“In the field of machinery the Japanese mind is at a peculiar disadvantage. They are able to turn out an exact copy of any mechanism that comes into their hands, but the type of mechanical imagination which went into its original creation—which, for want of a better term, is sometimes known as Yankee ingenuity—they are at a loss to duplicate.” 

In the lead up to, and during the Second World War it seems the US was all too willing to believe its own propaganda on Japanese industrial prowess, and although official intelligence material never descended to the level of the drivel quoted above (from ‘Mechanix Illustrated’) it did repeatedly assume that all Japanese aircraft were copies of Western types. Whilst this was broadly true in the twenties, American Intelligence never noticed (or possibly cared) that the Japanese had attained parity with (and in some areas surpassed) the West by the latter half of the 1930s. This attitude was so ingrained in American thinking that a Western aircraft needed to be conjured up for any new Japanese type to be a copy of (try finding the aircraft that the Kyūshū J7W 震電, ‘Shinden’ (Magnificent Lightning) was copied from: you will struggle). This is particularly evident in the psychological effect the Mitsubishi Zero had on its foes in 1942, an effect only multiplied by the lens of racism through which the Japanese people were inevitably observed. This was followed by a weird scramble to find what American aeroplane the Zero was copied from (Spoiler alert: it wasn’t). It should be noted that extreme racialism and racism was also institutional in Imperial Japan, where the official line often pushed was the notion of the Japanese as a supreme master race.

Join us as we take a look at some other masterpieces of Japanese indigenous design, whether conceived when the Empire swept all before it, or suffering the crushing reality of total defeat.

10. Mitsubishi Ki-83 

キ83 (Ki 83)

Produced by a team under Tomio Kubo, who also designed the superlative Mitsubishi Ki-46, the Ki-83 could have been the finest twin-engined fighter of the war. As things turned out it became an obscure footnote in aviation history.

The result of an Imperial Army specification calling for a high altitude, long-range heavy fighter the aircraft that emerged from Mitsubishi’s experimental workshop was possibly the most aerodynamically clean radial engined aircraft ever built and possessed spectacular performance. As well as recording the highest speed attained by any Japanese aircraft built during the war, the Ki-83 was blessed with remarkable agility for such a large aircraft and was fully aerobatic at high speeds. It is recorded to have been capable of executing a 2200 feet loop at 400 mph in 31 seconds. Compared to its direct US equivalent, the F7F Tigercat which also failed to see meaningful service during the war*, the Ki-83 had the same range but was faster and more manoeuvrable. Armament comprised the potent combination of two 30-mm and two 20-mm cannon, all firing through the nose. Unfortunately for this superlative warplane, its timing was appalling. 

First flown in November 1944, tests were often interrupted by American air raids and of the four prototypes known to have been completed, three were damaged or destroyed by bombing. The crippling raids by B-29 Superfortresses were also the reason that the Ki-83 never entered production: despite the enthusiasm of both the Army and Navy, by the time it was flying all aircraft manufacturing was focused on interceptors to combat the B-29 and the Ki-83 never received a production order. After the war the sole surviving prototype was evaluated in the US and received glowing praise. With the higher octane fuel available in America the Ki-83 ultimately recorded a speed of 473 mph. Despite being earmarked for preservation the only Ki-83 to survive the war and arguably the finest wartime fighter produced in Japan was last recorded at Orchard Field Airport in Illinois in 1949. It is presumed to have been scrapped there in 1950.

*The first operational F7F sorties took place on 14 August 1945, the war ended the following day.

The Ki-83 made our list of the ten best aircraft of World War II that failed to see service.

From this angle the small window in the fuselage for the optional second crew member is visible just above the tailplane. The outlet at the rear of the nacelle is the turbocharger exhaust.

