisively defeated by the numerically inferior Chinese army of Eastern Jin. (The location of the battle, the Fei River, no longer exists, but is believed to have flowed through modern Lu'an, Anhui, near the Huai River). The battle is considered to be one of the most significant battles in the history of China. The aftermath of the battle includes the Former Qin empire falling into massive civil war and its eventual destruction, ensuring the survival of Eastern Jin and other Chinese regimes south of the Yangtze River (Chang Jiang).
The state of Former Qin, lead by ethnic Di (氐) tribesman, rose rapidly from a string of successes in the 350s. Fu Jiān, nephew of the founder Fu Jiàn, was a vigorous leader of tremendous drive and ambition. In 370 he conquered the state of Former Yan and in 373 seized modern Sichuan and Chongqing from Jin. In 379, the strategically important city of Xiangyang, gateway to the Middle Yangtze fell to Qin. By 381, he had conquered all of north China and was preparing for an invasion of the south.
In May of 383, a Jin army of 100,000 commanded by Huan Chong attempted to recover Xiangyang but was driven off by a Qin relief column of 50,000 men. In response, Fu Jiān ordered a general mobilization against Jin: 6 in 10 able men were conscripted, and 30,000 elite guards (羽林郎) were gathered. In August of 383, Fu Jiān sent his brother, Fu Rong the Duke of Yangping (who had opposed the campaign) with an army of 300,000 as the advance force. Later that month, Fu Jiān marched with his army of 270,000 cavalry and 600,000 infantry from Chang'an. In September, Fu Jiān reached Xiangcheng. Separate columns were to push downstream from Sichuan, but the main offensive would occur against the city of Shouchun on the Huai River. Emperor Xiaowu of Jin hurriedly made preparations for defense. He gave Huan Chong responsibility for the defense of the Middle Yangzi. The pressing defense of the Huai River was given to Xie Shi (謝石) and Xie Xuan (謝玄) and the elite 80,000-strong Beifu Army (北府兵). The prime minister Xie An oversaw overall strategy, and, while he lacked military abilities, he calmed the panicking officials and people by himself acting in a calming manner.
Former Qin Army
Fu Jiān's force was composed of many smaller armies levied from the conquered northern territories, along with cavalry drawn from the nomadic peoples of the north (the Xianbei and Xiongnu). Most men had little or no loyalty to the Former Qin, and many were forced to join, or joined only because of military rations and pay. Many battalions had problems following orders as instructed by their commanding officers. Fu was warned of the poor training of his heterogeneous army, but instead chose to rely on the vast number of men that made up the army saying "My army is so huge that if all the men throw their whips into the Yangtze, its flow will be stopped," (投鞭断流)
Xie Xuan's local army were well motivated to protect their homeland, and had a good local knowledge of the terrain - an advantage that would allow them to engage advance elements of the enemy and withdraw quickly
In October 383, the Former Qin forces under Fu Rong captured the important Jin city Shouyang (壽陽, in modern Lu'an, Anhui). Fu Jiān, seeing the possibility of achieving a quick victory, left his main force at Xiangcheng and led 8000 light cavalry to rendezvous with Fu Rong. Fu Jiān sent the captured Jin official Zhu Xu (朱序) as a messenger, to try to persuade Xie Shi to surrender. Instead, Zhu tipped Xie Shi to the fact that the entire Former Qin force had not arrived yet, and that he should try to defeat the advance Former Qin forces to cripple the Former Qin's campaign. Under Zhu's suggestion, Xie Xuan and Liu Laozhi (劉牢之) led 5,000 elite troops to engage the advance Former Qin force and scored a demoralizing victory, killing 15,000 men. Afterwards, Jin forces were lined up in a wide formation, to give an illusion that Jin forces can match Former Qin's manpower (草木皆兵). Because of the early minor defeats and the Jin formation, Fu Jiān overestimated the amount of Jin forces.
In November 383, the Former Qin troops set up camp west of the Fei River. The Jin forces stopped east of the Fei River and could not advance. Xie Xuan sent a messenger to Fu Rong, suggesting that the Former Qin forces retreat slightly west to allow Jin forces to cross the Fei River, so that the two armies could engage. Most Former Qin generals opposed, since reallocating such a large army was too complicated for the benefits, specially with so many poorly trained troops. But Fu Jiān overruled them, planning to attack the Jin forces as they were crossing the river, to seize a tactical advantage, as the Jin forces would be split in two. Fu Rong agreed, and he ordered a retreat.
The Jin's tactic of ambush and bribery now paid off. Many soldiers in the Former Qin army began to wonder why a sudden retreat order was given. Already retreat with a lowered morale, Zhu Xu raised a cry of "the Qin army has been defeated", the Former Qin army went into a panic and was routed, and Xie Xuan and other generals Xie Yan (謝琰) and Huan Yi (桓伊) crossed the river and launched a major assault. The "Qin is Defeated" rumor spread like wildfire, and chaos followed. Fu Rong tried to personally halt the retreat and reorganize his troops, but his horse suddenly fell, and he was killed by advancing Jin troops.
The Jin generals noticed the chaotic footprints and wheel marks, and declared that the Former Qin army was not in an organized retreat, but is indeed in total disarray. The Jin soldiers continued their pursuit, and the entire Former Qin force collapsed. A large amount of food and supplies were abandoned as Former Qin soldiers tried to escape with their lives. In the ensuing retreat and pursuit, in addition to famine and death from exposure to the elements, an estimate of 70-80% of the Former Qin force were killed.
Legend has it that, as Fu Jiān escapes, he screamed to the sky "天亡我也！", which means "The heaven has annihilated me!".
The Jin army defeated the overwhelming Former Qin army, with only minor casualties. The Jin army had routed most of the escaping soldiers of the Former Qin army, greatly weakening the pool of soldiers from which the Former Qin could draw from. Fu Jiān's forces were not able to be reorganized, even after he eventually withdrew to Luoyang under the protection of Murong Chui, whose 30,000-man army was one of the few which did not collapse.
Meanwhile, agrarian rebellions arose after news of the defeat at Fei River. Murong Chui used this opportunity to request Fu Jiān to permit him to try to lead an army to pressure the rebels in the eastern empire back into submission. Instead, Murong Chui himself rebelled in early 384, which started a chain reaction of many Xianbei and Qiang uprisings. The Former Qin capital Chang'an would fall in 385 to the Xianbei forces of Western Yan, and Fu Jiān himself would die later that year at the hands of his former general Yao Chang, the founder of Later Qin. While Former Qin would last until 394, it would never regain its power and glory. In addition, after the battle, Jin forces advanced to the Yellow river and recovered much of the Chinese heartland, forming a basis for Liu Yu's expeditions and the Southern and Northern Dynasties period that would follow afterwards.
This battle is famous not only because of its significance in history, but also because it demonstrated the importances of troop training, troop morale, troop loyalty and organized battle command. The battle was also significant in that it ensured that South China would remain independent until 589CE, when North China was again under a Chinese regime