Empire of Japan (1941)

Multirole Medium Bomber: 1170 built

Designed as a replacement for the aging G3M ‘Nell’, as a long range bomber and torpedo attack aircraft, the G4M represented a comprehensive improvement. In this plane, the Imperial Japanese Navy found a high speed bomber capable of carrying out raids, and engaging enemy ships at sea at otherwise unheard of ranges. During the campaigns in China, and first year of war in the Pacific, the G4M wrought havoc on Allied forces on land and at sea. However, its range and speed were achieved in sacrificing crew and fuel protection, and as the tide of war turned, the same design philosophy that gave the G4M its lethal edge, would see the crews flying the aircraft endure staggering losses.

The Road to War

The Imperial Japanese Navy rose to rapid prominence in the late 19th to early 20th centuries, alongside the equally rapid pace of Japan’s industrialization. Its victory against the Qing during the first Sino Japanese war saw them claim Korea and lay the ground for future Imperialistic inroads into continental Asia. Against Russia in the Russo Japanese war, they shocked the world after demolishing two major fleets and seizing Port Arthur, this being the first time a European country had lost to a non-european industrial power. The rise of Japan’s naval strength was a necessity of its mission, accepted since it first began industrialization, to expand its economic sphere and gain access to the necessary resources which home islands lacked. Oil, rubber, and ore were the foremost of its material needs, but there was also a desire to prove the racial superiority of the Japanese over the people of Asia, and rise above the Europeans and Americans who dominated the region. In the long term, this set the stage for brutal wars of expansion, conducted using the most advanced weapons available, over distances that dwarfed nearly every military campaign that had since been conducted. However, to fight such wars, the newest weapons of war and methods of manufacture had to be sought out.

The United Kingdom would prove an ideal partner in this, and would prove to be a critical source for military aid and equipment, and an alliance began in 1902, lasting two decades. Britain’s aim in this agreement was to ensure that the Russian Empire would not become a challenge to them in Asia. Among the earliest and most visible boons of the alliance was the Battleship Mikasa, purchased from Britain, and serving as the Japanese flagship during the Russo Japanese war. Over the coming decades, the exchange would bring invaluable experience, and modern equipment to Japan. By the end of the First World War, Japan had grown considerably as a naval and industrial power, with an economy now dependent on agricultural imports from continental Asia, and oil from Borneo and America. Their European colonial challengers were also diminished in number, with Russia’s navy diminished even further during the revolution, and Germany losing its Pacific and Asiatic holdings, to Japan’s gain.

Naval planners thus looked to new opportunities and conquests. The greatest of these was China, by then descended into warlordism, but an economic power nonetheless. By the start of the twenties, the Washington Naval treaty would affirm the integrity of Chinese territory in spite of the conflict there, and assure equal economic rights for those wishing to trade. While the Japanese government would maintain these two principles for the rest of the 1920’s, the Navy itself was becoming more dominated by voices seeking to challenge the treaty and other agreements as being strictly tools of European and American naval dominance and interests. A faction led by Vice Admiral Kato Kanji would hold to a different principle, asserting that “the United States, by its limitless economic resources, by its pursuit of policies of economic aggression, and, in China in particular, by its provocation of anti-Japanese activities, threatens the Japanese position in China for which our nation has risked its destiny.”

While Japan had yet to experience the era of political turmoil, assassinations, and the subsequent rule by the military, the roots of the eventual conflict with the US were found in the years after the Great War. In accordance with the anti-treaty faction, the United States was selected as the chief ‘hypothetical enemy’ when the nation’s Imperial Defense Policy was revised in 1923. Doing so not only meant challenging a materially and technologically superior opponent, but also claiming much of Asia for itself as a matter of industrial, and racial, destiny.

Building an Arsenal

To face the United State and European powers, modernization was paramount. In aviation, the greatest step came with the post-WWI Sempill Mission. While Japan had a nascent aviation industry which had begun development during the Great War, nearly every plane in use was imported, and what was domestically produced was of foreign design. As part of the last major exchanges in the dying Anglo-Japanese alliance, the Japanese Navy requested assistance in the field of aviation from the British in 1920. While there were major disagreements within Britain on such a technology transfer, the hopes for major partnerships and sales with the British aviation industry overcame such doubts. The mission arrived the following year, led by former RAF officer Baron Sir Williams Frances-Forbes, who had brought with him experts in aircraft design, construction, training, and use. Materially, he brought airplanes of nearly every type from fighters to torpedo planes, numbering over a hundred in total. The mission at Kasumigaura would prove to be nothing less than a spectacular leap for Japanese military aviation, putting it well on the path to self sufficiency. Combined with the Royal Navy’s advice on the construction of the Japanese aircraft carrier Hosho, the first carrier built from the ground up for the role, Japan would now possess some of the most essential tools in the wars to come. Just as the technical assistance ended, so too did the alliance with Britain, which lapsed in 1923.

The airplane industry grew slowly, first as a series of small shops producing a modest number of mostly foreign planes, but growing into larger enterprises. The largest of these manufacturers were Mitsubishi, Nakajima, and Kawasaki, which provided the nucleus for the rest of the cottage industry based aviation sector. Arguably the largest of these was Mitsubishi Heavy Industries, through its branch, the Mitsubishi Internal Combustion Engine Co. at Kobe. Concurrent with the Sempill mission, the company’s aircraft manufacturing effort was shifted to Nagoya, which would remain the center for Mitsubishi’s airplane development and production. In the years to come, additional production plants would sprout from the main facilities in Nagoya, with separate airframe and engine departments being founded by 1935.

While the aviation industry was slowly rising, the primary means of war against the United States navy was to draw in, and then attack the enemy fleet once it was deep within Japanese territory. It was hoped that through this single decisive engagement that any war could be quickly be settled, and thus Japanese supremacy over Asia was assured. It wasn’t until far later that the US would heavily outnumber the Japanese fleet, and serious changes would need to be made to this strategy. The general approach to this disparity was two contradictory schools of thought. The first was to overmatch the enemy on the technical and operational level, most clearly demonstrated in the development of highly effective oxygen fueled torpedoes, outranging the enemy with superior long range gunnery, and the development of keen night-fighting training. Against this program was the belief that any material disparities could be overcome by the superior, unique qualities of the martial spirit of the Japanese soldier, whose supposed unwavering morale and willpower could deliver victory against a better equipped enemy.

This strategy was entirely battleship focused until the thirties, with aviation playing a very small role until several crucial technical developments were rolled out. Aircraft at the time had a very limited range of action, small payloads, and were very fragile. Even though the Japanese Navy had been among the first to use aircraft in combat in the First World War, the airplane was seen as a tool for local defense and reconnaissance. Torpedo aircraft were particularly promising, but in a naval doctrine that required striking out with overwhelming force at long ranges, wood and canvas biplanes simply were not up to the task.

It was the development of all-metal, streamlined, monoplanes that proved to be the deciding factor in shifting the idea of the airplane as a defensive weapon, to one which could deliver deadly blows from afar. As the striking range of aircraft increased, so too did the potential range of the ‘decisive battle’, which by the late 1930s was planned for around the Marianas. As these technical developments progressed, Japan would find itself evermore under the influence of the military, whose factions would launch a war against China. They would seize Manchuria in 1932, and planned larger campaigns deep into the Chinese heartland. Given the vast distances involved, the Imperial Japanese Army and Navy sought new bombers with unprecedented range to reach targets over a thousand nautical miles away.

Rikko

The war against China, and the predicted war with America, would require the use of aircraft in roles that were restricted by available plane’s very modest performance. Crucially for the Army and Navy, by the mid 30’s, light and medium bombers were growing ever more capable, and Japan’s aircraft carrier program was world class. At this time, Rear Admiral Yamamoto Isoroku, the chief of the technical bureau of the Naval Aviation Department, was pursuing a program to achieve technical independence from foreign manufacturers. However, he had not merely wished for autonomy in aviation, but was interested in developing several new, critical weapons.

Among the first of these was a long range, land-based attack aircraft or, Rikujo Kogeki-ki. At the direction of Vice Admiral Matusyama Shigeru, Rear Adm. Yamamoto and his team were directed to research the requirements for a long range bomber capable of engaging targets with bombs or torpedoes in support of the battlefleet. With their findings, they approached Mitsubishi with the requirements for a new aircraft. This materialized in the Mitsubishi G1M, a modern twin engine bomber and reconnaissance aircraft. The experimental plane first flew in 1934 and was to provide the basis for a new bomber design.

The new Mitsubishi G3M was developed by head designer Honjo Kiro. Much like the G1M, it was a sleek, all metal, twin engine aircraft. It had a range of 1540 nautical miles and an 800kg payload, presenting a very impressive level of performance for 1935. Particularly impressive was its range, which was beyond any other bomber save for the nascent Boeing B-17 under development in the United States. Achieving this range was largely a factor of streamlining, and some very extreme weight saving techniques. This included foregoing any protection for the fuel tanks and crew. Fragility aside, the aircraft was almost exactly what the Navy was looking for, with Captain Onishi Takijiro, head of the Instruction division at Koku Hombu, expressing great satisfaction with the new plane when he inspected the Kisarazu Air Group in 1936, this being among the first of the new Naval land attack units.

The G3M would serve the Navy well in China, where it attacked distant targets, being defensive positions, and cities, in an attempt to prevent their fortification and cow the Chinese government into capitulating. The bomber was as the Navy wished, but they found that it was extremely vulnerable to enemy fighters, given its lack of armor and modest defensive armament. Despite the experiences in China, and the heavy losses incurred, the Navy was largely disinterested in the succeeding design possessing any greater protection than the G3M. Instead, they requested a twin engined design with a maximum speed of 215 knots at an altitude of 3 km, a range of 2600 nautical miles, and a combat range of 2000 nautical miles. They did not request any increase in payload size, but the overall design requirements were extreme. Given the G3M was already a streamlined design, which required major compromises to its protection in order to achieve its speed and range, producing an aircraft some 27 knots faster and capable of flying 460 nm further would prove extremely challenging.

