Quanzhong's eldest son, Zhu Youyu () was also made an officer, though at this time he was yet a boy. The most important of these appointments was Zhu Zhen (), who was given special responsibility for selection, training and reorganization. Zhu Quanzhong did retain the hereditary officers in the guards and main army, but the reorganizations and preparations for war against Huang Chao had been entrusted to his own men. The Xuanwu army consisted largely of infantry. Having seen the effectiveness of the Shatou Turks' tribal cavalry during the recapture of Chang'an, Zhu ordered the formation of his own cavalry units. Command of the initial force was entrusted his military retainer Pang. Later as new units were formed, officers were both selected from men who had come with Zhu or recruited locally. Zhu soon had the opportunity to test the mettle of his new army. After his flight through Lantian Pass, Huang Chao attacked Cai Prefecture (蔡州, in modern Zhumadian, Henan), and the military governor of Fengguo Circuit (奉國, headquartered at Cai Prefecture), Qin Zongquan, defected to the rebels. Huang then proceeded to attack Chen Prefecture (陳州, in modern Zhumadian), but there the prefect, Zhao Chou, decided to resist even as his prefectural capital was put under siege. With Huang held up at Chen and his armies also meeting resistance in other prefectures, Zhu joined with the other governors of the region in early 884 to call in the man who had spearheaded the recapture of Chang'an – Li Keyong, military governor of Hedong (河東, headquartered in modern Taiyuan, Shanxi) and chief of the Shatuo Turks. In spring 884 the combined forces of Zhu and Li Keyong routed Huang's generals and forced him to abandon the siege of Chen. Suffering a string of defeats from the governmental armies, Huang again managed to flee eastward, but his career had now run its course. He was hunted down and killed later that summer. The final defeat of Huang Chao brought about the surrender of several rebel commanders to Zhu, strengthening his forces and providing him with a second group of officers who would serve him loyally in the years to come. Soon after Huang's defeat a quarrel occurred between Zhu and Li Keyong, and when Li Keyong passed through Bian, Zhu attempted to have Keyong assassinated during the night of June 11, 884. The attempt failed and Li Keyong escaped back to