Introduced into service early in 1938 during a time of extensive re-organisation of Army air units, the Ki-27, known as the 97 Sen by its pilots, achieved its first successes during the so-called 'China Incident' against the mainly biplane types operated by the Chinese. On 10 April 1938 Ki-27 pilots of the 2nd Daitai (later to become the 64th Sentai) claimed 24 Chinese biplane fighters shot down for the loss of only two of their own. Almost within a year of its combat debut against the Chinese the 97 Sen was to be tested in fighting against the Russians during the Nomonhan Incident of 1939....