The Yokosuka D4Y Suisei ('Comet') was a dive bomber of the Imperial Japanese Navy. Its Allied reporting name was 'Judy'. The D4Y was one of the fastest dive-bombers in the entire war, and only the delays in its development hindered its service, while its predecessor, the more robust but slower Aichi D3A remained in service for years. Despite this limited use, the speed and the range of the D4Y was nevertheless valuable, and the type was used with success as reconnaissance aircraft as well as in kamikaze missions.
Lacking armour and self-sealing fuel tanks, the Suiseis did not do well against Allied fighters. They did, however, cause considerable damage to ships, including the carrier USS Franklin, which was nearly sunk by a single D4Y.
The D4Y1-C reconnaissance aircraft entered service in mid-1942, when two of these aircraft were deployed aboard Sóryû at the Battle of Midway, where both were lost when Sóryû was sunk.
