By Pierre Kosmidis
Text, photos and additional information by Dan Farnham, used by permission
The WW2 Pacific Treasures of Kwajalein Lagoon by Dan Farnham PART 2 – Warrant Officer Nobuo Fujita, the only man who has bombed the continental US and the story of the E14Y1 floatplanes found in a shipwreck
The WW2 Pacific Treasures of Kwajalein Lagoon by Dan Farnham PART 3 – “Gegibu Betty”, the Japanese G4M bomber found in an uninhabited island of the Pacific
The WW2 Pacific Treasures of Kwajalein Lagoon by Dan Farnham PART 4 – The Aichi E13A “Jake” wrecks of Ebeye island
The WW2 Pacific Treasures of Kwajalein Lagoon by Dan Farnham PART 5- The F1M2 ‘Pete’ wreck at the Shoei Maru
The WW2 Pacific Treasures of Kwajalein Lagoon by Dan Farnham PART 6 – The H6K ‘Mavis’ float plane wrecks of Ebeye Island
On May 19, 1937 the Japanese Navy submitted preliminary specifications for a Navy Experimental 12-Shi Carrier Fighter. The new design was to replace the A5M ‘Claude’ carrier fighter which was already operational in the fleet.
The plane that was produced by Mitsubishi in response to the request would be the A6M carrier fighter, which to this day remains the most-recognizable symbol of Japanese air power of World War II.
The A6M is universally known as the Zero, from its Japanese Navy type-designation ‘Type 0 Carrier Fighter’, taken from the last digit of the Imperial year 2600 (1940) when it entered service. In the short-designation system used by the Japanese Navy, it was given the designation A6M.
The ‘A’ was the letter given to carrier fighters, the ‘6’ indicated it was the sixth type of carrier fighter accepted into service by the Japanese Navy, and the ‘M’ stood for Mitsubishi.
Numbers following the ‘M’ indicated the major production versions, such as A6M2, A6M3, and so forth. The last major production version was the A6M5. The Zero remained in production until 1945, with over 11,000 built.
Under the Allied codenaming system which was put into use starting in 1942, fighter planes were given male names, and the name chosen for the Zero was “Zeke”.
Two A6M1’s were produced for flight testing. Testing went well, and the only notable changes to the design was the replacement of the two-bladed prop with a three-bladed prop, and installation of a more powerful engine. The improved design was ordered into production by the Japanese Navy as the A6M2.
Armament consisted of two 7.7mm machine guns in the nose, and two 20mm cannon in the wings. The A6M2 could also carry up to 264 pounds of bombs. Top speed was 335mph, and it had a range of just over 1,100 miles. Later versions of the Zero, such as the A6M5, had upgrades such as a more powerful engine and various changes to its armament.
One version of the Zero, a float-equipped variant built by Nakajima and designated the A6M2-N, was given the codename ‘Rufe’. Another variant, the A6M3 Type 32, had squared-off wingtips and was given the codename ‘Hamp’. Both planes, when they first made their appearance, were not immediately recognized by the Allies as being variants of the Zero. But even after the Allies realized this, the codenames stuck.
The Zero quickly gained a fearsome reputation. It came as a nasty surprise to the Americans, who at the time had assumed that the Japanese could not compete in modern fighter design.
The attack on Pearl Harbor, and the subsequent battles at the Coral Sea and Midway showed that in experienced hands, the Zero was a deadly opponent.
It took a heavy toll on Allied aircraft wherever they had the misfortune to meet the Zero in combat. At the beginning of the war, Allied aircraft were simply outclassed by the Zero, and they fell to the Zero’s guns on a regular basis.
But the Zero failed to achieve complete air superiority due to the development of suitable tactics by the Allies which offset the Zero’s advantages.
By 1943, inherent design weaknesses and the increasing lack of more powerful aircraft engines meant that the Zero became less effective against newer Allied fighters which possessed greater firepower, armor, speed, and approached the Zero’s maneuverability.
In addition, like most other Japanese aircraft of World War II, the Zero lacked armor protection for the pilot, nor did it carry self-sealing fuel tanks.
While these weight-saving measures gave the Zero phenomenal performance and range, it also meant the Zero was prone to catching fire and exploding when struck by enemy gunfire- a trait also shared with many other Japanese aircraft of World War II.
When the powerful American F6F ‘Hellcat’ and F4U ‘Corsair’ fighters appeared in the Pacific theater, the Zero lost its competitiveness.
