The Warlord Era (simplified Chinese: 军阀时代; traditional Chinese: 軍閥時代; pinyin: Jūnfá shídài, 1916–1928) was a period in the history of the Republic of China when the control of the country was divided among former military cliques of the Beiyang Army and other regional factions, which was spread across in the mainland regions of Sichuan, Shanxi, Qinghai, Ningxia, Guangdong, Guangxi, Gansu, Yunnan, and Xinjiang. In historiography, the era began when Yuan Shikai died in 1916, and lasted until 1928 when the Nationalist Kuomintang (KMT) officially unified China through the Northern Expedition, marking the beginning of the Nanjing decade. Several of the warlords continued to maintain their influence through the 1930s and the 1940s, which was problematic for the Nationalist government during both the Second Sino-Japanese War and the Chinese Civil War.
This era was characterized by constant military conflicts between different factions, and the largest conflict was the Central Plains War which involved more than one million soldiers.
The historian Arthur Waldron shows that "warlord" is neither a Chinese word nor a Chinese concept. The Chinese term for "warlord" is junfa (軍閥), which was taken from the Japanese.
The origins of the armies and leaders which dominated politics after 1912 lay in the military reforms of the late Qing dynasty. These reforms did not establish a national army; instead, they mobilized regional armies and militias that had neither standardization nor consistency. During the later phase of the Taiping Rebellion (1850–64), provincial governors were allowed to raise their own armies to fight against the rebels; these forces were not disbanded even after the rebellion was over. The most powerful regional army was the northern-based Beiyang Army under Yuan Shikai, which received the best in training and modern weaponry. Officers were loyal to their superiors and formed cliques based upon their place of origins and background. Units were composed of men from the same province. This policy was meant to reduce dialectal miscommunication, but had the unfortunate side effect of encouraging regionalistic tendencies.