The Nakajima Ki-84, also known as the "Frank," was a Japanese fighter aircraft used during World War II. It was designed to be a versatile and powerful plane, featuring a robust airframe and a strong engine that allowed for impressive speed and maneuverability. The Ki-84 was primarily used by the Imperial Japanese Army Air Service and became one of the most effective Japanese fighters of the war. First flown in 1943, the Ki-84 was equipped with heavy armament, including cannons and machine guns, making it formidable in combat. Its design incorporated lessons learned from earlier aircraft, resulting in improved performance and reliability. The Ki-84 played a significant role in defending Japan against Allied forces until the end of the war.