http://www.chinahistoryforum.com/index.php?showtopic=131
The Battle of the Fei River 淝水 was fought in the early winter of 383 AD.
Rolling Wave made a major error in saying that the former Qin 前秦 was defeated while crossing the Fei River. In fact, it was because the former Qin was standing off with the Eastern Jin's 东晋 Army of the Northern Garrison 北府兵 on opposite banks of the Fei River (a small river easily fordable on horseback) that Fu Jian 苻坚 decided not to risk a river crossing and to instead allow the Eastern Jin to cross over to his side. His idea was to attack the Eastern Jin while they were halfway across the river, as Sephodwyrm has pointed out. This is entirely in keeping with Sun Zi's Art of War: "When an advancing enemy crosses water do not meet him at the water's edge. It is advantageous to allow half his force to cross and then strike." However, Fu Jian made the mistake of not following another famous dictum from Sun Zi - to know one's enemy and know oneself.
Fu Jian did not understand his enemy well. Although he had defeated Eastern Jin armies on several previous occasions, he had never met the Army of the Northern Garrison in battle before this. The Army of the Northern Garrison was actually the only truly credible military force in the Eastern Jin. While it was nominally led by aristocrats of the Xie 谢 family, better known as fops and dandies than as military leaders, the bulk of that army was drawn from refugees from the same Huai River valley where the battle was now taking place (the Fei is a small tributary of the Huai). The Huai 淮 River area was a constant borderland and battleground between the Eastern Jin and the "barbarian" states to the north (contrary to popular belief, the border was not at the Yangzi River), and the people living there had become fierce and hardy warriors - this included the tough and wily General Liu Laozhi 刘牢之 who led the Northern Garrison vanguard. Furthermore, they knew the marshy ground there much better than the former Qin soldiers, who mostly hailed from the drier regions of the north.
In 379, the Army of the Northern Garrison with 50,000 troops had soundly defeated a 20,000-strong Qin attempt to build a bridge across the Huai River and invade the south. Fu Jian blamed this on the incompetence on the Qin generals involved, and punished them severely. But the quality of the Northern Garrison was again well demonstrated on the morning of the Fei River battle when its vanguard of 5,000 crossed the Luo Creek 洛涧 (another small tributary in front of the Fei River) and inflicted a major defeat on the Qin vanguard of 50,000 (Sephodwyrm says they numbered 15,000, but that was actually the number of casualties they suffered). This unexpected defeat at the hands of Eastern Jin troops apparently had a big impact on the morale of the Qin army, and even on the confidence of Fu Jian himself.
Nonetheless, the Qin army at the Fei River numbered 308,000 - this was the advance force commanded by Fu Rong 苻融; another 600,000 infantry and 270,000 cavalry had been left behind by Fu Jian on the northern side of the Huai River in his hurry to catch up with Fu Rong. Fu Rong had reported that the Eastern Jin force was small and the only fear was that they would escape, hence the eagerness to engage them in battle as soon as possible. Thus Fu Jian had hurriedly crossed the Huai with only 8,000 light cavalry to link up with Fu Rong's force at Shouyang 寿阳. Even this much reduced Qin army was more than three times larger than the Eastern Jin forces, which numbered 80,000. If they had met on equal terms, the Eastern Jin would still have been overwhelmed. The problem was that the Qin army collapsed even before the Eastern Jin finished crossing the Fei River to attack them.
The Battle of the Fei River 淝水 was fought in the early winter of 383 AD.
Rolling Wave made a major error in saying that the former Qin 前秦 was defeated while crossing the Fei River. In fact, it was because the former Qin was standing off with the Eastern Jin's 东晋 Army of the Northern Garrison 北府兵 on opposite banks of the Fei River (a small river easily fordable on horseback) that Fu Jian 苻坚 decided not to risk a river crossing and to instead allow the Eastern Jin to cross over to his side. His idea was to attack the Eastern Jin while they were halfway across the river, as Sephodwyrm has pointed out. This is entirely in keeping with Sun Zi's Art of War: "When an advancing enemy crosses water do not meet him at the water's edge. It is advantageous to allow half his force to cross and then strike." However, Fu Jian made the mistake of not following another famous dictum from Sun Zi - to know one's enemy and know oneself.
Fu Jian did not understand his enemy well. Although he had defeated Eastern Jin armies on several previous occasions, he had never met the Army of the Northern Garrison in battle before this. The Army of the Northern Garrison was actually the only truly credible military force in the Eastern Jin. While it was nominally led by aristocrats of the Xie 谢 family, better known as fops and dandies than as military leaders, the bulk of that army was drawn from refugees from the same Huai River valley where the battle was now taking place (the Fei is a small tributary of the Huai). The Huai 淮 River area was a constant borderland and battleground between the Eastern Jin and the "barbarian" states to the north (contrary to popular belief, the border was not at the Yangzi River), and the people living there had become fierce and hardy warriors - this included the tough and wily General Liu Laozhi 刘牢之 who led the Northern Garrison vanguard. Furthermore, they knew the marshy ground there much better than the former Qin soldiers, who mostly hailed from the drier regions of the north.
In 379, the Army of the Northern Garrison with 50,000 troops had soundly defeated a 20,000-strong Qin attempt to build a bridge across the Huai River and invade the south. Fu Jian blamed this on the incompetence on the Qin generals involved, and punished them severely. But the quality of the Northern Garrison was again well demonstrated on the morning of the Fei River battle when its vanguard of 5,000 crossed the Luo Creek 洛涧 (another small tributary in front of the Fei River) and inflicted a major defeat on the Qin vanguard of 50,000 (Sephodwyrm says they numbered 15,000, but that was actually the number of casualties they suffered). This unexpected defeat at the hands of Eastern Jin troops apparently had a big impact on the morale of the Qin army, and even on the confidence of Fu Jian himself.
Nonetheless, the Qin army at the Fei River numbered 308,000 - this was the advance force commanded by Fu Rong 苻融; another 600,000 infantry and 270,000 cavalry had been left behind by Fu Jian on the northern side of the Huai River in his hurry to catch up with Fu Rong. Fu Rong had reported that the Eastern Jin force was small and the only fear was that they would escape, hence the eagerness to engage them in battle as soon as possible. Thus Fu Jian had hurriedly crossed the Huai with only 8,000 light cavalry to link up with Fu Rong's force at Shouyang 寿阳. Even this much reduced Qin army was more than three times larger than the Eastern Jin forces, which numbered 80,000. If they had met on equal terms, the Eastern Jin would still have been overwhelmed. The problem was that the Qin army collapsed even before the Eastern Jin finished crossing the Fei River to attack them.
