The young Emperor Kangxi, after eliminating Oboi, also pacified the Revolt of the Three Feudatories.
The Three Feudatories refer to the Pingnan King Shang Kexi, the Pingxi King Wu Sangui, and the Jingnan King Geng Jingzhong, and the formation of the Three Feudatories traces back to the early Qing Dynasty. The Qing army took advantage of Li Zicheng's uprising to enter the pass and occupy Beijing, but due to insufficient Eight Banner troops, they had to rely on Ming Dynasty defectors to confront the Southern Ming court and peasant rebel forces. Wu Sangui and others rendered great service to the Qing Dynasty and were thus enfeoffed as kings. After the Qing eliminated the Southern Ming regime and suppressed various rebel armies, they stationed the Eight Banner troops in the north to guard the capital and other key cities, while sending Wu Sangui and others to garrison the south—Wu Sangui was sent to Yunnan, Geng Jingzhong to Fujian, and Shang Kexi to Guangdong—and these three were collectively called the "Three Feudatories."
Wu Sangui was the most powerful of the three feudatory princes, commanding tens of thousands of elite troops, along with twelve thousand Green Standard Army soldiers, and tens of thousands more, bringing his total forces to one hundred thousand, with all military commanders being his loyal confidants who answered only to him. This formidable military strength made the Qing court wary of him, so they granted him full authority over the provinces of Guizhou and Yunnan. Leveraging this advantage, Wu Sangui won over many civil and military officials sent by the court to Yunnan, turning them into his own followers. Economically, he also held great power, seizing the seven hundred qing estate of the Ming official Mu family, sending agents to Liaodong for trade, exchanging tea for Mongolian horses, and conducting commerce with Tibet. These measures allowed Wu Sangui to amass enormous wealth and steadily expand his influence.
Like Wu Sangui, Geng Jingzhong and Shang Kexi also possessed formidable military and economic power. These three feudal princes turned their territories into independent kingdoms, posing a serious threat to Qing rule. Additionally, the Qing government had to allocate twenty million taels of silver annually for military provisions to the "Three Feudatories," placing immense economic strain on the state.
Therefore, Kangxi had always attached great importance to the "Three Feudatories" issue, regarding it as a national priority on par with clearing the Grand Canal and managing the Yellow River, and he was constantly seeking an opportunity to eliminate the "Three Feudatories."
Wu Sangui and others knew that the Qing court did not trust them and would eventually eliminate them sooner or later. However, they were uncertain about Kangxi's attitude toward them. To test Kangxi, the Prince of Pingnan, Shang Kexi, took advantage of his request to retire and return to his hometown by asking Kangxi to allow his son to inherit his title.
This incident became a perfect opportunity for Kangxi to abolish the feudal domains. Kangxi agreed to allow Shang Kexi to retire to his hometown, but did not permit his son to inherit the title, and also proposed to disband the Pingnan Prince's mansion.
After Wu Sangui and Geng Jingzhong learned of this, they were both greatly surprised. To further test Emperor Kangxi, they requested that he abolish all three feudatories. Upon receiving their memorial, Kangxi disdainfully remarked, "How dare they threaten me." He then ordered his ministers to discuss countermeasures. Many officials opposed abolishing the feudatories, fearing it would force Wu Sangui to rebel with his army. However, several ministers, including Mingzhu, the Minister of War; Misihan, the Minister of Revenue; and Molo, the Minister of Justice, supported the abolition. Kangxi believed that the three feudal lords, commanding their own troops, would rebel regardless of whether the feudatories were abolished, so he decided to strike first and eliminate them. Thus, he granted Wu Sangui and Geng Jingzhong's request to abolish the feudatories.
Wu Sangui knew that rebellion was his only remaining option. Therefore, he killed Zhu Guozhi, the governor of Yunnan, declared his uprising, and wrote letters to Shang Kexi, the Prince of Pingnan, Geng Jingzhong, the Prince of Jingnan, and Zheng Jing in Taiwan, seeking to rally them to join his forces.