There would be no competition for the design, as Mitsubishi received the development contract directly from the Navy in September of 1937. Honjo Kiro would again be called upon to lead the design effort, though he would be in the United States until October of that year. Finding the Navy’s requirements for the new plane bordering on unreasonable, Kiro would instead suggest a four engined design, feeling the requested pair of 1000 hp Mitsubishi Kinsei engines being inadequate. During early design proposals with Naval staff officers, he would attempt to introduce a four engined rikko, but was angrily rebuffed by Rear Admiral Misao Wada, the chairman of the congress. The admiral, nearly losing his temper, shouted “The navy will decide matters of operational need! Mitsubishi should just keep quiet and build a twin engined attack aeroplane in accordance with navy specifications! Erase the drawing of the four engined aeroplane on the blackboard at once!”

Honjo was thus forced to return to the twin engined concept, and was also given a new requirement that the aircraft feature a defensive 20mm cannon at its tail. The list of requirements now completely eliminated the possibility that the new design could be a derivative of the previous G3M. Heading the team on his return to Japan in April of 1938, Honjo oversaw the program, joined by Kushibe Shiro and Hikada Tetsuro. He had the benefit of wind tunnel research conducted the previous December, but would have the unenviable task of designing to the Navy’s unchanged requirements. The G4M materialized as a bomber with a wide, but streamlined fuselage, built in two halves to ease production. Such was the diameter of the fuselage that visiting German engineers from Heinkel were confused that the wide bulkhead they were inspecting was for a twin engined aircraft. The wings were built incorporating a massive integral fuel tank between the spars, with the surfaces of the wings representing the other walls of the container. These massive, but unprotected, stores contributed much to the aircraft’s enormous fuel capacity.

Much to the relief of Honjo, he was able to argue for more powerful engines, shelving the 1000hp Kinsei radials, for the new 1530hp Mitsubishi Kasei. Aside from this reprieve, the design of the aircraft was a fairly chaotic affair, as the engineers at Mitsubishi were being reshuffled between the G4M, and the A6M Type Zero fighter under development by Horikoshi Jiro’s team. The first prototype would be completed in September of 1939, and was transported from Nagoya to Kagamigahara for flight tests, as Mitsubishi lacked a company airfield at their factory. It was first flown by Mistubishi test pilot Kazuo Shima on October 23, the tests revealed some issues with handling, but the aircraft performed well. Military trials were conducted at Yokosuka in early 1940, where it was joined by the second prototype. Both aircraft impressed the Naval staff there, with the plane well exceeding the requirements placed on it, reaching a top speed of 240 knots and possessing a range of 3000 nautical miles.

Unfortunately for the design team, these impressive performance figures inspired the navy to request Mitsubishi develop the G4M as a heavy fighter. They wished to provide a long range escort to the G3M squadrons in China, which were without air cover on deep raids. There were also concerns that switching to the production of a new bomber would result in too steep a drop in G3M supplies, and reduce the complement of squadrons currently deployed. The new G6M ‘wingtip fighter’ featured a reduced fuel load and a pair of 20mm cannons in a ventral pod. In any case, the new weight distribution of the aircraft ruined the good handling of the G4M, and it simply didn’t have the performance needed. Some 30 planes were built and shelved to later be converted into transport aircraft.

Pre-production of the bomber proceeded only after the futile attempt at converting it to a heavy fighter. In December of 1940, it would officially be designated the Type 1 land attack bomber, for the Imperial year 2601. In service, the aircraft was typically referred to either G4M, or more casually as Hamaki, or cigar, in reference to the shape of its fuselage. Among Honjo’s team it bore the far less flattering nickname of namekuji, or slug.

The model accepted for service was some 520 kg heavier, and some 9 kts slower than the prototypes, after the typical design modifications were made. It too now only had a range of 2315 nautical miles once it was at a full combat load. This was, however, more than enough to satisfy the Navy. They began receiving growing numbers of the plane as pre-production began at Mitsubishi’s No.3 aircraft plant, with these 13 planes proceeding mass production. Apart from some minor leaks in the integral wing tanks, the bombers entered service without issue on April 2, 1941.

Debut in China

The next war with China escalated from a minor border dispute into one of the bloodiest wars ever waged. By 1940, the Japanese Imperial Army and Navy had pushed into the Chinese heartland, seized many of the largest and most important coastal cities, and had taken the capital of Nanjing, leaving it unrecognizable after an orgy of violence. The Nationalist Kuomintang government was, however, resolved to continue the war by whatever means. Despite Japan’s air superiority, the Chinese Air Force stayed mobile and well outside the range of Japanese fighters. They could vacate their airfields quickly and inflict heavy losses on Japan’s bombers which had been despatched against their airfields, flying great distances without fighter protection. It was with the introduction of the high performance G4M, and the extremely long ranged A6M fighter, that this strategy was to unravel.

The first G4M’s to see combat were part of the Imperial Japanese Naval Air Service’s 11th Air Fleet, formed in January in 1941. This force was composed mostly of the old G3M, but had received 30 examples of the new model bomber in July. They were to continue the aerial bombardment of many Chinese cities, beginning with Chengtu, but were soon to attempt the further destruction of the Chinese air force. The A6M fighters that had made their debut the year prior had the range to pursue targets deep within China, but were unable to hold formation with the old G3M bombers without weaving, reducing their range, and left them unable to follow them at night. However, the new G4M had a cruising speed that the fighters could match.

These two aircraft were thus essential to operation O-Go, a gambit intended to cripple the Chinese air force in some three months. The raids were launched in the early morning well before sunrise, with the bombers acting as the navigational leaders for the fighters, which kept the formation with the bombers in single-file. The force would then arrive at sunrise, to give little warning, and allow the bombers to attack as many of the grounded planes as possible, with those who were able to get off the ground being attacked by the A6Ms. The first attack was carried out on August 11, against an airfield near Ichang. The Chinese’s air force SB-2 bombers had scrambled, leaving two unserviceable planes to be destroyed, and had sent up fighters to break up the attack. To their surprise, they found fighters guarding the formation, one far more advanced than their Soviet-made I-153 biplanes. The Japanese fighters, and the gunners of the G4M’s, would claim five victories against the defenders, suffering no casualties themselves.

The operation, however, would be canceled as tensions with America and Europe had risen to the point of conflict. O-Go was suspended, but had demonstrated the long range strike abilities of the IJNAF, and the shocking capability of its long range fighter escorts. Against the bases near Ichang, the raiders had flown 47 miles further than the distance from London to Berlin. Such a feat would not be replicated until P-51B was introduced with the US Army Air Forces, and flown deep into Germany some three years later. These distances also show the long range character of the war to be fought across the Pacific, and explains the otherwise seemingly unreasonable range requirements requested by the Navy.

Setting the Board

While the Japanese invasion of China had at first been decisive, and horrifically destructive in its opening phases, their lines of communication stretched on, and the Chinese Army was growing into a more dangerous opponent. Relations with other powers with major economic interests in China collapsed, spectacularly in the case of the United States, leading to the cancellation of the US-Japan Commercial treaty. The concerns of European powers were growing too, but far less so in the face of the German-Soviet invasion of Poland in August of 1939. Meanwhile in Japan, the Navy’s ambitions were again stoked, remembering their own territorial gains of the last major war between the European powers. The most vital of these potential spoils were oil fields of Borneo, held by the forces of the now occupied Netherlands. This would grant Japan energy independence from the US, against which they had been planning an inevitable war for over a decade.

Planning and theory, however, were swept aside when the US imposed a total trade embargo in August of 1941, with the UK and Netherlands following shortly after. Rather than be an incentive to pursue diplomatic means, it instead drove the hawks in Japan’s military-dominated government to at last embark on a conflict it had long been expecting. The Imperial Japanese Navy and Army thus began working on the arrangements in what would be a rapid series of offensives across the Pacific that would wreck the American Pacific fleet before it had a chance to be mobilized, seize the vital defensive perimeter of Malaya, and oil rich colonies of the Dutch.

In regard to the land based Naval Air forces, their task would be to decimate enemy air forces before they had a chance to strike at the fleets and armies that would soon take and occupy vast swaths of South East Asia. Squadrons of G3M and G4M bombers were thus based at Formosa, to strike the American Army Airforce in the Philippines, and from what was formerly French Indochina, to assault the British forces in Malaya. Of chief importance were two targets, the Royal Navy battleship Prince of Whales and battlecruiser Repulse, which were enroute to Malaya, and the large contingent of American aircraft based in the Philippines. From the 26 of November to the 7th of December, the Japanese Navy embarked on a silent offensive, as its fleets crept toward their targets in Thailand, Malaya, Borneo, Guam, and Hawaii. Even before the war was declared, bombers were enroute to attack their targets as part of an offensive that dwarfed all others in regard to time and space.

Bombing of the Philippines

The attack force set against the Philippines was the 11th Air Fleet, which had at its disposal 81 G4M bombers and a number of the old G3M, along with a complement of 90 A6M fighters. Based in Formosa, their targets were the American Army Air Corps’ Nichols and Clark’s airfields. The American complement at these bases was considerable, numbering 35 of the new Boeing B-17 bombers, and 107 P-40 fighter aircraft, for a total of 227 aircraft, representing a very modern, and heavy strike force.

The G4Ms would however, not be the first to attack, with the air wing of the aircraft carrier Ryujo having hit positions in Mindanao, to the South, and the Army’s bombers, hitting Luzon, in the north. Thick fog had delayed the launching of the December 8th attack, and the Nichols airfield mission shifted to attack the airfield at Iba. Clark airfield remained a vital target, with two waves of G4M’s departing under the commands of Commander Suda Yushio and Lt. Commander Nonaka Taro. Commencing several hours after the Pearl Harbor attack, the commanders led the Takao and Kanoya Air Groups up to an altitude of 7000m with their A6M escorts, expecting a grueling fight to the targets ahead.

When news of the war broke out, the commander of the Far Eastern Air Force, Lt. General Lewis Brereton, attempted to launch an immediate attack against the Japanese forces in Formosa, using his in all likelihood, inadequate 35 B-17s. However, when he attempted to receive permission to launch the attack from the theater commander, General Douglas MacCarthur, he was instead held up by the General’s chief of staff, Maj. Gen. Sutherland. Unable to launch the attack, and uninterested in rebasing his bombers to a smaller airfield which he felt was unsuitable for his formation which was soon to receive further bombers, he instead kept his aircraft prepared for the attack, and sent out an early morning fighter patrol as cover.