In addition, the ever-decreasing number of experienced Japanese pilots became a significant factor in Allied successes. Nonetheless, right until the end of the war, in competent hands the Zero could still be deadly.
In the years leading up to the Pacific War, the Japanese fortified several atolls in the Marshall Islands, including Kwajalein Atoll where an airfield was established on Roi Island.
Several different Zero squadrons were based at Roi, up until Kwajalein Atoll was seized by American troops in early 1944 during Operation Flintlock.
The first of these units was the Chitose Air Group, which was based at Roi from late August 1941 until December 1942. The Chitose Air Group was initially equipped with the A5M ‘Claude’, which was the direct predecessor to the Zero, but the unit later transitioned to Zeros.
It is unclear exactly when the transition happened, although it would have been sometime after February 1, 1942.
That was the date of the first American carrier strike on the Marshall Islands, and US Navy pilots reported encountering Zeros in combat during the strike. This reporting was in error- at that time, the Chitose Air Group only had the earlier A5M ‘Claude’ fighters.
Production of the Zero had not yet caught up with demand, and at the time of the hit-and-run raid on February 1, all the Zeros were still going to the fleet’s aircraft carriers and other first-line units. So, the transition to Zeros at Roi would have been sometime between February and December of 1942.
The Chitose Air Group was reorganized as the 201st Kokutai (Naval Air Group) on December 1, 1942, by which time it was operating the A6M2 variant of the Zero. In February 1943, the 201st left Roi and returned to Japan.
The 252nd Kokutai took over on Roi when the 201st returned to Japan. The 252nd established its headquarters on Roi, and the unit had detachments at Wotje, Taroa, and Eniwetok atolls.
The 252nd operated the A6M2 variant of the Zero, and transitioned to the A6M5 in mid to late 1943. In December 1943, the 252nd was joined by the 281st Kokutai, which was equipped with the A6M2 variant, and both units operated from Roi until their destruction during Operation Flintlock.
Other Zero units that operated briefly from Roi were the ‘Junyo’ carrier air group, which had a detachment at Roi in the summer of 1943. Also, the ‘Shokaku’ carrier air group had a detachment at Roi for two weeks in late 1943. But neither of these units were permanently assigned to Roi.
Not long after World War II ended, the neighboring islands of Roi and Namur were made into one island when landfill was brought in. The two islands are now one, referred to as ‘Roi-Namur’. But the most common name used among Kwajalein Atoll residents is simply “Roi”.
One Zero has been found in the Kwajalein lagoon since the end of World War II, and it lies just half a mile off Roi’s main pier, at a depth of 55 feet. It is a land-based version of the A6M2, easily distinguishable because the carrier-related equipment such as the tail hook is not present on the plane.
Land-based Zeros had such equipment removed to save weight, and the opening for the tail hook was faired over to reduce aerodynamic drag.
The Zero lies upside down, and is broken just behind the cockpit with the tail folded over almost on top of the plane. One of the landing gear struts lies not far from the plane, and pieces of the engine cowling are scattered nearby.
The guns are still in the wings, and one access panel on the right wing is open which provides a view of an ammunition drum.
Over the years that I’ve lived at Kwajalein Atoll, I’ve heard speculation that the plane was shot down in combat. Another theory has it that the plane was dumped by the Japanese.
Yet a third theory has it that the plane crashed accidentally while trying to land or take off, since the wreck lies directly in line with the runway as it existed at the time when the Japanese had their airfield on Roi.
Of those theories, the physical state of the wreck seems to best support the ‘accidental crash’ theory. If the plane had been merely dumped by the Japanese, usable items such as the guns, engine, and other parts would have been cannibalized from the plane before it was discarded.
The scattering of debris, such as the landing gear and pieces of the engine cowling, indicate an impact with the water that was hard enough to break pieces of the plane off, but not hard enough to totally destroy the plane as a high-speed impact would have been.
The propeller blades are not bent, indicating that the engine was most likely shut off, or at idle, at the time of impact. This would also support the ‘accidental crash’ theory.
Unfortunately, we may never know the exact date this Zero crashed, or even which unit was operating it at the time it went down, because the Japanese units on Roi destroyed most of their records and documents when they realized the island was about to be invaded by the Americans.
Regardless of why it crashed, having an example of Japan’s most feared naval fighter of World War II is another reason that diving at Kwajalein Atoll is so great for history buffs.
It provides an opportunity for divers to get an up-close look at a plane that struck terror into Allied aircrews in the first years of the war, but was ultimately bested and unable to save Japan from being defeated in World War II.