The Kawasaki Ki-61 Hien (Kawasaki Army Type 3 Fighter), codenamed 'Tony' by the Allies, is a Japanese fighter used during World War II. The Allies initially mistook the Ki-61 for the Bf 109 and Macchi C.202, leading to initial code name 'Mike'. The Ki-61 was based off the Ki-60 and would be the only Japanese fighter to use an Inline engine. The Ki-61 first saw action during the Doolittle Raid in 1942.