In a remote area of Mongolia the 'Nomonhan Incident' lasted four months. This border skirmish between the Russians and Japanese ended in 1939, just 15 days after Germany invaded Poland and an isolated 35 by 20 mile section of land became a battlefield for more than 900 Soviet and 450 Japanese aircraft. Using the Ki-27 Nate fighter, Japanese pilots clashed with Soviet I-15 and I-153 biplanes and their I-16 monoplane. The soon to be antiquated massive TB-3 heavy bombers were also used and the Ki-21 Sally made its combat debut, eventually continuing service throughout the Pacific War. This was one of the first large aerial battles of modern times and the pilots used the conflict to practice and refine new fighting tactics which moved air power into the future of war. They sharpened up their missions and learned to place emphasis on reconnaissance, fighter sweeps, bomber escort, and infantry support. Both sides discovered and ignored tactical and design lessons from the combat to the detriment and advantage of each. Covering both the Japanese and Russian sides In The Skies of Nomonhanincludes loss lists, color profiles from both sides, plus more than 50 photos from Japanese and Russian archives all of which provide a new perspective on this interesting and largely unknown pre World War II encounter.