By the time the Japanese strike force was well underway, Brereton’s fighters were turning back home to be refueled. Observers would spot the massive Japanese formation, but all attempts to warn Clark field failed, its only hope now was were its cover fighters from Del Carmen field. However, dust storms had kept all aircraft at Del Carmen grounded, and thus Commander Suda’s forces came upon a perfect target. With much of the US FEAF’s planes cleanly lined up around Clark field, the destruction was swift and overwhelming. Bombs smashed everything from the planes parked in ready positions, to airbases facilities, with the anti-aircraft batteries trying to hit the raiders using old and defective ammunition, the most recent of which was produced in 1932. Only four P-40’s were able to get airborne, and were soon lost, with the Japanese A6M fighters descending and attacking targets that had escaped the bombers. The Iba attack was equally one sided, and also claimed the only working American radar station in the Philippines. In all, both airfields were knocked out, the B-17’s were lost, and about 24 of the P-40’s were written off with many more damaged, representing a combat loss of two squadrons. The Japanese would only lose 7 planes, the only bomber lost to a landing accident on its return home.

The combined Japanese preparations, and the dysfunction of General MacCarthur’s command, had created a perfect storm that had largely annihilated the FEAF on the first day of the war. Even the staff of the Japanese Navy’s 11th Air fleet, Capt. Takahashi Chihaya believed, at the very least that, the B-17’s might have been rebased to the southern, and more defensible Del Monte airbase, which would have created serious challenges to the ongoing campaign to invade the Philippines. Few could have imagined the G4M’s strike could have been so decisive.

Force Z

While the FEAF was no longer mission capable, the next greatest threat in Southern Asia were the British garrison forces in Singapore, who were largely a responsibility of the Japanese Army, and Force Z, a pair of powerful warships dispatched weeks earlier to strengthen the British position after Japan had seized France’s Vietnamese colony. A battleship and battlecruiser, they represented a massive boost to British capabilities in the region, though the carrier support they were to receive was lost when HMS Indomitable ran aground and was laid up for repairs. Before the war had begun, these ships were merely intended to dissuade the Japanese from threatening Malaya and Singapore, as most of the Royal Navy was still tied down in Europe and the Atlantic. With the mission of deterrence gone on the morning of December 7th, the force’s commander, Admiral Tom Phillips, decided to take the most aggressive plan of action possible and attempt to thwart Japanese landing operations. Rather than choose to remain a fleet-in-being and attempt to shore up the defense of Singapore, or wait and attempt to merge with the joint Dutch-American naval forces, the Admiral gave the order to deploy his battleship, battlecruiser, and four destroyers into the sea of Siam.

It may seem foolish to have charged out without dedicated air cover, but until then, no heavy warship had ever been sunk by air attack, and he would have been out of range for nearly any other conventional torpedo bomber. The Royal Navy’s experience in Norway the previous year only reinforced this, as while German bombers had damaged several Allied cruisers, none had been lost. Beyond this, the airfield at Kota Bharu that would have supported him had been overrun by the rapid advance of the Japanese Army down the Malaysian peninsula. The Japanese Navy too had been landing marines down the coast, and when the Admiral received word at midnight December 9th that a landing force was unloading its forces at Kuantan, he set course to catch them at sunrise the next day.

As one of the Japanese Navy’s primary targets, Force Z was under considerable surveillance even before the war had begun. When they sortied on the 8th, Vice Admiral Osawa Jisaburo, the commander of the Southern Fleet, gave the Rikko units the mission to find and sink Force Z. Unable to pursue them the following day due to bad weather, the British fleet was spotted by submarine I-56 and its position was relayed to bombers. The next day, three Chutai comprising 88 planes of both the new G4M and the older G3M, launched at 06:44, to find and sink HMS Prince of Wales and Repulse. Most of the force carried torpedoes, with the 27 G3M’s carrying armor piercing bombs. Force Z was again discovered by a Genzan Air Group Rikko, and when they were joined by the bomb-laden Mihoro units, made the first attack on British warships. The attack began in a text book fashion, with a high altitude unit carrying out a level bomb attack while the torpedo aircraft made their attack runs in the confusion. 9 G3M’s dropped strings of bombs on the warships, scoring one hit, while 16 G4Ms carried out their torpedo attack. One bomb struck Repulse amidships, with the rest sending up torrents of water around the heavy warships in a shower of near misses. Some ten minutes later, the G4Ms carried out a multi-direction ‘hammer and anvil’ attack against HMS Prince of Whales, and despite the intensive evasive maneuvers, one torpedo struck the battleship on its port aft section. The explosion disabled its portside propellers and caused water to surge up the shaft into the portside engine space. With the battleship now flooding and navigationally impaired, the Japanese bombers departed, leaving the British warship in a poor state while the next attack wave assembled.

With the position and course of Force Z relayed, the assembled formation now turned to engage them, with Lt. Cmdr. Shichiso Miyauchi as formation leader. Even with the information on the position and course of the British fleet, they were still hidden by low cloud cover. When they reached the reported position, Lt. Cmdr. Shichiso spotted a seaplane launched from the HMS Repulse and gave the order to descend through the clouds. The bombers found themselves 11 nautical miles away from the British force, HMS Prince of Wales showing a list.

The Lt. Cmdr. lead the first 9 plane Chutai against HMS Prince of Wales, which in response increased its speed to 28 knots, and began veering to starboard. The second and third divisions of this force were unaware of the damage the battleship had sustained, and set course to anticipate it making an evasive maneuver to port. When this never came, they broke off and went for HMS Repulse. This left Lt. Cmdr. Shichiso’s 3 plane unit to deal the finishing blow. He ordered the plane’s pilot and co-pilot to refrain from releasing the torpedo until they were within 500 meters of the target, then his plane and the number 3 aircraft, dropped their torpedoes, the second having lost sight of the target through heavy anti-aircraft fire. HMS Prince of Wales was struck on the starboard bow, and below the bridge. Now mortally wounded, most of the formation turned its attention to HMS Repulse.

Unlike the battleship, HMS Repulse was mostly undamaged, and taking extreme evasive maneuvers in an attempt to throw off the attack of six incoming torpedo bombers. Well trained against evasive targets, the Rikko approached from both sides and all but one plane launched their weapon was released, the battlecruiser taking a hit on its port side. The plane that was unable to make its attack then turned its attention to the HMS Prince of Wales and launched its torpedo, striking the battleship on its aft starboard side.

The second Chutai, under Lt. Higashi was next, dividing its attention between stricken British warships. They succeeded in striking HMS Prince of Wales again, though failing to hit Repulse, as it maneuvered through the spread of torpedoes launched against it. The last strikes came from Lt. Haruki Iki’s Chutai, and after an appraisal of the two damaged ships, decided that HMS Repulse was the more important target. Lt.Haruki’s plane led the attack from an altitude of 30m, nearly grazing the ship as he passed it. With both of his wingmen going down in flames from anti-aircraft fire, but their torpedoes launched, Lt. Haruki’s shotai scored three hits on Repulse, with the opposing side of the attack scoring one hit as well. The order to abandon Repulse was given at 12:30 with the ship quickly succumbing to flooding, this quick decision allowing several hundred men to escape the ship before it capsized. HMS Prince of Wales went down about an hour later, taking with it Captain John Leach, and Admiral Tom Phillips.

For the Japanese airmen, only four aircraft had been lost and they had proven a decisive lesson which all Navies were quick to learn, ships without air support were in mortal danger from aircraft. While theoretically, it had seemed possible a capital ship could be sunk from the air, this was the first time two such warships had been sunk in true combat conditions. Not only had the Rikko crews proven air power was now the deciding factor at sea, but in a strategic sense they had cleared the sea of Allied capital ships from India to Hawaii, and the IJN could land troops along the coast without fear of ambush.

Lt. Haruki’s two wingmen were the only aircraft losses with fatal results, with one G3M crash landing on its return to Vietnam, and four more planes needing a great deal of repairs. On his next flight over this area, the Lieutenant dropped two bouquets over the scene of the battle.

The Attack on USS Lexington

While the Rikko enjoyed great success in the early days of the war, one encounter would prove to be a sign of the difficulties to come. In the opening weeks of the New Guinea campaign, a task force centered around the fleet carrier USS Lexington was preparing to raid Rabaul, a newly captured Japanese Naval anchorage which would prove pivotal to the Japanese thrusts into New Guinea and the Solomon Islands. Detecting the force at long range, the 4th Air Groups was given the task of intercepting it on February tenth, 1942. 17 G4Ms were sortied in two groups against the task force, but without fighter escort, as the A6M units available lacked the necessary external fuel tanks needed for the mission. Led by Lt. Cdr. Ito Takuzo, they carried an armament of bombs. Detected, and set upon by Lexington’s fighters, several of the bombers were downed before having the chance to attack their target. The remaining aircraft of both units scored no hits.

Lt. Cdr. Ito’s aircraft was badly damaged, one engine being entirely shot away by an American fighter. In their fatally damaged plane, the crew then attempted to try and fly into the USS Lexington. However, on the approach, their plane was riddled by anti-aircraft fire, and sent flying into the sea. In all, only two aircraft of the attack force were able to make it home, showing that unescorted attacks on ships with fighter cover were unlikely to succeed, and could only be made with extremely high casualties. Over succeeding campaigns, it would not be a lesson that would be taken to heart.

Battle for Port Moresby & The Bombing of Australia

While the IJN’s Fast Attack Force failed to eliminate the American Carriers in the Pacific, the loss of the American Battlefleet was a catastrophe, one that would allow the Japanese to advance swiftly through the central and southern Pacific. MacArthur would flee the Philippines, and Lt. General Arthur Percival would surrender Singapore, both after botched attempts at defending their territories. The Japanese Army and Navy would surge south, capturing rubber plantations, and the crucial Borneo oil fields. During this southern advance, the G4M would play a crucial role, in suppressing the RAF around Singapore, engaging American shipping around the Philippines, and harassing the joint American-British-Dutch-Australian cruiser force before its first, and only battle with the Japanese fleet.

With the vital resources of the Indies secured, the goal of the next phase was to build a defensive perimeter around the heart of this vast stretch of newly conquered territory. The next target was the anchorage of Port Moresby in Southern New Guinea, which if captured, would prove an excellent stronghold which directly threatened Australia. Before the carrier battle of the Coral Sea, G4M units were providing support to the amphibious landings in New Guinea. Lae and Salamaua were the first to fall in March, with the campaign continuing until the entire northern coast was held by the Japanese Navy. These operations would continue without challenge until the forces at Port Moresby were reinforced, first by a P-40 equipped squadron of the RAAF, and later by an American squadron flying P-39’s.

