The Yokosuka(横須賀)D4YSuisei(彗星 "Comet") Navy Carrier dive bomber was operated by the Imperial Japanese Navy. Its Allied reporting name was "Judy". The D4Y was one of the fastest dive bombers of the war and only the delays in its development hindered its service while its predecessor, the slower fixed-gear Aichi D3A, remained in service much longer than intended. Despite limited use, the speed and the range of the D4Y were nevertheless valuable, and the type was used with success as reconnaissance aircraft as well as for kamikaze missions.
Lacking armor and self-sealing fuel tanks, the Suiseis did not fare well against Allied fighters. They did, however, cause considerable damage to ships, including the carrier USS Franklin which was nearly sunk by an assumed single D4Y and the light carrier USS Princeton which was sunk by a single D4Y.