| Continued from above… had been so useful in Europe. The Hien entered combat in the spring of 1943 in the New Guinea war zone, covering New Guinea, the Admiralty Islands, New Britain, and New Ireland. The new Japanese fighter caused some pain and consternation among Allied pilots, particularly when they found out the hard way that they could no longer go into a dive and escape as they had from lighter Japanese fighters. 5th Air Force Commander General George Kenney found his P-40 Warhawks completely outclassed, and begged for more P-38 Lightnings to counter the threat of the new enemy fighter. The Kawasaki Ki-61 Hien ("Swallow") fighter represented a major departure for Japanese aircraft design in World War II. While other Japanese fighters were designed with air-cooled radials and were optimized for maneuverability, the Ki-61 used a liquid-cooled in-line engine and was designed for speed and power. In fact, the Ki-61 was so different from other Japanese fighters that when the type was first encountered in combat over New Guinea in June 1943, the Allies thought it wasn't a Japanese design at all. At first they believed it was a copy of the German Messerschmitt Me-109, then suspected it was a copy of the Italian Macchi C.202 Foglore or similar Italian fighter. For this reason they gave it the code-name "Antonio", or "Tony", though by the summer of 1943 the Allies were convinced the Ki-61 was in fact a Japanese design. | 
