"Return to the Start Line" -- After the incident of Chang Kufeng, Japanese considered that the Halha River
defined the border between the Mandchuoko and Mongolia. In April 1939, the Kwantung Army was ordered to deal with border incidents and punish the “illegal violations” perpetrated by the Soviet-backed Mongol troops. On May 14, a recon detachment, composed of a squadron of cavalry and a company of light tanks under the command of Lt Col. Azuma Yaozo, arrived in the area of Nomonhan. On the 15th, Azuma, reinforced by a detachment of Manchurian cavalry, launched a pincer movement aiming to trap the Mongol troops outside Mongolia.
Attacker: Japanese (64th Regiment, 23rd Infantry Division, Army of the Kwangtung and Manchurian auxiliaries)
Defender: Mongolian (Infiltrating Mongols and Mongol Obsevation Station)