Generally refers to the south of the Yangtze River, but mainly refers to the middle and lower reaches of the Yangtze River in the Eastern Jin Dynasty, which is its ruling center, namely "Jiangzuo" and "Jiangbiao".

The pre-Qin dynasty was not a dynasty. Pre-Qin was one of the sixteen countries in Wuhu at that time (of course, the sixteen countries were not at the same time), and now it is still used to thinking that that historical period was the Eastern Jin Dynasty. At that time, it was called "five flowers".

3 crossing the river is a trap deliberately set by the Eastern Jin Dynasty:

There were spies in the Eastern Jin Dynasty in the army during the Battle of Feishui. At that time, there were too many pre-Qin troops and the communication level was not good at that time. The troops behind don't know the situation at the front. When the Jin army retreated to cross the river, the spies took the opportunity to spread rumors of defeat at the front line and demanded that the troops retreat, so the former Qin Dynasty was in flight.

After the Battle of Feishui, the former Qin Empire was divided, and nobles of all ethnic groups rose up in succession. He died in 394. North of the Northern Dynasties, Emperor Tuoba Tao of the Northern Wei Dynasty unified the North (439). The Northern Dynasty of the Southern and Northern Dynasties was not the former Qin Dynasty.