Although Chiang eventually agreed to end the civil war and work with the Communists against Japan, Zhang was placed under house arrest and the Northeastern Army was divided and reassigned to other commands.

[20] Nonetheless, they remained more loyal to their commander than to the state, and when the Russo-Japanese War temporarily destroyed any semblance of local Qing authority, they fought as mercenaries for both sides.

Yuan withdrew the New Army divisions from Manchuria, leaving Zhang Zuolin's border patrol battalion as one of the few military forces in the region.

[26] He was also named the Vice Minister of Military Affairs, but because his nominal superior had no local power base, Zhang was de facto head of all troops in Fengtian.

[c][35] In 1918, Zhang sent a contingent of the Fengtian Army to help the Beiyang Government put down Sun Yat-sen's Constitutional Protection Movement in southern China.

[37][38][39] It captured high-quality equipment, added a new division[d] and four new brigades, and left a 30,000-man garrison south of the Great Wall in a position where it could exert influence on the government in Beijing.

[44][45][47][48][49] The Fengtian Army had made heavy use of its artillery and some use of machine guns, but poor training and a lack of experience with modern weapons meant they had little practical effect.

Their superior rifles and grenades helped them secure control of the strategically important passes in Rehe by the time Feng Yuxiang's Third Zhili Army arrived.

[58] Further breakthroughs at Jiumenkou led by Jiang Dengxuan and his deputy commander Han Linchun (once again assisted by superior weaponry) forced Zhili to retreat from Shanhai Pass and only Wu Peifu's personal presence finally stabilized the battle lines.

[64] However, the provinces of central and southern China were outside of Zhang and Feng's direct military control and did not fully submit to their authority, although they were hesitant to openly defy it.

From December 1924 to late January 1925, Zhang Zongchang had to lead a detachment including the White Russians of the Fengtian foreign legion to put down the rebellious Qi Xieyuan in Jiangsu and Shanghai.

[73] During Guo's rebellion, the Guominjun had managed to drive Li Jinglin out of Zhili Province and Kan Zhaoxi out of Rehe in spite of the Second Army's dogged resistance.

In a major show of its logistical sophistication and proficiency with modern tactics, the Fengtian Army employed concentrated heavy artillery to overcome the next line of Guominjun defenses at Nankou.

[76] They targeted Wu first, and with the advice of Mikhail Borodin and Vasily Blyukher, Nationalist Commander-in-Chief Chiang Kai-shek won a series of rapid victories.

[77][78] Surprised by the KMT advance (Zhang was increasingly concerned with what he perceived as the rise of Communist influence in China), the Fengtian clique offered its support to Wu but was refused.

[80] In total the NPA counted 500,000 men, 100,000 of which was the Fengtian Army (excluding those portions based in Zhili and Shandong provinces, which by this point were functionally separate commands).

[91] In August, Sun Chuanfang launched an offensive into Jiangsu that seized Xuzhou and briefly put the NRA on the defensive, but by the end of the month he was in retreat and lost 50,000 men in September.

Despite Fengtian reinforcements in the form of air support and 60,000 soldiers, the united forces of Sun and Zhang Zongchang were unable to halt the Kuomintang advance.

Radical junior officers of the Kwantung Army, led by Kanji Ishiwara and Seishirō Itagaki, planned and executed the Mukden Incident on September 18, 1931, to give the Japanese an excuse to invade.

For one, almost half of the army (over 100,000 soldiers) was south of the Great Wall helping suppress a rebellion by Shi Yousan that had flared up in the aftermath of the Central Plains War.

[123] Within a few days, it had occupied cities along the length of the South Manchuria Railway and coerced or bribed the governors of Fengtian and Jilin Provinces to declare independence.

[124] The Northeastern Army mostly withdrew south of the Great Wall, but cavalry commander Ma Zhanshan led a doomed but highly publicized resistance campaign in Heilongjiang until early 1932.

Yang Hucheng and the Anti-Japanese Comrade Society wanted to stand and fight if the KMT army attacked, and refuse to negotiate until Zhang was released.

However, when a conference of Northeastern officers in January 1937 overwhelmingly resolved not to surrender peacefully, the CCP reluctantly decided that they could not abandon their allies and pledged to fight alongside them if the KMT attacked.

Mercenary service was attractive for White émigrés due to the fact that many of them had problems finding stable employment, and the warlords at least offered a regular income.

After the Fengtian Army's defeat in the First Zhili-Fengtian War, it was clear to Zhang and his advisors that the incompetence of these so-called "old men" had been a major contributing factor.

[187] A major difficulty for the Fengtian Army was that, at the start of the Warlord Era in 1916, none of the eight Chinese armories capable of producing new armaments were located in Manchuria.

He poured over 17 million yuan into expanding and improving the Mukden Arsenal, which was overseen by a series of talented superintendents: Tao Zhiping in 1922, Han Linchun in 1923, and Yang Yuting beginning in 1924.

[197] An English arms manufacturer, Francis Sutton, was paid to build a state-of-the-art trench mortar works nearby, and he helped Zhang set up a smuggling operation through Shandong.

[46][200] Starting in 1925, a chemical weapons plant was built in Mukden and Zhang Zuolin hired German and Russian experts to produce chlorine, phosgene and mustard gas.