9. Mitsubishi Ki-15 

九七式司令部偵察機, Kyunana-shiki sireibu teisatsuki (Army Type 97 Command Reconnaissance aircraft)

雁金, ‘Karigane’ (Wild Goose)

Although outclassed fairly quickly, the racily art-deco styled Mitsubishi Ki-15 was a brilliant harbinger of what the Japanese aviation industry was capable of and was the first Japanese aircraft to appear in Europe when in 1937 a single example owned by the Asahi Shimbun newspaper, named ‘Kamikaze’ (before that word had any sinister connotations and considered “delightfully named” by ‘Biggles’ creator WE Johns in ‘Popular Flying’), flew from Tokyo to London for the coronation of George VI.

Despite much of the press coverage of this flight turning out to be predictably obsessed with the racial make-up of the Kamikaze’s crew, a process made all the more fun for reporters by the fact that navigator Kenji Tsukagoshi was half British (though attempts to find at least one European parent for pilot Masaaki Iinuma to ‘explain’ his aerial proficiency proved fruitless), a few reports managed to notice that the aircraft was a totally indigenous design, such as British publication ‘Flight’ which reported: “Contrary to expectations, this Mitsubishi monoplane… and its engine do not appear to have built under direct licence from any American firms” but very few pointed out that the 51 hour, 17 minute, 23 second flight over a distance of 15,357 kilometres occurred without any mechanical trouble at all and at a speed unattainable by virtually any contemporary military aircraft. Just to put the icing on the cake, after a whistle-stop tour of major European capitals, Iinuma and Tsukagoshi flew all the way back to Japan in four days, again with no mechanical issues. Given that a mere three years earlier most of the entries into the MacRobertson Air race to Australia had broken down or crashed or taken an insanely long time to reach their destination due to short range and running repairs, this sort of thing should have acted as a sharp wake up call to Western observers (but didn’t).

The less peaceful version of the Ki-15 was utilised as a reconnaissance and light attack aircraft in the Second Sino-Japanese war, being arguably the first truly modern combat aircraft to see service in that theatre, and in developed form during the opening stages of World War II, when its speed was still good enough to render it difficult to intercept, thus setting a precedent for the superlative Ki-46. 

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8. Mitsubishi A6M 

零式艦上戦闘機, rei-shiki-kanjō-sentōki (Type 0 Carrier-based Fighter)

零戦 ‘Rei-sen’ (Zero Fighter)

“I look like Robert de Niro, I drive a Mitsubishi Zero” sang Billy Bragg on his 1991 single ‘Sexuality’, a rare namecheck for a Second World War aircraft in the realm of late 20th century popular music, and although Billy Bragg looks nothing like Robert de Niro and obviously never having sat in, let alone ‘driven’ a Mitsubishi Zero, the very presence of this most famous of Japanese aircraft lends an effortless cool to the song that the inclusion of, say, a Vickers Vildebeeste or a Brewster Buffalo would fail to impart. 

The Zero was one of the greatest aircraft of all time, the only Japanese aircraft to be commonly referred to by its official designation by both sides in the Pacific (the odd name ‘Zero’ derives from the last two digits of the Japanese year 2600, during which it entered service and the official allied reporting name ‘Zeke’ never entirely caught on) and the idea of leaving it out of a Top Ten of Japanese aircraft is ludicrous, let alone a Top Ten of Japanese WWII aircraft. However, unlike such aircraft as the Spitfire, the Zero failed to be developed sufficiently to remain in the vanguard of international fighter aircraft and was essentially a spent force by 1945, despite being produced in greater numbers than any other Japanese aircraft before or since. Nonetheless, for a period of two years or so it was, without doubt, the most psychologically shocking aircraft in the sky and the most advanced carrier fighter in the world.

The fact that the Zero caused such a stir amongst the Allies is perplexing: the aircraft had appeared over China well before Pearl Harbor and was a known quantity amongst Chinese aviators and, perhaps more pertinently given the majority if its future foes, the US personnel of the American Volunteer Group (the famed ‘Flying Tigers’). A captured Zero was in Chinese hands as early as February 1940 and was flown and inspected by an American team who sent a highly detailed report to Washington. This report appears to have been filed before it was read as the overriding response to the Zero’s capability once Allied fliers met it in combat was horrified surprise. But the Zero was, after all, immediately preceded by the Mitsubishi A5M which Western observers seemingly failed to notice was the first cantilever monoplane carrier fighter in the world. 