Against the defenders were the 4th and Tainan Air Groups.Their target was Port Moreseby itself, hoping to harass shipping and deplete the air strength of the defenders. The first major aerial engagement occurred on April 6th, where 7 G4M’s encountered five Allied fighters, surprisingly none were lost, though five returned with damage, and the loss of one crewmember. This encounter aside, the bomber units launched near daily raids against the Allied stronghold through May, even after the invasion force had been turned back after the Battle of the Coral Sea. After mid May, they sought to replenish their numbers, and returned to Port Moresby on June 16th, in support of an upcoming overland campaign by forces on the other side of the island.

The loss of the four fleet carriers at Midway sent a shock through the entire Japanese war effort, and while it was not the fatal injury, or turning point, as it commonly seen, it forced a complete re-evaluation of how the war was being fought. In the shake up, many of the Rikko were redeployed, leaving the 4th and the Genzan Air Groups to continue the offensive at port Moresby. They would continue the bombing of Port Moresby, notably sinking the Australian transport ship Macdhui on the 18th of June. Air losses to enemy fighters were fairly light, as the bombers were given a considerable number of A6M fighters as escorts, and the night raiders met no meaningful resistance. Attrition was nonetheless an issue, as the Rikko were also tasked with the double duty of maritime patrols, which saw the men and machines of these units considerably overworked. While they had not demolished the Allied air forces in the region, the landing at Buna on the opposite side of the Island had succeeded, preparing the way for the Kokoda track campaign.

Concurrent with the operations to suppress Port Moresby were the raids on the city of Darwin, Australia, and its surrounding airfields. The first of these raids were unopposed, with the Takao Air Group flying over Western Australia in mid March. Their first encounter with enemy aircraft came on the 28th, during an unescorted raid by 7 G4Ms on the RAAF base at Darwin, which sent up a number of the American P-40E’s based there. They claimed one of the bombers, which returned the next day with nine A6M’s as escort, and bombed the airfield again without resistance. Hoping to keep up the pressure, the remaining aircraft of Takao Air Group returned from their mission in the Philippines, to the new base in Celebes. There they would launch the largest raid against Darwin on April 25th, with a force of 36 bombers and 15 fighters. This time however, the formation was met by a force of some 50 P-40’s, which claimed 6 bombers. In spite of these losses, they returned the next day with a strengthened 21 plane escort, seeing only the loss of one bomber. These raids saw a brief respite in May, before the Takao Air Group again made its appearance, bombing the city of Darwin with some 27 bombers on the 13th of June, suffering no losses. Having conducted the raid from a high altitude and with a large fighter escort, the P-40’s were unable to make the intercept. Losses remained low throughout the month, but given their position and strained resources, they switched to night bombing through the rest of the year.

Nocturnal nuisance raids remained the means of attack until March of the following year when the 753 Air Group launched a new series of daylight raids against Darwin. The first, launched on March 15, saw them target Darwin’s oil storage facilities with 19 G4Ms and 26 A6M’s. With the Australian air force having been substantially built up, the RAAF sent up a number of Spitfire Mk V’s. However, while they damaged some eight bombers, they suffered terrible casualties against the large escort force, and lost at least 14 of the new fighters. The IJN continued its assault on Darwin, focusing on its airbase, which had seen considerable build up. While they were generally successful against the RAAF bases at Darwin and Fenton, the slow accumulation of losses would see the last daylight raid flown on July 6th, 1943. The campaign was largely successful, as Darwin’s ability to host any significant naval forces was gone given its continued vulnerability to air attack, and the loss of its fuel stores.

Guadalcanal

The loss of the fleet carriers Akagi, Kaga, Hiryu, and Soryu represented a grave loss for the Japanese Navy. However, it was not the decisive battle to end the war, as apart from the catastrophic loss of these ships and their airgroups, the IJN still possessed considerable offensive strength. The two most formidable IJN carriers remained, Shokaku and Zuikaku, and they were supplemented by the smaller fleet carriers Junyo and Hiyo, along with four light carriers.The IJN also retained its potent land based air arm. Against them were the American USS Enterprise, Saratoga, Hornet, and the smaller USS Wasp, along with a number of small escort carriers. While the United States could more than replace its losses the next year, if they suffered disastrous losses, like the one the Japanese Navy experienced at Midway, it could jeopardize Allied positions across the Pacific.

The area of greatest concern was the South Pacific, as while Port Moresby was still firmly in Allied hands, the Japanese Naval anchorage at Rabaul gave them control of the waters north of New Guinea. The Rabaul anchorage also proved a means of projecting force at the very edge of the Empire’s territory, which was soon to claim the otherwise unremarkable islands of Tulagi and Guadalcanal. In June, Japanese forces landed on these islands, and began the construction of an airfield on Guadalcanal. If completed, this outpost would give the Japanese Navy a powerful strategic position, allowing them to harass sea lines of communication from America to Australia. In a worst case scenario for the Allies, it could negate Australia as a position to build up forces for any major operation in the South Pacific. It would endanger the current operations to hold New Guinea, and force the main theater of the war from the Southern to central Pacific, where the Japanese Navy still held an advantage.

Before the completion of the airfield, the US Navy staged an amphibious assault with the First Marine Division going ashore on August 7th, with the support of a cruiser task force, the carriers USS Enterprise and Saratoga, and a screening force of sea planes for reconnaissance. This news came as a shock to the Japanese forces at Rabaul, with the first major response being a hastily assembled air raid of G4Ms of Rabaul’s 4th Air Groups. With such short notice, the Rikko were sent out with an armament of bombs, rather than switching to torpedoes before the 560 nautical mile flight. They flew out under the command of Lt. Egawa Renpei, a non-pilot officer, with 18 A6M fighters as escort, with one abort.

The raiders were discovered first by coastwatchers, followed by USS Saratoga’s air search radar at 11:50. F4F wildcats from Enterprise and Saratoga were scrambled to meet them at 10,000ft. They met the bombers as they lined up on the cruiser task force, unaware of the presence of the American carriers. Under some disruption from the escorts, the Wildcats claimed two bombers outright, damaging another two which were lost to ditching. The raiders failed to claim any serious damage, and returned to Rabaul to prepare for an attack the following day. The 4th Air Group sortied 17 G4Ms under the command of Lt. Ikeda Hiromi, and were joined by a further 9 from the Misawa Air Group, for a torpedo attack on the American vessels at Guadalcanal. After several aborts, 23 planes flew to the target, joined by 15 A6M fighters.

With the American carriers having eluded Japanese reconnaissance efforts, the formation thus decided to attack the forces at the Guadalcanal beachhead. There they were met with a torrent of defensive fire from the task force’s cruisers and destroyers, and several wildcats from Saratoga and Enterprise. Only one torpedo found its mark in the destroyer USS Jarvis, and Lieutenant Junior Grade Takafumi Sasaki flew his fatally damaged bomber into the transport USS George F. Elliot, with the ensuing fire consuming much of the ship. In return, American forces would end up decimating the raiding force, which returned home with only five bombers and none of its officers, which would mark the highest losses for the entire campaign. Following the battle, the USS Jarvis would be found and sunk with all hands by patrolling G4Ms, and the George F. Elliot would be scuttled, its damage being too extensive to save the ship.

The failure of the raid can be placed on the improved air defenses of American vessels, now mounting a considerable number of the 40mm Bofors guns capable of throwing out an enormous volume of fire, the presence of American fighter planes flown by aviators who had learned to fight the Zero, and also the decline of expertise of Japanese aircrews. One officer aboard the USS Astoria remarked that the Rikko of the 4th and Misawa air groups lacked the tenacity he’d seen in early battles, stating, “I’ve never seen them that bad before. Those crack Jap Navy pilots, the ones we tangled with in the Coral Sea, and at Midway–they don’t let up. Never. They come right at you, and they keep on coming until you get them or they get you. These punks–running away…”

While they had not faced the losses like the carrier based forces at Midway, casualty rates had been steady across the Southern Asian and Australian front, and the overly selective pilot training programs were now forcing these schools to rush students through to the Navy to try and meet demand. Pilots that went down in Rikko were also difficult to recover in the best cases, as their missions often took them to the limits of their own territory. In the case of the raid on October 8, 1942, those pilots who did survive took their own lives when the US Navy attempted to recover them. In the weeks to follow, many Rikko crews would refuse to bring parachutes, choosing to die, rather than bail out over enemy territory.

The day after the disastrous raid, a Japanese cruiser force would reach Guadalcanal, and in a night raid, destroy all but one of the American cruisers, and force the retreat of the amphibious forces, which had not had enough time to unload their cargo. The battle for Guadalcanal thus began in earnest, with the remote island being held by the First Marine Division against the Japanese 17th Army under Lt. Gen. Hyakutake Harukichi. Both sides were isolated on Guadalcanal, as the Japanese stronghold of Rabaul was nearly as distant as the American base at New Hebrides. The environment would prove dangerous, with malaria, dysentery, and dengue fever capable of sapping the strength of entire units, and the supply situation being so poor that some Japanese soldiers would begin calling Guadalcanal “Starvation Island”.

The Rikko would prove one of the only means of putting pressure on the now completed American airfield on the island, named Henderson for a pilot who had died at Midway. The naval air forces at Rabaul were also built up with the addition of the Kisarazu Air Group. Over the next few weeks, the assembled bombers would strike out at Henderson, with the first major raid comprising 23 planes against the airfield on August 25, suffering no losses of their own, as the American fighters were being used for ground support missions and were being rearmed when the bombers arrived. The next day, the Rikko returned with a strength of 16 planes under the command of Lt. Nakamura. Though suffering the total loss of two bombers, and two forced landings, the attack dealt a painful setback to the fledgling ‘Cactus Air Force’ at Henderson, as the bombers had torched 2000 gallons of avgas, and secondary munitions explosions damaged a number of planes. While they had escorts during these missions, the A6M’s had severe radio trouble due to their sets operating too close to the frequency of the faint radio emissions from their engine’s spark plugs. The fighter pilots typically opted to remove the troublesome sets to increase the range of their planes, but their situational awareness suffered accordingly.

