[Why] The Mongol Dzungar Khanate long held the northwest in fragmentation, contending with the Qing for influence in Xinjiang, Qinghai, and Tibet. Internal strife in the Dzungars gave the Qing court the historic strategic opportunity to solve the century-old frontier hidden danger in one blow. [What] Emperor Qianlong successively launched two western expeditions, first eliminating the Dawaqi Khan regime and then pacifying the Amursana rebellion. Qing general Zhaohui led the army on far expedition into southern Xinjiang, swept away the Greater and Lesser Khoja forces, and finally unified the entire region north and south of the Tianshan. [Who] Emperor Qianlong Hongli was the highest decision-maker of this great western expedition, personally writing the Ten Great Military Campaigns to manifest his achievement. General Zhaohui was the western-expedition mainstay, leading isolated forces in Heishuiying besieged for three months yet holding fast without retreat. [How] The pacification of the Dzungars formally incorporated Xinjiang into Chinese territory, laying the foundation of today's western frontier of China. It marked the final shaping of the Qing multi-ethnic empire's territorial pattern and is the key foundational event of modern Chinese territorial map.
Why
The historic event of Pacification of Dzungar represents a key developmental peak of the Huaxia dynastic system. The decisive western expedition that defined the western territorial map of modern China. By establishing this moral or administrative benchmark, it continues to shape the structural and philosophical fabric of ancient Chinese statecraft.