One example might be Zhang Zoulin. In 1920s China, after the fall of the Qing, Zhang took advantage of the chaos of the early Republican period to seize control of its Manchurian provinces (Jilin, Heilongjiang and Liaoning), establishing a pseudo-state. His private army, the Fengtian Army, boasted huge numbers, up to 300,000 (though military upkeep crippled the economy.) Zhang's fief was buttressed by its geography, as routes to the northeast were limited—the large army could close passage at will—and by the Japanese, who were keen to buy influence. Zhang made forays into China proper, and this eventually bore fruit in 1926, when he temporarily controlled Beijing, with plans to capture the whole of China. The Nationalists, making progress towards unification too, fought Zhang in 1928. The Japanese Army, frustrated at Zhang's inability to stop the Nationalists, blew up his train later in the year, triggering a succession crisis which his son, Zhang Xueliang, eventually won.

Zhang's rule was interesting, but ultimately not sustainable. The massive military expenditure required to maintain independence and influence over affairs in North China was a source of significant discontent and stunted the Manchurian economy. The Fengtian yuan, the Ford's currency, dropped from parity to the Japanese yen to forty times higher, for instance, as Zhang struggled to make ends meet. The fundamental weakness of the economic base and the inability to foster a real society would ultimately lead to an uneasy alliance with the Nationalists in his son's reign. The Japanese annexed Manchuria in 1932, and the Nationalist refusal to escalate the incident forced Zhang to accept the loss of the fief and retreat into China proper to join the Nationalists—and become a bit of a troublemaker himself.

Rana Mitter, The Manchurian Myth: Nationalism, Resistance and Collaboration in Modern China, Berkeley: University of California Press (2000)