 

The raids would continue on a near daily basis, apart from a diversion to chase shipping around the area. For the most part, Guadalcanal was isolated, save for fast transports and deliveries by air. The Rikko claimed one of these transports on August 30th, sinking the USS Colhoun with a pattern of bombs. Heavy raids continued into September to support the Army on the Island, which would attempt to overrun the American positions in a night assault on the night of September 13-14. Defeated, the Imperial General Headquarters would reiterate that Guadalcanal was to be captured at any cost and placed more resources towards reclaiming the island. For the Rikko, this came in the form of two more Air Groups, the Kanoya and Takao, which had both arrived by the 23rd. This allowed them to rotate out the exhausted units at Rabaul, and continue the assault on Henderson.

Henderson however, had also seen some improvements. The Cactus Air Force was reinforced by USS Saratoga’s fighter squadrons while their carrier was sent away for repairs following an attack by Japanese Submarine I-26. They also had a new SCR 270 air search radar, set up in early September. They thus had a considerable number of Wildcats, and the ability to scramble them in time to the 8 km altitude the G4M’s flew. However, the radar system wasn’t perfect and could prove sensitive to the conditions on the ground. Sustained losses among the Rabaul’s squadrons grew considerably compared to earlier efforts. Naturally, daylight raids became less frequent, though they were still occasionally conducted and would inflict serious damage. On October 11th, a Japanese raiding force of 45 G4Ms under the command of Lt. Cdr. Nishioka Kazuo, departed to Henderson amidst poor weather. Several aircraft fell out due to the weather, but the remaining aircraft split into two units. As the first unit had completed its attack, the second made its way to Henderson and caught a dozen wildcats on the ground. They would return on the 13th, with Lt Makino Shigeji leading a 25 bomber raid on Henderson, this time failing to be intercepted due to weather obscuring the coast watchers. His force would set fire to a fuel depot, and destroy a B-17 on the ground.

Night raids had begun in late August, and proceeded almost without end for a month. These were typically a single aircraft tasked with dropping a string of bombs on Henderson, with the intention of being disruptive, more than dangerous. As the conditions of the planes worsened, their engines began to grow desynchronized, leading to the aircraft making a terrible noise, earning these raiders the nickname ‘Washing Machine Charlie’. Contrary to popular myth, this sound was not intentionally created by mechanics tampering with the aircraft, the planes were simply badly worn out.

Fatigue, both of the air crews, and their equipment, resulted in the Rikko units being stood down for a time. Even with the reinforcements they had received, they had been pulling the quadruple duties of maritime patrol, anti-shipping, high altitude bombing, and night raider. From Rabaul to Henderson was about 565 nautical miles, which made for a flight time of about 6 hours. Near daily activity had rendered these units almost unserviceable.

The last major naval strike since the initial raid on the Guadalcanal came on November 12. Having detected a convoy of American ships, 19 G4Ms were sortied under the command of Lt. Cdr. Nakamura Tomo-o, who had an escort of 30 A6Ms. Led by Rear Adm. Daniel J. Callaghan, aboard the heavy cruiser San Francisco, Task Group 67.4 was primarily concerned with the presence of Japanese battleships in the area, but the air search radar on Guadalcanal informed them of an impending Japanese air attack. Detecting the force from over 100 miles away, they were able to vector a number of Cactus Air Force F4F and P-39 fighters to cover the formation.

Lt. Cdr. Nakamura brought in his formation just below the cloud cover, and after dividing his force into two units, sent them in after the American ships. As they did so, 16 American fighters rushed to intercept them. Keeping to almost wavetop height, the Rikko would attempt to press the attack while under heavy fire from the assembled American warships, and the enemy fighters which chased them frantically just over the sea. One unidentified F4F pilot went as far as resorting to ramming one of the bombers after his ammunition was expended.

Unlike the aviators that struck Repulse and Prince of Whales, many of the less experienced airmen were shaken by the volume of fire, and broke off their attacks as they closed in. None of the torpedoes hit their mark, but the pilot of one fatally damaged bomber chose to fly his plane into the USS San Francisco, rather than attempt to ditch on Guadalcanal. Anonymously, he flew his plane into the cruiser’s mainmast, the wreckage swinging over after impact, its pulverized engine and wing spilling burning avgas across the ship. The flames had spilled into the main battery director, and wrought havoc across the aft decks. In the end the fires were brought under control, but not before 22 lives were lost and further 22 were seriously injured.

Despite the Japanese aircrew having discarded their parachutes, committing themselves to death before capture over enemy territory, a number of survivors emerged from the wreckage of the low level planes. As boats were sent out to recover them, a bewildering series of encounters awaited them. One gunner aboard a floating wreck began firing on a nearby US destroyer in a very short encounter, an enraged petty officer aboard the USS Barton ignored the orders of his skipper and gunned down a dazed pilot climbing from a wreck, and one rescue team attempted to bring aboard a young airman, only to be prevented by his superior who shot him before turning the gun on himself. Of the 19 planes that were sent on the raid, only two returned to Rabaul in working order, two crews crash landed on Guadalcanal and later returned, and three others ditched in friendly territory. In all, 10 of the 19 crews were lost outright in one of the harshest engagements the campaign had seen. This all but decimated Rabaul’s attack force, leaving 3 of its 4 air groups in tatters.

Solomons

The attempts to take the island of Guadalcanal failed, with the last major land battle occurring in late October, 1942. The now wearied Japanese Army clung to the South Western corner of the Island, where destroyers acting as fast transports left oil drums full of supplies, and brought in a trickle of reinforcements. At sea, the Japanese Navy had begun the campaign with a stunning victory off Savo Island, but in the months following, had lost the battleships Hiei and Kirishima in gun battles off the coast of Guadalcanal. Yet, they had managed to sink the American carriers, Hornet, Wasp, and critically damaged Enterprise, leaving Saratoga as the only American fleet carrier in the Pacific for some time. In return, they suffered the loss of the light carrier Ryujo, and the fleet carrier Shokaku had been seriously damaged, worse though, was the loss of experienced aircrews which the Navy’s training programs were struggling to replace. These victories would not be enough without Guadalcanal, the capture of which could have proven a decisive blow against the supply lines and, crucially, morale of American forces in the Pacific.

The Imperial Army Headquarters would finally admit the loss of Gudalcanal several weeks after the end of any serious engagements on the island, on December 31, 1942. The next year would see the American forces march further north in the Solomons, where they had once only had a foot hold. For the most part, the heaviest forces on both sides were spent, and USS Saratoga was too valuable to lose. It thus fell on the cruiser and destroyer forces to continue the battle for the Solomons. For the Japanese Navy, which had suffered the loss of a number of its heavier warships, it was hoped that the Rikko could partially take up their offensive ability.

During this time, raids to support the Army in New Guinea, to inflict losses on the Allied air base at Milne Bay, and nightly nuisance raids across the theater were carried out. Major daylight raids became very rare following last year’s losses, though this isn’t to say none achieved major success. One 23 bomber raid on January 17th destroyed numerous aircraft on the ground at Milne Bay, with no losses sustained. Regardless, some tactics were sworn off as far too costly, namely daylight torpedo attack missions. The combination of improved anti-air armaments on American ships, the slow, level approach of attacking planes, and the ever more present threat of fighters, thanks to early warning radar, made daylight attacks a costly, futile affair.

A switch to night attacks brought dangers of its own, but given the high level of blind flying ability of the more veteran Rikko crews, it was far from suicidal. They would soon prove their abilities on the night of 29/30 January, after a sizable force of American warships was spotted near Rennell Island. The force in question was a task force consisting of the heavy cruisers USS Wichita, USS Louisville, and USS Chicago, the only surviving cruiser of the ill fated battle of Savo Island at the beginning of the Guadalcanal campaign. They were joined by two escort carriers, three light cruisers, and six destroyers. However, the green commander of the force Rear Adm. Robert Giffen had steamed ahead of his slower escort carriers in order to make a timely rendezvous with a number of destroyers, before reaching Guadalcanal.

Lt. Cdr. Nakamura commanded the G4M’s sorties against this fleet, comprising a mostly veteran force from the 705th Air Group, and was joined by 15 older G3M bombers from the 701st. Departing before dusk, Nakamura led the formation against TF 18. The bombers of the 705th made their attack at 19:19 hours, in dim light. The G4Ms made their attack free of interruption from enemy aircraft, but failed to score any hits. They had lost only one aircraft in the attack, which was remarkable as this battle marked one of the first uses of radar fused, proximity shells aboard American warships. At 19:38, the second force, composed of the older G3M bombers undertook their attack in darkness, with a spotter aircraft dropping a string of flares over the American fleet. The string of flares was dropped in the heading of the force, colored coded to denote the types of ships. Against the light of the flares, the 701’s planes went in. USS Chicago found itself in the sights of Lt. Cdr. Higai Joji’s flight, and after downing one of his ‘Nells’ on a torpedo run, the burning, floating wreck of the bomber now illuminated the cruiser.

USS Chicago found itself at the center of the enemy attack, with the oncoming bombers scoring two hits, one hitting the after engine space and disabling three of its four propeller shafts and flooding its turbogenerators, and another striking the forward engine room destroying the remaining active shaft, leaving the cruiser dead in the water. Swift damage control efforts set flooding boundaries and allowed the crew to save the ship for the time being. For the heavily damaged cruiser, two of Lt. Cdr. Higai’s aircrews were lost, including the veteran commander himself. However, the engagement was not yet over, as Rikko were now aware of the survival of the stricken cruiser and sought to finish it.

The task of sinking the USS Chicago lay with the 751 Air Group, a unit now composed mostly of new crews, who lacked the skills needed for the night attack the evening before. Nonetheless, they sortied 11 G4M’s under the command of Lt. Cdr. Nishioka. They found the USS Chicago under tow by the fleet tug USS Najavo at 16:10. Under escort from the other warships and F4F’s from VF-10, two of the bombers were lost before the run. However, the remaining aircraft pressed the attack and put four more torpedoes into the cruiser, with the four surviving bombers departing at as best a speed as they could make. Surveying the damage, it was immediately clear that the Chicago could not be saved, and the Navajo was ordered to cut its line. Some 20 minutes after the attack, the cruiser capsized, with the attacks having claimed 62 men. The destroyer USS La Vallette was also hit, though damage control efforts saved the ship, then taken in tow by the then available USS Navajo.

