Medieval China was a battle for kingdoms, with many infamous attacks waged for rule of many parts of the land. There would be however no battle as significant as the Battle for Fei River in Chinese history, a true underdog story.
By 383 AD, Fu Jian of the Former Qin had unified most of northern China under his banner after many years of battle. It was at this time when he attempted to implement his grand plan of unifying China by taking the Eastern Jin in the south. Over the previous decades Fu had conquered northern China winning numerous battles, however his army was predominantly made up of former tribesmen, disloyal to the cause with little or no training.
It was at this time that the Jin's attempted to recover the town of Xiangyang which had been taken by the Qin's earlier, however a branch of Qin's army numbering 50,000 were able to beat them back.
The Qin's response was to send over 900,000 troops to continue their push south, which culminated when the took the city of Shouchun. Fu left most of his army at Xiangyang, but sent a small force to take the Jin's believing in his greater numbers.
Knowing that his army severely outnumbered the Jin's, Fu Jian sent a messenger to persuade surrender, however the messenger was a Jin official who had been previously captured. The messenger tipped off the Jin's that the Qin army had not all arrived yet, and that they should seize the opportunity to take on the Qin's advance army.
Xie Xuan (The Jin Commander) led his Jin army of 5,000 against the Qin force, and were able to kill over 15,000 Qin soldiers. The Jin army spread themselves out to give the illusion that they had more soldiers than they did, which led Fu Jian to believe they had the numbers to match him.
After that battle the Qin continued to push ahead despite the discontent, confusion and awkwardness swelling in their ranks, and they shortly arrived at Fei river and set up camp on the western banks. The Jin forces arrived on the eastern banks but couldn’t proceed any further. Several General's of the Jin forces suggested to the Qin that they retreat a fraction so that Jin forces could cross the river and finish the battle. At this time the Qin's had over 800,000 troops in their ranks, while Jin's numbered no more than 80,000, but the Jin's were far more well trained.
Fu Jian thought this was a good idea and had plans to smash the Jin army while they were crossing. Fu's General's advised him not to do it due to the logistics in re-maneuvering such a large force, that were already demoralised, but Jian wouldn’t listen to them. Once Fu Jian told his army to retreat, they were confused, as many thought it was a full retreat and began running away from the battle in different directions.
The Jin saw this and used it to their advantage and moved their forces quickly across the river. Fu tried to consolidate his forces, but the Jin swiftly moved in and were able to decimate the far superior Qin, routing over 700,000 of the enemy's forces, while suffering only minimal casualties of their own.
After the heavy defeat Fu fled the battlefield, and his empire descended into a period of civil war.