After his father was ruined by a late 19th-century depression, which ravaged the Chinese economy, Yan enrolled in a free military school that was run and financed by the Manchu government in Taiyuan.

[2] Yan eventually concluded that the Japanese had successfully modernized largely because of the government's abilities to mobilize its populace in support of its policies and to the close respectful relationship that existed between the military and civilian populations.

[3] Even before studying in Japan, Yan had become disgusted with the open and widespread corruption of officials in Shanxi and had become convinced that China's relative helplessness in the 19th century was the result of the Qing dynasty's generally hostile attitude towards modernization and industrial development and its grossly inept foreign policy.

The determination of Shanxi to resist Manchu rule was a factor leading Yuan to believe that only the abolition of the Qing dynasty could bring peace to China and end the civil war.

Yan's interest in having such a school active in Shanxi was sparked after staying in a western hospital in Japan for three months in which he was impressed by seeing modern medical equipment, including X-rays and microscopes, for the first time.

[13] To maintain Shanxi's neutrality and to free it from serious military confrontations with rival warlords, Yan developed a strategy of shifting alliances between various warring cliques and inevitably joining only winning sides.

The main causes of Yan's defeat were the low population and the lack of development in the areas that he had under his control, which made him incapable of fielding a large and well-equipped army similar to the ones commanded by Chiang at the time.

[23] After 1931, Yan continued to give nominal support to the Nanjing government while he maintained de facto control over Shanxi by alternatively co-operating with and fighting against Communist agents active in his province.

Although he was not an active participant, Yan supported the 1936 Xi'an Incident in which Chiang was arrested by Nationalist officers, led by Zhang Xueliang and Yang Hucheng and released only when he agreed to make peace with the Communists and form the united front to resist the impending Japanese invasion of China.

Despite his measured successes in modernizing the industry of Shanxi, Yan repeatedly petitioned the central government for financial assistance to extend the local railroad, and for other reasons, but his requests were usually denied.

Despite efforts to subject his officers to a rigorous Japanese-style training regimen and to indoctrinate them in Yan Xishan Thought, his armies never proved to be especially well-trained or disciplined in battle.

In general, Yan's military record is not considered positive (he had more defeats than victories) and it is unclear whether his officer corps either understood or sympathized with his objectives or entered his service solely in the interests of achieving prestige and a higher standard of living.

[19] While not particularly effective fighting rival warlords, Yan's army was successful in eradicating banditry in Shanxi, which allowed him to maintain a relatively-high level of public order and security.

Because most of the educated staff to whom he had access to were solidly entrenched within the landed gentry of Shanxi, it is possible that many of his officials may have deliberately sabotaged his efforts for reform by preferring that the peasants working their fields continue their traditional cheap labour.

Because Yan believed that human beings could achieve their potentials only through intense self-criticism and self-cultivation, he established in every town a Heart-Washing Society, whose members gathered each Sunday to meditate and listen to sermons based on the themes of the Confucian classics.

[40] In spite of his efforts, Yan did not succeed in making his school of thought widely popular in Shanxi, and most of his subjects refused to believe that his true objectives differed substantially from those of past regimes.

When the reinforcements sent by the central government forced the Communists to withdraw from Shanxi, the Red Army escaped by splitting into small groups, which were actively supplied and hidden by local supporters.

Three months later, the head of the Political Council, Prince De (Demchugdongrub), declared that he was the ruler of an independent Mongolia (Mengguguo), and organized an army with the aid of Japanese equipment and training.

[55] As the Japanese had advanced southward into Taiyuan Basin, Yan attempted to impose discipline on his army by executing General Li Fuying and other officers guilty of retreating from the enemy.

At Yuanping, a single brigade of Yan's troops held out against the Japanese advance for over a week, which allowed reinforcements sent by the Nationalist government to take up defensive positions at the Battle of Xinkou.

The defenders at Xinkou, realizing that they were in danger of being outflanked, withdrew southward, past Taiyuan, and left a small force of 6,000 men to hold off the entire Japanese army.

Wei prevented the Japanese from seizing the strategic Zhongtiao Mountain Range, but the loss of Linfen and Lingshi forced Yan to withdraw with what remained of his army across the Yellow River, into Yichuan County, Shaanxi, which closely neighbored the Communists' base, the Shaan-Gan-Ning Border Region.

An American reporter who visited Shanxi in 1944 observed that Yan "was thought of not necessarily as a puppet but rather as a compromise between the extremes of the treason at Nanjing and national resistance at Chongqing" by the Japanese.

[69] After the surrender of Japan and the end of World War II, Yan Xishan was notable for his ability to recruit thousands of Japanese soldiers stationed in northwest Shanxi in 1945, including their commanding officers, into his army.

[74] Most of the Communist casualties in the campaign occurred when they attempted to confront Peng's reinforcements in an orthodox battle, which allowed Yan's forces to target Liu's troops with their superior arms.

After losing southern Shanxi, Yan undertook preparations to defend Taiyuan to the death, perhaps in the hopes that if he and other anti-Communist leaders could hold out long enough, the United States would eventually join the war on their side and save his forces from destruction.

Shortly after arriving in Nanjing, Yan insinuated himself into a quarrel between the acting president of the Chinese Republic, Li Zongren, and Chiang Kai-shek, who had declared incapacity in January 1949.

Li went into exile in the United States, leaving Yan, who continued to serve as Premier in Taiwan, as the de facto leader of the Republic of China, until March 1950 when Chiang re-assumed the presidency.

[12] Throughout his rule, he attempted to promote social reforms that later came to be taken for granted but were highly controversial during his time, the abolition of foot binding, work for women outside the home, universal primary education, and the existence of peasant militias as a fundamental unit of the army.

During the 1930s, Yan became increasingly open to radical social and economic policies, including wealth redistribution via graduated taxation, state-led industrialization, opposition to the money economy, an orientation towards functional (vs. "moral") education and the large-scale assimilation of Western technology.