Short answers, pulled from the story.
The actions in Inner Mongolia from 1933 to 1936 involved military operations by Japan and proxy forces against Chinese resistance groups. These operations included the establishment of puppet states, the formation of the Anti-Japanese Allied Army, and subsequent invasions of Chahar and Suiyuan provinces.
Feng Yuxiang served as commander-in-chief while Fang Zhenwu held vice-commander duties for the Anti-Japanese Allied Army. Ji Hongchang led front-line operations with an estimated strength between 60,000 and 120,000 men according to various sources.
The Tanggu Truce was signed on the 31st of May 1933 and blocked further Japanese advance toward southern China. This agreement forced Imperial Japanese Army planners to turn their attention westward toward Inner Mongolia instead.
Prince Demchugdongrub enlarged his army from three cavalry divisions to nine divisions using Japanese advisors following the initial defeats. By July 1937 these forces reached 20,000 men organized into eight cavalry divisions.
Chiang Kai-shek believed communists dominated the Anti-Japanese Allied Army and viewed it as a threat to his authority. The Kuomintang military committee issued orders cutting passenger train service to Kalgan in early July to enforce this blockade.