Khalkin-Gol War: Struggle for Mongolia, 1939

From BoardGameGeek:

Khalkin-Gol War: Struggle for Mongolia, 1939 is an operational-level, two-player wargame covering a “what if” Japanese-Soviet war in Mongolia in 1939. The historical campaign saw a series of limited actions in the late spring and early summer of 1939 along the Khalka River (Khalkin Gol) on the Manchukuoan/Outer Mongolian border. The campaign ended in a corps-level battle in August 1939 in which the Soviets decisively defeated the Japanese and produced a cease-fire between the two antagonists. The assumption of the game is that both Tokyo and Moscow decided instead to turn this into a full-scale war. Each turn of play represents a month of operations. Each hex on the map is approximately 30 kilometers across. Ground units are mostly built around divisions, with breakdowns into brigades and regiments. Air units represent anything from an elite squadron to a mediocre group. -description from the publisher