 Chinese Boeing P-26/281 fighters engaged Japanese Mitsubishi A5M fighters in the world's first dogfight between all-metal monoplane fighters.A unique mission in April 1938 saw two Chinese Martin B-10 bombers fly a mission over Japan, dropping only anti-war leaflets over the Japanese cities of Nagasaki and Saga.It was a war of attrition for the Chinese pilots, as many of their most experienced ace fighter pilots, such as Lieutenant Liu Tsui-Kang and Colonel Kao Chih-Hang, were lost.