The National Pacification Army (NPA), also known as the Anguojun or Ankuochun (), was a warlord coalition led by Fengtian clique General Zhang Zuolin, and was the military arm of the Beiyang government of the Republic of China during its existence.
The army was formed in November 1926 after the Fengtian victory in the Anti-Fengtian War, the NPA was tasked with countering the advance of the Kuomintang (KMT)-aligned National Revolutionary Army (NRA) of Chiang Kai-shek, who had launched the Northern Expedition in June 1926. In addition to its Fengtian Army core, the NPA also included Zhili clique generals, such as Sun Chuanfang. The NPA suffered a series of serious military defeats inflicted by Chiang and his warlord allies, including Feng Yuxiang, Li Zongren and Yan Xishan. On the southern front, the NPA was pushed back from Jiangsu and Henan after fierce fighting against the Guominjun and the NRA. On the western front, they fought Shanxi forces under Yan Xishan. Following these setbacks, a conference of NPA leaders in June 1927 established a military government and proclaimed Zhang Zuolin as Generalissimo, whereupon all military and civilian power was placed in his hands.
Despite having achieved a few victories in mid-1927 in Jiangsu and extensive victories in Shanxi, the NPA could not defeat the Kuomintang forces and soon retreated north and east of Tianjin. Following Zhang Zuolin's assassination by the Japanese Kwantung Army in the Huanggutun Incident on 4 June 1928, he was succeeded by his son, Zhang Xueliang, who disbanded the National Pacification Army and swore allegiance to the Kuomintang government in Nanjing.
Background
China fragmented into various warlord factions as part of the tumultuous Warlord Era during the 1910s which started from the Xinhai Revolution. Many provinces became autonomous under their ruling generals. Following the National Protection War against Beiyang Army general-turned-emperor Yuan Shikai, China became balkanized into a collection of regional power networks, the feud between different factions intensified, and warlordism was born.
The Fengtian clique had been formed under Zhang Zuolin, who was the local hegemon in Manchuria. Zhang's Fengtian Army was the backbone of his influence and allowed him to make mutually-beneficial alliances with local elites. In response to the growing dominance of China by the Anhui clique, an opposing warlord group consisting of the Fengtian and Wu Peifu-led Zhili cliques banded together. This coalition expelled the Anhui clique from Beijing in the Zhili–Anhui War, pushing them southwards and allowing the Fengtian and Zhili cliques to jointly control the capital. However, this order fell, with the Zhili and Fengtian cliques going to war in the First Zhili–Fengtian War. Zhili won, pushing Fengtian back to Manchuria.
In 1924, Zhili-aligned Jiangsu governor Qi Xieyuan declared war on Fengtian-allied Zhejiang governor Lu Yongxiang, sparking a new conflict between the Fengtian and Zhili cliques, called the Second Zhili–Fengtian War. The decisive moment of the conflict came on 30 October 1924, when warlord Feng Yuxiang broke from the Zhili clique, declared the establishment of the independent Guominjun, and aligned with the Fengtian in his Beijing Coup. This led to an overwhelming Fengtian victory, the removal of the Zhili clique from the capital and Cao Kun from the presidency of the Republic of China, and placed Zhang Zuolin in control of the Beiyang government.
Fengtian thus took control of Zhili and Shandong provinces, with the Zhili clique routed southwards, where warlord Sun Chuanfang established control of the provinces of Zhejiang, Jiangsu, Anhui, Fujian, and Jiangxi. The army he created he named the Allied Army of the Five Provinces (). The fragile peace following the Second Zhili–Fengtian War did not last long, as Feng Yuxiang and Zhang Zuolin quickly turned against each other. Both had been seeking an alliance with the Zhili clique, but Wu Peifu, in an attempt at revenge, sided with Zhang in the Anti-Fengtian War. In October 1925, Sun Chuanfang began the invasion of Jiangsu, and Feng began his invasion of Shandong, which was now under the control of Fengtian general Zhang Zongchang. In November 1925, general Guo Songling turned against Zhang Zuolin, siding with Feng. In January 1926, Zhang launched an offensive, ordering his troops in Fengtian and Shandong provinces to invade Beijing and Tianjin.