Wu Sangui issued a manifesto, accusing the Qing court of occupying Han Chinese land and forcing Han people to dress according to Manchu customs, claiming he would avenge the Ming Dynasty and drive out the Manchus. To win popular support, he ordered his troops to grow their hair long, wear Ming-style clothing, and carry white banners, styling himself as "Supreme Commander of All Forces for Punitive Expeditions." However, the people still remembered his crimes of inviting the Qing army through the Shanhai Pass and killing the Yongli Emperor, knowing that his rebellion was driven by personal gain, so they were unwilling to support him. Yet, many people were deeply dissatisfied with the Qing government's oppressive policies and seized this opportunity to launch anti-Qing uprisings. This allowed Wu Sangui's army to achieve continuous victories, advancing north to occupy all of Hunan Province, followed by Sichuan. Subsequently, uprisings erupted in Guangdong, Fujian, Guangxi, Shaanxi, Hubei, Henan, and other regions in response, plunging the Qing court into a crisis.
At this moment, Kangxi's extraordinary talent and bold vision were fully displayed. He concentrated his forces to attack Wu Sangui, executing Wu Sangui's son Wu Yingxiong in Beijing to demonstrate the Qing court's irreconcilable stance against Wu Sangui. He also adopted a strategy of division and disintegration, temporarily halting the revocation of fiefs for Geng Jingzhong and Shang Kexi, and announcing amnesty for other rebels, thereby isolating Wu Sangui. Subsequently, Kangxi ordered Lierjin and others to lead large forces to Wuchang and Jingmen to block Wu Sangui's northward advance from the front, and commanded Yuele to march from Jiangxi to Changsha, launching a pincer attack on Hunan together with Lierjin.
After the war began, the Eight Banner troops suffered consecutive defeats due to low morale, and those ordered to march to Wuchang and Jingmen lacked the courage to cross the river. In contrast, Wu Sangui's soldiers fought with exceptional bravery and valor. However, Wu Sangui made a conservative strategic error: after occupying the entire province of Hunan, he did not continue advancing north to attack Beijing but instead fortified his defenses in Hunan to resist the Qing army. Wu Sangui planned to attack Shaanxi from Sichuan on one front, joining forces with the rebel general Wang Fuchen, while on another front, he would strike Jiangxi from Changli to link up with Geng Jingzhong. This strategic deployment gave Kangxi enough time to respond effectively.
Kangxi decided to make Hunan the main battlefield, committing all efforts to annihilate the rebel forces there, while simultaneously opening fronts in eastern Zhejiang and Jiangxi, as well as in Shaanxi, Gansu, and Sichuan, to prevent the rebels from coordinating with each other; at the same time, he employed a strategy of stabilization to deal with Wang Fuchen, the provincial commander of Shaanxi, thwarting Wu Sangui's plan to break through to the northwest, and using a policy of amnesty and recruitment, Kangxi recovered Guangdong, leaving Wu Sangui isolated and without support. Trapped in Hunan, Wu Sangui put up a desperate resistance, but his situation grew increasingly passive.
In 1678, Wu Sangui was already sixty-seven years old. Seeing that the war situation was unfavorable, he hastily declared himself emperor in Hengzhou and bestowed titles and rewards upon his generals, hoping to boost morale and turn the tide of defeat. However, his fate of failure was already sealed; in August of that year, Wu Sangui fell ill from depression and ultimately died of illness. His generals then installed his grandson, Wu Shifan, as emperor to continue resisting the Qing forces.
In 1679, the Qing army recaptured Hunan and Guangxi, and the following year they retook Sichuan. Wu Shifan suffered consecutive defeats and was forced to retreat to Kunming to hold his ground. In 1681, the Qing army captured Kunming, Wu Shifan committed suicide, and the "Revolt of the Three Feudatories" was completely pacified.