 Zhang Xueliang and Guo Songling decided to secretly redeploy eight infantry regiments and two artillery brigades from Shanhaiguan sector to Jiumenkou.These secretly redeployed troops would be led by Guo Songling, but a personal conflict within the officers' corps almost cost the chance of a Fengtian victory.The incident began when artillery battalion commander Yan Zongzhou (阎宗周), a classmate of Guo Songling, was removed from command.