In the 1939 Battle of Khalkhin Gol against the USSR in Mongolia, the Ki-27 faced both Polikarpov I-15 biplane and Polikarpov I-16 monoplane fighters.
Na razpis so se prijavila podjetja Nakajima, Mitsubishi in Kawasaki z letali Nakajima Ki-27, Mitsubishi Ki-33 ter Kawasaki Ki-28.