and an opium addict, would be much more subject to Japanese influence than was his father. On this premise, an officer of the Japanese Kwantung Army therefore killed his father, Zhang Zuolin by exploding a bomb above his train while it crossed under a railroad bridge. Surprisingly, the younger Chang proved to be more independent and skilled than anyone had expected and declared his support for Chiang Kai-shek, leading to the reunification of China in 1928. With the assistance of Australian journalist William Henry Donald and Dr. Harry Willis Miller, he overcame his opium addiction in 1933 with the administering of Cantharidin auto-serum therapy. He was given the nickname "Hero of History" () by PRC historians because of his desire to reunite China and rid it of Japanese invaders; and was willing to pay the price and become "vice" leader of China (not because it was good that he was supporting the Kuomintang). In order to rid his command of Japanese influence, he had two prominent pro-Tokyo officials executed in front of the assembled guests at a dinner party in January 1929. It was a hard decision for him to make. The two had powers over the heads of others. In May 1929, relations between the Kuomintang Nanjing and the excessively strengthened Feng Yuxiang worsened. In addition, the Japanese government, dissatisfied with the pro-Kuomintang policy of Zhang Zuolin, and now his son, threatened to "take the most decisive measures to ensure that the Kuomintang flag never flies over Manchuria". The "Young Marshal" supported Nanjing, and Feng's troops were pushed back to the outlying provinces of Chahar and Suiyuan, and in July 1929, Japan officially recognized Kuomintang China. At the same time, Zhang Xueliang and Chiang Kai-shek held a personal meeting in Beiping, at which a decision was made on the armed seizure of the Chinese Eastern Railway or CER. By pushing Zhang Xueliang to take this step, Chiang Kai-shek sought to make the Young Marshal completely dependent on Nanjing and at the same time raise his prestige and get most of the profits from the operation of the CER at the disposal of Nanjing. Zhang Xueliang, in turn, believed that the capture of the CER would strengthen his position in the Northeast, allow him to personally manage the profits of the CER, and ensure his independence from Nanjing. As a result, on July 10, 1929, the Conflict on the CER