If the Japanese had not lost at Khalkhin Gol, they may never have attacked Pearl Harbor. ...
In September, to discourage any Soviet move into Manchukuo and to prepare for renewed ground action if needed, the Japanese mounted an intense air campaign. For that purpose, six fighter squadrons were transferred from China. By September 13, the Japanese army air force had arrayed 255 warplanes, including 158 fighters along the front. Air battles swirled in Mongolian skies in the first and second weeks of September and climaxed on the 15th, as 200 Japanese warplanes struck Soviet air bases in Mongolia. Fierce aerial combat ensued as 120 Japanese fighters fought 207 Russian adversaries. All combat came to an end, however, when a cease-fire agreement was signed on September 16.
When Adolf Hitler invaded the Soviet Union in the summer of 1941, the Japanese were tempted to join the assault, but the shadow of Khalkhin Gol haunted them. With the influence of the Strike North group at an end, Japanese military planners began to look at British, French and Dutch colonial possessions in Southeast Asia as offering greater prospects for expansion.
Stalin remembered the fierce fighting in Mongolia as well. Even as he summoned 1,000 tanks and 1,200 warplanes from Soviet Far Eastern forces to battle the German invaders who were making spectacular gains, 19 reserve divisions, 1,200 tanks and some 1,000 aircraft remained in Mongolia to confront the Japanese. Although small by the standards of later World War II battles, the fighting between Soviet and Japanese forces at Khalkhin Gol cast a long shadow over subsequent events in the Pacific theater and on the Russian Front.
