The culture of the Japanese Army and its rigid command structure is critical in analyzing the strategies used by them in China from 1931-1939. The Kwantung Army was an anomaly in the greater study of the Imperial Japanese Army (IJA) from 1900-1945, in that it often took extra-judicial measures in its occupied territories and theatres of operations. Formed in 1919 from the original Kwantung Garrison, which since 1906 had guarded the southern Manchurian railway from bandits or enemy nations, the Kwantung garrisoned the Liaodong Peninsula. Occupation of this territory had begun during the First Sino-Japanese War of 1894-1895.
Kwantung Army in China, 1931-1937
In one incident a major group officers assassinated a pesky Manchurian warlord in 1928 by arranging for a bomb to be placed on his personal railcar. Evidence suggests that the Kwantung's unofficial policies may have indirectly led to their involvement in many major confrontations with Soviet border armies beginning in the mid 1920's. Their belligerence was most evident in Northern China.
Kwantung Cavalry, Manchuria 1937
The Kwantung's belligerence in 1937 and 1938 led in part to the Battle of Khalkhin Gol in 1939 and its escalation into a major theater of war from May to September. It should be noted that while the campaign in the Khalkhin Gol region was long and tens of thousands of troops were committed to Mongolia and Manchuria the bigger conflict taking place on the Chinese mainland was still the primary concern for Tokyo during this period. General Tojo had served in China and Inner Mongolia with the Kwantung and the IJA high command. Later he would hold command of the intelligence and military police operating in China until 1938 when he was recalled to Japan to begin his meteoric political career. 
Kwantung army infantrymen preparing for the harsh winter, 1937-38
Auxiliary and "collaborationist" cavalry in Mongolia, 1938-1945.
IJA machine gun crew in Manchuria, 1931
Opposed to being traitors many of the Hingan cavalry were in-fact considered patriots fighting for their (and their families') version of Mongolian nationalism alongside the puppet Manchukuo (Imperial) government forces and the Kwantung Army. It was the same in Manchuria where many fought out of loyalty to the former emperor Puyi and his royal family. 
These same Hingan troops were among the first to start mass desertions in 1945 and most refused to fight their brethren in the MPRA under any circumstances.  Their primary affiliation or faction was the Inner Mongolian, anti-Soviet and/or Bolshevik clique, though most were likely apolitical. Both Hingan and Mongolian participation in the conflicts seems to be downplayed or entirely omitted from histories dedicated to the period. See, the Battle of Khalkhin Gol: The Soviet-Japanese Border War of 1939, for more.
Imperial Japanese Army in Manchuria
 Uradyn, Bulag E. The Nomonhan Incident and the Politics of Friendship on the Russia-Mongolia-China Border
 Kolomiet, M. Order of Battle of The Khalkhin-Gol