While the battle of Rennell island again demonstrated the lethality of the Rikko, it was again another sign that daylight usage of the aircraft could not be continued without significant losses. It was also indicative of a growing problem that had now reached a tipping point, one that was being felt across all of Japan’s air forces. A vast gap in ability between the fresh and veteran aircrews was not only being felt in the capability of their units, but was forcing restrictions on mission planning. The inability for new crews to even perform the same tasks as the veterans in theater would not only prevent them from embarking on the same missions together, but would leave them relegated to more dangerous missions, unable to fly under the cover of darkness.

I-Go and the Death of the Admiral

Wishing to avoid an entirely defensive campaign, Adm. Yamamoto would commit his South Eastern forces to an offensive to shore up the position of Rabaul, and its defensive circle from Bougainville to New Guinea. In this offensive, carrier air groups were based alongside their ground based counterparts for attacks on enemy shipping and air bases through the region. The Rikko, with new replacements, were to take a center role in the offensive and resumed raids against Port Moresby. Despite only modest damage being inflicted across the theater, the operation was judged a success.

It was to be entirely overshadowed by what was supposed to be a typical inspection of frontline positions. Adm. Yamamoto and members of his staff boarded a pair of G4M’s to view their positions on Balalle from the air. Not expecting to encounter any enemy forces, the pair of bombers flew to the island with a modest escort of six A6M fighters. Unbeknownst to them, American code breaking efforts had succeeded in discerning the Admiral’s plans, and 18 P-38G fighters were in route. Coming upon the flight, they ignored the fighters and went straight for the bombers before withdrawing. Overwhelmed, the escorts brought down only one of P-38’s that day, with both G4M’s being shot down.

Veteran pilot FPO1/c Tanimura Hiroaki was able to bring the second plane to the beach below in one piece, saving the lives of his crew, Vice Adm. Ugaki Matome, and Yamamoto’ chief of staff. However, the first aircraft was riddled with bullets and went down out of control, with the Admiral being struck with gunfire at the start of the attack.

The loss of Yamamoto was not the blow as it has often been remarked, indeed, he was a keen strategist, but one that had made his fare share of mistakes. His talents could never have been relied upon to salvage the then rapidly deteriorating Japanese position across the Pacific. However, the lack of a central figure with his prestige meant that the war would be directed by officers that often did not fight the war according to a single, realistic plan. The Admiral’s passing was a key point in the war, marking the definitive end of the period where a strategy was pursued with clear aims that might bring the Allies to the negotiating table. It was a purely attritional battle now, one that they were not prepared to fight, and with no plan beyond hoping to outlast their enemies.

Clinging On

With the loss of Admiral Yamamoto and the retreat from Guadalcanal, the Japanese Navy was now on the backfoot. It still possessed a number of carriers, but the quality of their aircrews had declined considerably, and the American carrier force was being introduced to the new Essex class, along with the excellent new F6F fighter. These new carriers were arguably the most capable of any class produced during the war, with 7 being commissioned in 1943 alone, a figure larger than America’s entire complement of pre-war fleet carriers.

Despite the losses borne earlier in the year, new Rikko units were deployed to bases in New Guinea and the Solomon islands, with training programs rushing to help cope with a now permanent shortage in personnel. By mid 1943, they were typically being used only for maritime patrol missions, with the Allied air presence across New Guinea and the Solomons having been considerably strengthened. Aided by the introduction of new models of fighters in the theater, like the F4U-1 Corsair, the P-40F, and P-38G, they were now ever more confident in their control of the air. They were thus able to deal serious blows to Japanese raiding forces, and were able to cover their own raiders with the long range P-38. Extremely high losses among the Japanese Naval Aviators had also seen a shift in strength across the theater that now saw the Army Air Force shouldering the majority of effort in the theater.

As the American forces climbed ever northward in the Solomon Islands, the Rikko were again called upon to help shut down their advance. Near the end of June, a major amphibious landing was threatening forces around New Georgia, and 26 G4Ms under the command of Lt. Cdr. Nakamura Genzo were sortied to attack the assembled task force. They located the fleet between Rendova and New Georgia, and found it covered by F4F and F4U fighters. Regardless, they pressed their attack with 10 bombers making their way to the fleet. They would succeed in putting one torpedo into the transport USS McCawley. It exploded in the engine room, killing 15 and cutting power to the ship, which would remain afloat until being mistakenly torpedoed by friendly PT boats later that evening. Casualties among the Rikko were again exceedingly high, with 19 planes being lost.

The American advance to New Georgia, and soon Vella La Vella, would enable them to base aircraft in a far more northern position in the Solomons. This directly threatened the Japanese air bases, Army and Navy, on the Southern and Northern ends of Bougainville, the largest and northernmost island in the Solomons. The Rikko were directed to support ground operations, bombing enemy field positions in daylight raids, and despite the considerable presence of their own fighters, casualties soon became too heavy, and after a raid on the 15th of July, were called off.

Recuperation lasted as long as September, when Allied landings along Northern New Guinea threatened the important air base at Lae, which covered oversea communication with New Guinea and the stronghold of Rabaul. The Rikko were sent to raid shipping in the area to stifle the invasion, but through the month achieved little damage. Their tactics were largely switched to anti-ship level bombing, which saw significantly lower casualties but little success, until the end of the month when desperation forced them to launch a daylight torpedo attack. Of the 8 planes sent to attack the landing forces at Finschhafen, only one returned to base with another aircraft ditching, with no hits being reported to any allied ships.

The encirclement of Rabaul had begun in earnest and it would suffer a major air raid on November 3rd, and in retaliation, Admiral Koga Mineichi would order an anti-shipping operation that would include a deployment of carrier air groups to aid their strained land-based counterparts. The Rikko would begin the offensive with a night attack on US shipping around Bougainville on November 8th. A composite flight of G4Ms from the 702nd and 751st Air Groups were committed to a night attack against the forces that had recently landed American forces on Bougainville. They would be joined by carrier based bombers in the attack, and succeeded in torpedoing the light cruiser USS Birmingham, smashing a 30 foot hole in its hull, aft of its chain locker. Regardless of a near miss from a dive bomber, a torpedo strike, and a second bomb which struck turret no. 4, Birmingham’s crew raced to stop the flooding and succeeded miraculously. In spite of the beating, the cruiser could still make a speed of 30 kts, allowing them to keep up with the rest of the formation, and avoiding the fate of the USS Chicago. Only two crewmen were killed in the attack, though many more were injured.

In spite of the cover of darkness, losses among the Japanese forces were high, with 7 G4Ms being lost. Much improved gunnery from the American ships was showing that advancements in radar direction, proximity fusing, and training, enabled them to match the feats of the night torpedo bombers. At 19:58 hours, USS Birmingham used its 5 inch gun battery to down a single G4M engaged in illuminating the task force at a range of 14,000 yards. Worse for the Rikko was that while some of the new crews were proficient enough in low light flying for night attacks, they could still find themselves overwhelmed when committing to the final run of the attack.

Rikko sorties continued the following days, with fewer losses, but also marginal success. On the night of November 12/13, the Rikko attacked Task Force 39 in 04:53 in the early morning. Three G4Ms were able to box-in the light cruiser USS Denver in a hammer and anvil attack, scoring a hit. Struck along the starboard aft engine room, Denver quickly lost propulsion and took on a 15 degree list. As damage control efforts continued, the cruiser was brought under fighter protection at six in the morning, and was able to retreat to safety. Two of the three Rikko that attacked the cruiser were shot down, with the successful strike being made by Lt(jg) Maruyama Hidezumi, whose plane returned home with 380 holes in it.

Another major attack was launched on the night of 16/17. During this sortie, SFPO Kobayashi Gintaro would succeed in torpedoing the USS McKean, a destroyer being employed as a high speed troop transport. When attempts to evade the torpedo failed, it struck starboard, aft of the rear magazine, which caused an explosion that cast burning fuel oil across much of the ship and the water around it. Sinking at the stern, the order to abandon ship was called well before the explosion of the ship’s magazines. Sixty four sailors lost their lives, along with a further 52 marines, with the survivors picked up by the other destroyers of the force.

These attacks imposed some losses against the forces invading Bougainville, but they were unable to stop the northern stream of American forces that were soon to capture the southern flank of Rabaul. Regardless of the extreme overclaiming of the Rikko crew, they were unable to deal significant damage to the amphibious forces, and were themselves taking serious losses in operations, which earlier that year, had guaranteed a good deal of safety. Eventually, the forces in Rabaul would be encircled and subjected to attack from attacks from the South and the West, before American carrier forces returned to the region in strength to deal an even greater blow. During this period, only the Rikko of the 751st remained in theater, but after a massive air raid in February of 1944, the remaining forces withdrew.

The Retreat

While 1943 lacked the intensive surface battles of the previous year, and saw no new major aircraft carrier engagements, it represented a string of serioust defeats for the Japanese Army and Navy. By year’s end, they had completely lost the ability to threaten the sea lines of communication from Australia to America, and thus any major strategic position that could threaten the ability of the Allies to continue the war in the South Pacific. Worse, they were now fighting a lost battle to retain control of Rabaul, with New Guinea being remarked as a hell on Earth from which men did not return, and their positions in the Gilbert and Marshall Islands now being reduced to the outposts of Kwajalein, Enwitok, and Truk. The central pacific strategy was also non-viable, as the American carrier forces had been more than rebuilt, and had a year to build up their air groups, now flying the F6F fighter as the fleet’s standard, which was now more than a match for the A6M. Even moresow, now that Japan’s veteran naval airmen were either lost, or rotated out. This would leave all remaining air-fleet engagements extremely one sided.

The Rikko played a minor role in defending the Gilberts and Marshalls, apart from the base at Truk. At the beginning of 1944, this anchorage would find itself under attack numerous times by American carrier forces. The greatest blow came on February 17th and 18th, when it came under major air attack. Under siege from five American fleet carriers, the operation would thoroughly wreck the Japanese Navy’s air presence in the region, and prove that the anchorage was too vulnerable for any major use in the future. While there was largely very little the forces in the region could do against the American forces, one G4M flying from Tinian would make a solo night attack against the fleet carrier Intrepid.

This single plane managed to evade attention and make its attack against the carrier. The torpedo exploded 15 feet below the waterline, causing flooding, and jamming its rudder to port. Navigationally impaired, the crew had to fashion a sail to steer the ship back to Pearl Harbor for several months of repairs.

