365 Murong Ke and the Former Yan capture Luoyang.
373 The Former Qin launch a campaign against Jin's western region, and conquers modern Sichuan, Chongqing and southern Shaanxi.
376 The Former Qin defeat and absorb the Former Liang state.
The Former Qin also conquer the Dai state, and push the Tuoba into the northern steppes. They then rule a unified north for the first time since the Western Jin.
378-9 The Former Qin attack and conquer the Jin border city of Xiangyang (Xianfan, Hubei). Weixing (Ankang, Shaanxi) also falls.
Another army captures Jin Pencheng (Xuzhou, Jiangsu), but then loses it again.
380 Former Qin's Fú Jiān spreads out his Di people throughout the empire, leaving Guangzhong with very few Di, but many Xianbei and Qiang, which would eventually have a destabilising effect.
383 The Former Qin suffer a catastrophic defeat at the Battle of Fei River or “Feishui”, against the Jin. The aftermath of the battle includes the Former Qin empire falling into massive civil war and its eventual destruction.
Fú Jiān also sends Lü Guang to Xiyu (Xinjiang and Soviet Central Asia) to mop up kingdoms that hadn't submitted to the Former Qin.
The Eastern Jin reclaim Henan south of the Yellow River after defeating the Former Qin.
Battle of Fei River, Wikipedia
Atlas of World History, ed. Jeremy Black, p 261
Das Tarimbecken, Wikipedia
The coloured background shows the status just prior to the battle of Fei River. After the Qin lose the battle, their border is pushed back to the dotted line.