News | May 10, 2022

LITERARY REVIEW: Yokosuka D4Y “Judy” Units

By Cmdr. Peter Mersky, USNR (Ret.)

When it attacked Pearl Harbor on Dec. 7, 1941, Japan’s navy was probably the most powerful and successful sea force in the world. Its ships, especially its aircraft carriers and their air wings carried what were at the time the best, and it wasn’t until perhaps the Battle of the Coral Sea in early May 1942, and then the Battle of Midway a month later, that they suffered their first major defeat. Yet, they were still a combined force to be reckoned with, even though new American designs such as the Grumman Hellcat and Vought Corsair, as well as the Essex-class of fleet carriers, were already beginning to enter service with both the U.S. Navy and Marine Corps, and Britain’s Royal Navy and Fleet Air Arm.

The iconic D3A dive bomber that was eventually codenamed “Val” by the Allies, was well-established in the Imperial Japanese Navy (IJN) and served in most if not all the theaters where Japanese carriers operated. But the Japanese were fast at work with the Val’s successor, which first flew in December 1940, surprisingly with a German Daimler-Benz in-line engine, one of a few Japanese designs to be so powered. Most Japanese army and navy combat aircraft used radial engines.

Named the Suisei (Comet), the D4Y1’s initial performance was as good as expected, but Japanese mechanics were not familiar with the German engine’s design, which initially gave problems and was eventually replaced by a Japanese Aichi, then Mitsubishi engine, with the Suisei going through D4Y2 to D4Y4. The new dive bomber saw its first action as early as Midway in June 1942, with fleet-wide use going through most of the mid- to late-war engagements in which the rapidly dwindling IJN participated. This somewhat mysterious but well-used dive bomber’s history and wartime career is well covered in this book, No. 140 in the Combat Aircraft series. It even saw service as a makeshift night fighter to combat the increasing number of large B-29 attacks that were soon devastating the Home Islands

The photos and Osprey’s dependable artist Jim Laurier’s profiles are fine. Mark Postlethwaite’s evidently final cover for Osprey (he is engaged in other pursuits) is one of the Combat Aircraft series’ most dramatic and atmospheric illustrations.

Although Osprey’s uniquely designed and well-illustrated soft-cover books are slowly increasing in price, they still offer great value for the money and coverage. No other publisher has developed such a line of distinct books that are rapidly covering every type of aircraft, conflict and history. This addition to the Combat Aircraft series is no exception.


Cmdr. Peter B. Mersky, USNR (Ret.) was commissioned through Aviation Officer Candidate School in 1968, and remained a reservist, serving in various intelligence billets as well as two tours with Light Photographic Reconnaissance Squadron (VFP) 306 until retiring in 1992. He was the first civilian editor of “Approach” magazine, has been a volunteer associate with "Naval Aviation News" since 1971, and has written NAN’s book review column since 1982 including more than 800 book reviews to NAN and other publications, including 16 books on U.S. Navy and Marine Corps Aviation.