Future attacks would take this form, as these night missions were less likely to be detected, and the pool of aviators who could actually carry out these attacks remained small. In the early months of 1944, the Rikko continued to make these attacks in piecemeal throughout the Pacific in response to the ever growing offensive on the part of the American Navy. The naval bombers also made their attacks in response to major landing efforts at Biak and Palau, while also making opportunistic bombing raids, such as one on June 5th against the airfield at Wakde island. There, a pair of G4Ms of the 753rd Airgroup destroyed six aircraft and damaged 80 more at the crowded air base, with a follow up attack hitting the base with three bombers on the 8th. However, for the most part, the effectiveness of most of these operations were indeterminate, as the scale of their operations diminished.

They also found themselves fighting more determined resistance in the air at night, as the USAAF and the Navy had advanced their own night fighter programs. Over Guadalcanal, the USAAF would first employ the P-70, a thoroughly disappointing conversion of the A-20 attack plane into the night fighter role. It had neither the speed, nor service ceiling, to catch a G4M at the 7km they typically flew during their nuisance raids over Henderson, and only one or two kills were made with this model over the course of the war. Frustrated with the P-70, Henderson resorted to using searchlight guided P-38G’s, and even modified some aircraft to carry an air search radar in a modified fuel tank. The pilot workload of the P-38G was already considered burdensome by many pilots, and the new device only worsened the situation. Greater success was found with the Marine’s converted Lockheed Ventura night fighters in the convoy defense role, but it wasn’t until the deployment of the P-61 in late 1943 that the G4Ms could effectively be pursued at night. Several dozen victory credits were tallied on the P-61, with two of the six aces made on the model being in the Pacific theater.

The US Navy’s solution to night torpedo attacks came in a more convenient form, as radar equipped models of existing carrier fighters. These were initially F6F-3N Hellcats, which placed an air search radar on the wing, which they would use in the final approach to the target after being vectored in by a supporting ship. Later models would become available, with more powerful engines, and a pair of 20mm cannons supplementing their .50 caliber guns. Marine and Naval aviators would shoot down considerably more aircraft than their land based counterparts, though fewer of them were G4Ms, with the majority being light patrol aircraft being used to track American warships at night. As was the case with American improvements in radar directed gunnery, the presence of these advanced night fighters made the Rikko’s night attack missions considerably more dangerous.

Replacement

The G4M1 Model 11 had served well past its prime, and was relieved by the improved G4M2 Model 22. The new model had Kasei Model 21 engines, which were rated at 1850 hp, with water injection. It had a new wing incorporating laminar flow research, increasing its size and fuel capacity, without increasing drag. However, it did not receive additional protection to its fuel tanks, nor did it implement anything more than token protection for its crew. Its defensiveness was somewhat improved by the installation of an additional 20mm machine gun in a powered dorsal turret, replacing the top 7.7mm machine gun mount. Later models carried the Type 3 Ku Mark 6 search radar, to allow for better target acquisition on night torpedo raids.

The old G4M1 machines were considered old and outdated, both by Americans, and the Japanese Navy itself. The airframe itself was also somewhat dated, but better engines had improved its performance, and it was being supplemented by a lighter twin engine torpedo bomber, the P1Y Ginga, or Galaxy. Nevertheless, the Japanese position in the war was irrecoverable. The Japanese assembled carrier forces would be decimated by the loss of so many airmen in the battle of the Philippine sea, and leave the navy without a coherent strategy. The battle for the Philippines would be fought without a strategy that could even hope to bring victory. Even in the planning stage, it was evident that the remaining Japanese Naval forces could not hope to prevent an American amphibious operation in the Philippines, and they would only arrive well after the invasion force had disembarked all of its forces and cargo. With no hope of actually preventing the invasion, or claiming a victory of any strategic importance, the remainder of Japan’s Naval strength was sacrificed at Leyte Gulf.

1945 was a bleak year that saw the near collapse of Japanese society. In this last year of the war, a new model G4M3 was produced, in order to serve as a host aircraft for a rocket propelled kamikaze aircraft. It reflected the futile stubbornness of those who lead the country, with the military unwilling to terminate the war until it faced a near total blockade of the home islands, the loss of the USSR as a possible intermediary for negotiating the end of the war when it invaded Manchuria, the firebombing of most major cities, and the atomic bombing of two.

Peace

In an unlikely coincidence, the G4M1 would play a role in ending the war that it had been engaged in since the first salvos. A renovated G4M1, and a transport model of a converted G6M heavy fighter, were selected to ferry the Japanese delegation to the base at Ie Shima. Under direction from Gen. Douglas McArthur, both planes were painted white, and marked with dark green capitulation crosses, so as to make them unmistakable. They also flew under the names Bataan 1 & 2, in remembrance of the first major battle between the US and Japanese Armies, and the forced march inflicted on the Allied troops.

A veteran pilot, Lt. Sudo Den of the Yokosuka airgroup, was selected to lead the delegation to Ie Shima. They departed Kisarazu on August 19th, and were joined by a pair of American B-25 Mitchells of the 345 Bomber Group, and a B-17H search and rescue plane. The trip went without issue, and Lt. Gen. Kawabe Torashiro and the other 15 delegates deplaned, and boarded a Douglas C-54, which would fly them to Manila. With the war over, they returned via the same track, but with Bataan 1 undergoing maintenance, they all boarded the G6M. In spite of a forced landing near the Tenryu river due to a fuel leak, the delegation made it home safely.

The final service of the G4M was in dispersing the remaining Rikko air and ground crew. It was on August 23 that the remaining serviceable Rikko were assembled at Komatsu. From there, the planes flew across Japan to deliver the former air and ground crews to airfields where they could make the last leg of their journeys home.

In spite of the high losses incurred by these units for much of the war, there were a number of aviators who had survived the entirety of the conflict. Perhaps the longest serving of them was Lt(jg) Tsuneo Otake, who had begun his service in the older G3M over China, before transferring to the Genzan Air Group, where he participated in the campaign over Guadalcanal until he returned back to Japan in May of the following year. From there he joined a transport squadron flying the G6M. By the war’s end he had flown 3022 sorties and accumulated 5255 flight hours. Another veteran was Lieutenant, later Captain, Haruki Iki. Capt. Iki was a veteran of the attack on Force Z, and dropped a bouquet of flowers in remembrance for those lost in the days after the battle. He was also among those who survived the war, and would go on to start an association for Rikko veterans.

Handling Characteristics and Tactics

As a design that was borne out of extreme compromises, the G4M nevertheless proved an easy aircraft to fly. It was easily controllable, even in bad conditions, and very stable, presenting a lighter workload for the pilot. Both of these would prove essential for an aircraft designed to fly over exceptionally long distances, and from bases that would be plagued with poor weather. Overall, pilots regarded the flight characteristics of the G4M as dependable. The only major drawback to the design’s airworthiness was the lack of feathering propellers, which made bringing the aircraft back a more strenuous job that required considerably more corrective flying to cope with the increased drag.

Protection was very poor. The only armor plate aboard the plane protected the ammunition for the 20mm, and was judged to be so useless that it was almost universally removed from the plane. All members of the crew were vulnerable to gunfire, which given the near universality of .50 caliber guns among American fighters, proved deadly. Worse was the lack of fuel tank protection, or self sealing containers. These aircraft were equipped with CO2 flushed atmospheres beside the wing fuel stores, and CO2 extinguishers, but these proved unreliable in combating fuel fires. Later aircraft were given rubber sheeting on the underside the wings to give some degree of self sealing protection from flak and ground fire, but provided no protection from enemy aircraft. Ironically, structurally the aircraft proved very durable thanks to its forward fuselage and wings built as a single unit. It was fairly common for aircraft to come home on one engine or in extreme states of damage, just so long as there were no fuel tank fires.

Most of the defensive guns were not particularly effective at defending the aircraft. None of the gun positions were powered, and the forward 7.7mm machine gun had a very limited angle of traverse, in addition to proving difficult to move against the air stream. The rear gunner position was the exception, and featured a 20mm machine gun. It was called a machine gun as this was a naval aircraft, and the IJN considered the 20mm a small cartridge compared to some of the others in their inventory. This weapon could seriously damage a trailing fighter, but was somewhat restricted by its use of a drum magazine, the reloading of which was quite cumbersome.

The aircraft was often called ‘Hamaki’ by its crews, over its cylindrical fuselage, though it carried a darker double meaning when the aircraft’s flammability began to become well known. Subsequent names like ‘one shot lighter’ or ‘flying lighter’ accumulated as its service continued through 1942. The official American callsign for the aircraft was “Betty”.

The aircraft was employed in many roles, as a level bomber, torpedo bomber, maritime patrol plane, photo reconnaissance aircraft, and transport. The typical combat deployment was the Kokutai, or Air Group. The airgroup itself was the Hikotai, led by its Hikotaisho, and supported by its Hikokai, which represented all of the ground based personnel and equipment, which included transport aircraft. An air group’s command staff was a distinct element, not considered part of its Hikokai. Each Hikotai comprised up to 27 planes, with an airgroup capable of fielding multiple, and not needing to be of the same model, such that some units operated both bombers and fighters. In March 1944, the Hikotai were given much broader autonomy and were capable of deploying to bases distant from their original ground based Kokutai staff and ground crew, and attaching themselves to ground based services in areas they were redeployed to.

The largest combat formation was composed of 3, nine plane Chutai, which were themselves composed of 3, three plane Shotai. In combat, these units could be broken down into whatever size formation was needed. During torpedo attacks, the shotai would be divided into their own sections and could be used to attack a target from multiple directions, preventing them from evading. At a larger level, Chutai would conduct attacks separately, waiting to see the results of proceeding attacks, before choosing and committing a target based on the damage they’d taken.

Construction

The G4M1 Model 11, was a multipurpose twin engine bomber, and was an all metal, mid wing design. Its semi-monocoque fuselage was built as two halves, joined at the 24th bulkhead for ease of construction. The forward section was built as a unified wing-fuselage section, both to increase its structural strength, and reduce weight. The rear section was simpler, and its construction was given to other firms. Structurally, the aircraft made use of ‘extra super duralumin’, produced originally by Sumitomo metals before the war. It was an exceptionally strong material in aircraft design, and an area where Japanese aviation had forged ahead of the rest of the world. Once joined, the fuselage consisted of 38 bulkheads. At the nose was a glazed section for navigation, behind which there was a flat panel in the floor for aiming the bombsight. Several windows were installed along the nose for navigation and reconnaissance purposes. The cockpit was long, containing five crew positions, and doubled as an observation platform. The cockpit was equipped with radio navigation equipment and a level autopilot. The arrangement of instruments was somewhat unorthodox, with the pilot and copilot having non-identical sets of instruments on their respective sides. Notably, the copilot’s side lacks several navigational instruments, with the intent that he likely use the central panel which does have them, in the case of emergency. The fuselage carried a centerline fuel tank, along with a trio of tanks, which were situated in the fuselage and inner wing panel.