Everything You Always Wanted to Know About Soviet World War II Combat Aircraft (but were afraid to ask) here

Despite the suggestion of a swathe of American types that the Zero was alleged to be a copy of, it was, of course, a superlative example of indigenous design led by the brilliant Jiro Horikoshi. Its specification was so challenging that Nakajima didn’t even enter a rival tender: they deemed it impossible to meet. As it turned out, Horikoshi had to use a brand new aluminium alloy (‘Extra Super Duralumin’) which had only been developed by Sumitomo in 1936 to be able to make the Zero light, yet strong enough to fulfil the speed, range and manoeuvrability requirements. The Zero was utterly dominant from its appearance in 1940 to the latter end of 1942, remaining a dangerous opponent to the war’s end in the hands of an experienced pilot. Unfortunately for the Japanese, experienced pilots were in desperately short supply for the latter part of the conflict due to the horrific attrition of the Pacific war. But for two glorious years, if you were Japanese at least, the Zero reigned utterly supreme over land and ocean.

7. Mitsubishi Ki-67

四式重爆撃機, Yon-shiki jū bakugeki-ki (Type 4 Heavy Bomber)

飛龍 ‘Hiryū’ (Flying Dragon)

On the whole, Japanese bombers of WWII were not a particularly inspiring bunch. The Navy’s Mitsubishi G4M for example, whilst boasting a beautifully streamlined airframe and spectacular range, was prone to burst into flames if on the receiving end of merely a smouldering glance. The Army’s Nakajima Ki-49, the immediate predecessor of the Hiryū, though less overtly flammable, was disappointing: its bombload meagre and although intended to operate without an escort, its survival was anything but assured against any modern fighter. The sparkling performance of the Ki-67 therefore comes as something of a surprise and the Army were utterly delighted with it.   

It should be noted that the contemporary Japanese definition of a ‘heavy’ bomber was not the same as that of other nations and the Ki-67 would have been described as a medium bomber in any other air force. Furthermore its published bomb load and range of 1,070 kg and 2,800 km respectively don’t sound that brilliant when compared with, say, the earlier B-25H Mitchell which could carry more than 2,000 kg and fly 2,170 km. However, published figures even today seem determined to maintain contemporary Allied propaganda in that, whilst not exactly a lie, they suggest the B-25 is better than it actually was, as it could either carry 2,000 kg or fly 2,170 km, not both, the range quoted was only possible with a much reduced load. The Ki-67 on the other hand was quite capable of flying 2800 km with its 1,070 kg bomb load. It could also do so at a speed the B-25 could only dream of and possessed an agility unmatched by any other medium bomber. The Hiryū was not only the finest bomber built by Japan, it was also one of the best aircraft in its class worldwide. So impressive was its performance and manoeuvrability that it was developed into a fighter, a seemingly insane development process as what other aircraft considered a heavy bomber has ever been adapted into a fighter?* The Ki-109 which entered limited production was ridiculously heavily armed with a 75-mm cannon in the nose and intended as a B-29 interceptor but its ceiling was insufficient to attack the high-flying Boeings.

Far more successful in its original intended role as a bomber, the Ki-67 had the misfortune to emerge into a world where Japanese forces were everywhere being pushed back and assailed by vast quantities of Allied aircraft. The Hiryū saw considerable action during its relatively brief service, attacking the US 3rd Fleet off Formosa (now Taiwan) and the Ryukyu Islands and later being used at Okinawa, in China, French Indochina (now Vietnam) Karafuto (now Sakhalin) and against B-29 airfields on Saipan and Tinian. Once the Japanese high command had accepted the use of humans as a missile guidance system in the form of the kamikaze the Ki-67 was used as a basis to develop this approach to its depressingly logical conclusion, the Ki-167 桜団 ‘Sakura-dan’ (Cherry blossom), ‘special attack’ bomber, which carried a 2.9 tonne thermite shaped charge in a large dorsal fairing intended to destroy fortified positions when crashed into them (in tests the charge proved capable of destroying a tank from a distance of 300m, simply through the power of directional blast). Details of the Ki-167’s production and use are obscure and although records are missing, there is photographic evidence that the aircraft definitely existed. It appears that around five examples may have attempted operational missions, thankfully none of these horrific machines ever hit an enemy target, being either shot down or lost to technical issues. An ignominious end to the career of an outstanding aircraft.

