張学良
On June 4, 1928, Zhang Zuolin was assassinated by the Kwantung Army, and his son Zhang Xueliang succeeded him. Hu Yukun was transferred to the post of Councilor of the Headquarters, Northeast Border Defence Army (). The next year, requisition of the Chinese Eastern Railway by Zhang Xueliang led to an armed conflict between Zhang and the Soviet Union. Hu was appointed Commander of the 2nd Army of the Defense Forces against Russia (). In 1930 Central Plains War broke out, Hu was appointed Commander of the 3rd Army of the Subjugation Forces (), and attacked the Anti-Chiang Kai-shek's Army.