The Inner Mongolian Army was first formed by Prince Demchugdongrub with his personal bodyguard of 900 men in 1929. Although only armed with rifles and a couple of field guns from the Mukden arsenal, a gift of the Young Marshal (Zhang Xueliang) in 1929. His force became very efficient with the assistance of advisors from the Japanese Army. It was later expanded to 9 Divisions (8 of Cavalry) with 10,000 men for the Suiyuan Campaign of 1936 with the addition of Manchukuoan Mongol irregulars from Jehol under Li Shou-hsin, and various Mongol irregular troops from Chahar, and Suiyuan, bandits and Chinese deserters. Wang Ying lead a force of 6,000 Chinese troops in four brigades called the Grand Han Righteous Army.