The Mitsubishi Ki-21 (Allied reporting name: "Sally" /"Gwen") was a Japanese bomber during World War II. It began operations during the Second Sino-Japanese War participating in the Nomonhan Incident, and in the first stages of the Pacific War, including the Malayan, Burmese, Dutch East Indies and New Guinea Campaigns. It was also used to attack targets as far-flung as western China, India and northern Australia.
However, by the attack on Pearl Harbor and the start of the Pacific War, improvements in Republic of China Air Force fighter quality and quantities caused losses to mount, and most Ki-21-1a, -1b and -1c were relegated to training or second-line duties.