*Yeah yeah, the B-17 (kind of).

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6. Kawasaki Ki-100

 五式戦闘機, Go-shiki sentouki (Type 5 Fighter)

Few fighter aircraft in history have made a successful switch from an inline powerplant to a radial (or vice versa) but one of the finest examples of this rare breed was the Ki-100 and its existence was very much a case of force majeure rather than any considered process. The Ki-61 飛燕, ‘Hien’ (Flying Swallow’) from which it was derived was a fine fighter, noted by Allied pilots after its appearance during 1943 for its unusual toughness compared to previous Japanese fighters. As usual, Allied intelligence scouted around for whatever western type the Ki-61 was a copy or licence-built version of and thought maybe it was something Italian, due to its superficial resemblance to the Macchi MC 202, this apparently informing the choice of its reporting name: ‘Tony’. To be fair, in this case they were half right as the Ha-140 engine of the Ki-61 was in fact a licence-built Daimler-Benz DB 601. Unfortunately for Kawasaki, engine supply had never kept up with airframe production, and even if it had, the Ha-140 was proving highly troublesome in service. So much for German technical prowess. By December 1944, 200 engineless Ki-61 airframes were stored in the open at Kawasaki’s factory at Kagamigahara and the situation became totally untenable after a B-29 raid on the Akashi engine plant on 19 January 1945 effectively ended production of the Ha-140. This added considerable impetus to ongoing work to re-engineer the Ki-61 to accept the radial Ha-112 engine, which was in relatively plentiful supply and possessed much better reliability. 

Reflecting the desperation of Japan in the last year of war, the conversion of the first Ki-61 to receive the Ha-112 took place in just seven weeks. The new engine was nearly twice as wide as the inline Ha-140, possessed a different thrust line and was 45 kg lighter. Takeo Doi, chief designer of both the Ki-61 and Ki-100 was not keen on the engine change and expressed doubt that the conversion would be successful but in the absence of any viable alternative the work went ahead. Kawasaki followed the same process that Hawker in the UK had earlier followed in the radial engine Tempest II and (ahem) ‘based’ the engine mounting on that of the Focke-Wulf Fw 190. The resulting aircraft exceeded even the most optimistic expectations of the design team and utterly vindicated the decision to re-engine: although marginally slower than the Ki-61, the new Ki-100 could outclimb and outmanoeuvre the previous fighter. Tested against a captured P-51C Mustang the Ki-100 was found to be slower but much more manoeuvrable and could out-dive the American aircraft. Given pilots of equal ability, a dogfight would always favour the Ki-100 – though it was admitted the P-51 could break off and escape at will. Against the F6F Hellcat, the Ki-100 was believed to be superior in every regard.

The Top 10 US Navy aircraft of World War II here.

Sadly for Japan, the Ki-100 only entered service in April 1945 but did see enough service to be considered the most reliable of the Japanese Army’s fighters. In combat, when flown by experienced aircrew (of which few were left by spring 1945), the Ki-100 proved formidable. On 3 June 1945 for example, the 244th Sentai claimed seven Corsairs destroyed and in a huge dogfight with a large formation of Hellcats on 25 July, 12 F6Fs were claimed shot down. It is hardly surprising that the Ki-100 was highly popular with pilots, what is totally remarkable is that the entire career of the Ki-100, from design conception to final surrender took place in a mere 10 months. 

5. Aichi D3A 

海軍九九式艦上爆撃機, Kaigun kyuukyuu shiki kanjou bakugekiki (Type 99 Carrier-based bomber)

Though the Ju 87 Stuka remains the archetypical dive bomber of the war, it performed most of its deadly work on land. The D3A was the preeminent Axis dive bomber at sea, sinking more Allied warships than any other Axis aircraft and was the first Japanese aircraft to bomb an American target when the Aichi craft spearheaded the attack on Pearl Harbor. 

