<P> Yan remained in the background of Shanxi politics until the Nanjing government's failure to resist the Japanese takeover of Manchuria after the Mukden Incident gave Yan and his followers an opportunity to informally overthrow the Kuomintang in Shanxi . On December 18, 1931, a group of students (supported and perhaps orchestrated by officials loyal to Yan) gathered in Taiyuan to protest the Nanjing government's policy of not fighting the Japanese . This demonstration became so violent that Kuomintang police fired into the crowd . The public outrage that this "Massacre of December Eighteenth" generated was strong enough to give Yan's officials a pretext to expel the Kuomintang from the province on the grounds of public safety . After this event the Kuomintang ceased to exist in Shanxi except as a dummy organization whose members were more loyal to Yan than to Chiang Kai - shek . </P> <P> Future difficulties in securing the loyalty of other Chinese warlords across China, the ongoing civil war with the Communists and the ongoing threat of Japanese invasion motivated Chiang to let Yan retain the title of Pacification Commissioner in 1932, and he appointed Yan to the central government's Mongolian and Tibetan Affairs Commission . In 1934 Chiang finally flew to Taiyuan, where he praised Yan's administration in return for Yan's public support for Nanjing . By publicly praising Yan's government, Chiang in effect admitted that Yan remained the undisputed ruler of Shanxi . </P> <P> After 1931 Yan continued to give nominal support to the Nanjing government while maintaining de facto control over Shanxi, alternatively cooperating with and fighting against Communist agents active in his province . Although he was not an active participant, Yan supported the 1936 Xian Incident, in which Chiang Kai - shek was arrested by Nationalist officers led by Zhang Xueliang and released only when he agreed to make peace with the Communists and form a "united front" to resist the impending Japanese invasion of China . In his correspondence with Zhang Xueliang in 1936 Yan indicated that the growing rift between he and Chiang was due to Yan's anxieties over the potential for a Japanese invasion and a concern for the subsequent fate of China, and because Yan was not convinced of the correctness of focusing China's resources on anti-Communist campaigns . During the Xian Incident itself Yan actively involved himself in the negotiations, sending representatives to prevent Chiang's execution (and the civil war that Yan believed would follow) while pushing for a united front to resist the Japanese invasion of China that Yan believed was imminent . </P> <P> The financial relationship between Shanxi and the central government remained complicated . Yan was successful in creating a complex of heavy industries around Taiyuan, but neglected to publicize the extent of his success outside of Shanxi, probably to deceive Chiang Kai - shek . Despite his measured successes in modernizing the industry of Shanxi, Yan repeatedly petitioned the central government for financial assistance in order to extend the local railroad, and for other reasons, but his requests were usually denied . When Yan refused to send taxes collected from the trade of salt (produced in Shanxi's public factories) to the central government, Chiang retaliated by flooding the market of northern China with so much salt (produced around coastal China) that the price of salt in China's northern provinces dropped extremely low: due to these artificially low salt prices, neighboring provinces virtually stopped purchasing Shanxi salt altogether . In 1935 Chiang's announcement of a "five - year plan" to modernize Chinese industry was perhaps inspired by the successes of the "Ten - Year Plan" that Yan had announced several years before . </P>

Who encouraged foot binding in the yan dynasty