The captain of the aircraft sat behind the pilot and copilot, and also doubled as the top gunner. The navigator sat at the rear, left side of the cockpit, with the radio operator sitting opposite him. Both of them also acted as the waist gunners in combat, with the navigator also being the bombardier. The cockpit and nose also doubled as watch stations for maritime patrol missions. The rear gunner was the only position without a secondary duty. It also was the only one with armor, with two small 5mm steel plates installed to protect the 20mm ammunition, but they were rarely kept aboard the plane.

The wings were built into the forward fuselage and were composed of an inner panel, outer panel, the engine mount, removable inner leading edges, and the flaps and ailerons. The wings were built incorporating an integral fuel tank between the spars, running from the fuselage to the end of the inner panel, with the surfaces of the wings representing the other walls of the container. These stores, combined with those in the fuselage, gave the aircraft a 4780 liter fuel capacity. External sections of 30mm rubber sheeting, installed from the 663rd plane onwards, provided a modicum of self sealing ability from punctures from below the aircraft. This added 300kg to the aircraft, reducing its speed by 5kts and reducing its range by 170 nm. The only other protective measures were flushing the compartments fore and aft of the wing tank with CO2, and adding CO2 fire extinguishers. The wings also contained a pair of two 150 liter oil tanks. The flaps and landing gear were electrically operated.

The tail section comprised a three section horizontal stabilizer featuring a center section embedded in the fuselage, connected to two outer panels. The vertical stabilizer featured a smaller, innerpanel, and a considerably larger outer panel. All of the control surfaces were equipped with trim tabs.

The aircraft was initially fitted with the Mitsubishi Kasei 11, a 42 liter, 14 cylinder radial engine which was rated at 1460hp at 2350 rpm, and had a full throttle height of 4.6km. It had a length of 1705mm and a height of 1340mm. It was replaced in March of 1942 with the Kasei 15, which incorporated a larger supercharger which improved its performance at higher altitudes. Apart from the supercharger, it was visually indistinguishable from the previous model. It produced 1420 hp at 2350 rpm, and had a full throttle height of 6km. Both used direct fuel injection and were equipped with a single stage, two speed supercharger, with the Kasei 15’s being far larger. Initially, there were only two exhaust stacks, but later models included one exhaust stack per cylinder.

Armament

The G4M1 had a bomb bay which could accommodate 800 kg of munitions. The bomb bay did not have retractable doors, but rather a removable fairing that was carried on the aircraft for reconnaissance, transportation, and ferry flights. The bomb load could consist of a single 500kg bomb, four of 250 kg bombs, twelve 60 kg bombs, and a variety of other devices, such as parachute flares, and target marking smoke. They were configured to use the Navy’s bombs, and with few exceptions were unable to make use of the weapons for Imperial Army aircraft. The suspension methods between the two forces differed, and their fuses were not interchangeable without the use of an adapter.

As with other Japanese torpedo attack aircraft, the G4M1 carried the Type 91 torpedo. This weapon was produced in a number of marks going back to 1931, though wartime stockpiles and production were the Models I, II, and III, possessing a common diameter. These had a diameter of 45 cm, and were powered by an eight cylinder, wet-heater type, radial steam engine. The Mod. It could carry a 150 kg warhead out to a range of 2 kilometers at a speed of 42 knots. The Mod. II, a 205 kg charge out to the same distance, with the Mod. III carrying a 240 kg warhead. The Mod.III also possessed an interchangeable warhead, allowing it to be converted to a Mod. IV, 300 kg, a V-Head 305 kg warhead, a Kite head at 355 kg, or the Mod.VII at 420 kg.

The bomber was equipped with three 7.7 mm Type 92 machine guns, and a single 20mm Type 99 machine gun. The Type 92’s were modernized variants of the British Lewis gun, being a gas blowback machine gun with a cyclic rate of 600 rounds per minute, and loaded from 97 cartridge pan magazines. The 20mm machine gun was an Oerlikon FFL adapted for an aircraft mount. It was an advanced primer blowback weapon with a cyclic rate of 490 rounds per minute. It could be loaded from 45, 60, or 100 round drum magazines. The 100 round magazines were a late war addition. The machine gun enclosures were two part blisters where the rearward half could be pulled inside the aircraft. The rear section was a conical frame that articulated to move with the position of the 20mm gun. By late 1942, it was commonly modified in the field by removing the rear half of the enclosure to give better visibility and field of fire. Later, it was redesigned to incorporate a rear cone with a framing that was less restrictive.

Production

The G4M1 model 11 was produced at Mitsubishi Airframe Works No. 3 at Nagoya, with production beginning in 1940, with the completion of a single aircraft. Production picked up the following year at a low rate, peaking at 28 aircraft per month in December with 182 made during the year. Monthly production increased the following year, with around 30 planes being produced per month, with 39 being produced in December. 1943 production sat at roughly between 45 and 60 planes being produced per month, being produced alongside its replacement, the G4M2. Production of the G4M1 terminated in January of 1944, with a total of 1170 aircraft built, excluding the two prototypes and the abortive G6M1 project.

No.3 works fabricated the airframes and skinning for all of the aircraft built there, though other items including electrical components, instruments, wheel assemblies, rubber parts, pumps, and calves were supplied from other manufacturers. Conscripted labor began to be used early in the production of the G4M1, with conscript workers appearing in October 1941. The factory operated in two 11 hour shifts, with one hour and ten minutes in breaks for lunch and smoking. In addition to the G4M1, the plant was concurrently producing the A6M fighter ‘Zeke’ or Type Zero, the J2M ‘Jack’, and the F1 ‘Pete’ recon seaplane. Production of the G4M1 model 11 was terminated in January of 1944. It was superseded by the G4M2 Model 22 which replaced it on the production line.

There exists no documented variants of this aircraft, regardless of the model of engine or other modification, the aircraft was always referred to as G4M1 Model 11.

Mitsubishi G4M1 Model 11Specification

Engine	Mitsubishi MK4E Kasei 15 (early models used the Kasei 11)
Engine Output	2x1420hp ( 2x1460hp)
Empty Weight	7000kg
Operating Weights	8810-13300kg
Maximum Range	2315 nm
Maximum Speed	252 knots at 4200m (without rubber wing sheeting)
Armament (payload limited by space not weight)	4x 7.7mm Machine Gun, 1x 20mm Machine Gun, 800kg payload
Crew	Pilot, Copilot, Navigator/bombardier, Radio operator, Commander, Rear Gunner
Dimensions	–
Length	19.97m
Wingspan	24.88m
Wing Area	78.12m^2

Conclusion

The G4M1 was perhaps the perfect material representation of the philosophy and martial attitudes of those who led Japan to war. It was an aircraft built entirely to suit the most aggressive plans possible, with little consideration given to its use outside of its, admittedly, broad focus, or a changing wartime environment. It was an excellent aircraft in prosecuting a war that had been meticulously planned, and was to end very quickly. Yet, this wasn’t the war Japan was to fight, instead finding themselves facing a flexible, and determined adversary with superior material and technical resources. In this shift, the compromises that made the G4M1 a deadly, long range weapon, became serious liabilities that threatened the usefulness of the aircraft. While the virtue of self-sacrifice was paramount to the Japanese military, it was to prove self destructive when the lives of experienced airmen far exceeded that of the aircraft they flew.

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Credits

Written By Henry H.

Edited By Henry H.

Illustrated by Oussama Mohamed “Godzilla”

Sources:

Primary

G4M1 Model 11 Manual

Japanese Aircraft Performance and Characteristics TAIC Manual No. 1. Technical Air Intelligence Center. 1944.

Mitsubishi Heavy Industries, Ltd (Mitsubishi Jukogyo KK) Corporation Report No. 1 (Airframes and Engines). United States Strategic Bombing Survey Aircraft Division. 1947.

The Japanese Aircraft Industry. United States Strategic Bombing Survey Aircraft Division. 1947.

USS Chicago (CA29) Loss in Action 29-30 January 1943 Guadalcanal Island. Buships War Damage Report No. 36.

TM 9-1986-4/TO 39B-1A-11. Japanese Explosive Ordnance (Bombs, Bomb Fuzes, Land Mines, Grenades, Firing Devices and Sabotage Devices. United States Government Printing Office.

Japanese Air Weapons and Tactics. Military Analysis Division. 1947.

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The Cactus Air Force Air War Over Guadalcanal. Eric Hammel & Thomas McKelvey Cleaver. 2022.

Neptune’s Inferno The U.S. Navy at Guadalcanal. James D. Hornfischer. 2011.

Fire and Fortitude The US Army in the Pacific War 1941-1943. John C. McManus. 2019.

Mitsubishi Type 1 Rikko ‘Betty’. Osamu Tagaya. 2001.

Profile Mitsubishi G4M ‘Betty’ & Ohka Bomb. Rene J. Francillon Ph.D. 1971.

American Nightfighter Aces of World War 2. Andrew Thomas and Warren Thompson. 2008.

Conquering the Night Army Air Forces Night Fighters at War. Stephen L. McFarland. 1998.

Japanese Aircraft of the Pacific War. Rene J. Francillon Ph.D. 1970.

Sunburst. Mark R. Peattie. 2001.

Kaigun. Mark R. Peattie and David C. Evans. 1997.

McCawley II (AP-10). Naval History and Heritage Command.

Birmingham II (CL-62). Naval History and Heritage Command.

Denver II (CL-58). Naval History and Heritage Command.

McKean I (Destroyer No. 90). Naval History and Heritage Command.

Intrepid IV (CV-11). Naval History and Heritage Command.

USS San Francisco (CA38) Gunfire Damage Battle of Guadalcanal 13 November 1942. War Damage Report No. 26. 1942.

Lt(jg) Haruki Iki Imperial Japanese Navy (IJN), Kanoya Kokutai (Kanoya Air Group). Pacific Wrecks.https://pacificwrecks.com/people/veterans/iki/index.html