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Aichi was a watch manufacturer that decided it was time to get into the aviation field in the 1920s and throughout the interwar years it maintained a close partnership with Heinkel, despite the terms of the Treaty of Versailles forbidding German military aircraft research or production. However, the Japanese delegate on the League of Nations inspection team charged with monitoring this situation simply told Heinkel in advance when they were coming and Heinkel made sure nothing illicit was ever found when they visited: a most satisfactory arrangement for all concerned. The Heinkel influence is clear to see in the D3A with its beautiful elliptical wing, closely related to Heinkel’s own He 70 ‘Blitz’. By the time of the Pearl Harbor attack, the D3A was a proven combat aircraft, having been in action over China for two years beforehand, but the Allies once again decided that this Japanese dive bomber was of no huge concern even as German dive bombers were delivering psychologically terrifying precision strikes across mainland Europe.

Proving that psychologically terrifying precision strikes were not the preserve of the Luftwaffe alone, the D3A opened its WWII account at Pearl Harbor, where admittedly all the ships were conveniently stationary. It then followed this up by sending three US destroyers to the bottom in February and March of 1942 and causing havoc amongst Royal Navy shipping in the Indian Ocean during April, culminating in the sinking of HMS Hermes, the world’s first purpose-built aircraft carrier. During the Indian Ocean raid, D3As achieved hits with 80% of their bombs, against manoeuvring ships at sea which was an incredible success rate. These post-Pearl Harbor attacks were conducted solely by the D3A but most of the successful strikes carried out by the Aichi aircraft were conducted in concert with the Nakajima B5N torpedo bomber, in exactly the same way that the Curtiss SB2C Helldiver would later ride roughshod over Japanese shipping in concert with the Grumman TBF Avenger torpedo bomber.

The glory days for the D3A were very much the initial two years of the war, when the surprising agility and adequate performance of the Aichi dive bomber saw it utilised as a fighter aircraft on occasion but the inexorable improvement in Allied fighters saw the D3A gradually outclassed by its enemies, despite the introduction of the aerodynamically improved D3A2. The much faster Yokosuka D4Y 彗星, ‘Suisei’ (Comet) took over the dive bomber role from late 1943 onwards by which time most of the fleet carriers had been lost, along with veteran Japanese aircrew, and the D4Y could never repeat the remarkable success of its forebear. Yet even once totally outdated the D3A could still inflict terrible damage on its enemies: a D3A sank the American destroyer USS William D Princeton as late as 10 June 1945 in a kamikaze attack.

4. Kawanishi N1K-J 

紫電, ‘Shiden’ (Violet Lightning)

The Japanese kept converting heavy bombers into fighters and charming newspaper-owned monoplanes into attack aircraft so it should come as no surprise perhaps that the Navy’s finest landplane fighter of the war should have derived from a seaplane. There were several instances of floats being added to WWII fighters to create a waterborne combat aircraft, the Spitfire, F4F Wildcat, Fiat CR.42 and even the Blackburn Roc were all subjected to this process for example, though only the Zero would see combat in its floatplane form (as the Nakajima A6M2-N). The N1K-J was the only fighter to apply the process in reverse when the float was removed from the powerful N1K1 強風, ‘Kyōfū’ (Strong Wind) floatplane fighter and replaced with wheels to create the N1K-J Shiden. The resulting aircraft, though essentially a lash-up, proved faster than the Zero and had a better range than the J2M Raiden interceptor and was thus rushed into production.

Compromised by the mid-wing configuration of the Kyōfū, intended to keep it clear of spray, the initial N1K-J required unusually long landing gear which were the source of much trouble but in the air the aircraft proved exemplary, demonstrating an excellent turn of speed and a truly remarkable manoeuvrability, boosted by a mercury switch that automatically measured angle of attack and extended the flaps during turns, a system known as the ‘combat flap’. A redesign to eradicate the N1K-J’s most obvious flaw, its mid-mounted wing, saw the aircraft appear in a low-wing configuration as the N1K2-J 紫電改 Shiden-Kai (Kai meaning ‘modified’) with a simplified and lightened structure that consisted of fewer parts and could be built in fewer man hours whilst boasting improved performance. Unfortunately, B-29 raids on the Kawanishi factories meant that only 415 of the improved variant were produced compared to 1007 of the original N1K-J conversion. Both types were somewhat compromised by the intermittent reliability of the Nakajima Homare engine but there was no obvious alternative and the same issues were plaguing other Japanese aircraft. In combat, when the engine was running properly, the Shiden proved formidable, even against the latest Allied fighters. On one occasion for example, the Corsairs of VFM-123 were surprised by Shidens which were mistaken by the US pilots for Hellcats, and a 30-minute aerial combat ensued. Three Corsairs were shot down and another five were damaged while three other F4Us were so badly damaged they were dumped at sea after recovering on their carrier. The Corsairs claimed 10 Japanese aircraft destroyed, but in reality no Japanese aircraft was lost to the F4Us. The reputation of the Shiden was also somewhat magnified by its role as the sole equipment of the 343 Kōkūtai, formed on 25 December 1944 as a particularly unwelcome Christmas present for the Allies. This unit was formed of the Navy’s most experienced surviving fighter pilots, such as Saburo Sakai and Naoshi Kanno, and was equipped with the finest aircraft available. Even during the chaotic conditions prevalent over Japan during 1945, the 343 Kōkūtai exacted a considerable toll from the enemy and the N1K2-Js of the unit remained the equal of any Allied fighter they encountered until the end. 

3 Kawanishi H8K 

二式飛行艇, Ni-shiki hikōtei (Type 2 Flying Boat)

The Pacific during the Second World War was the largest battlefield in history, yet all but a tiny fraction of it was water. As a direct result the flying boat was of particular value in this huge watery realm, and the best flying boat fielded during the conflict was the Kawanishi H8K, which was the most heavily defended and fastest flying-boat serving with any of the combatants, and remained so until the end of the conflict. In 1929, Kawanishi sent a technical team to the Short Brothers company in the UK, then acknowledged as a world leader in maritime aircraft design (and, perhaps more importantly, a major shareholder in Kawanishi). After building a few examples of the Short Rangoon under licence, Kawanishi mass produced the large and efficient parasol winged H6K which boasted an incredible range, allowing it to undertake unrefueled patrols of up to 24 hours in duration. Unfortunately the H6K was also slow and vulnerable to fighter attack. The H8K was an altogether more formidable machine and represented the greatest technological leap in this kind of aircraft ever achieved. 

Designed under a team led by Shizuo Kikuhara, the H8K featured a deep and slender hull and shoulder wing. The hull initially gave serious trouble, the prototype being prone to severe porpoising and the spray thrown up by the bow completely inundated the two inner engines. On one occasion the spray was so bad that the propellers were damaged. Careful redesign, conducted in concert with hydrodynamic scientists from the University of Tokyo eliminated these issues and the H8K’s hull was the most efficient fitted to a flying boat during the war. 

As well as performing the same maritime patrol, reconnaissance, and anti-submarine work as contemporary flying boats of other nations, the H8K was also expected to carry out additional offensive tasks as a torpedo carrier and bomber. In the latter role, the H8K was intended to operate in concert with supply ships at which they could refuel and arm, effectively giving them a transoceanic range. The H8K was employed in exactly this fashion in the opening weeks of the war when on 4 March 1942, only a month after it entered service, two H8Ks attempted to bomb Pearl Harbor in a follow up strike after the famous attack in December. Refuelled at sea by two submarines, the flying boats’ target was the oil storage depot at the naval base but cloud cover over the target resulted in the failure of this audacious mission, the bomb load was dropped without being aimed and exploded harmlessly. Nonetheless the H8K’s impressive range allowed it to bomb the United States fleet at Espiritu Santo Island as well as Jaluit Island, the Shortland Islands, and the Phoenix Islands, distances of up to 1,850 km (1,150 miles) and up to 18 hours duration. In addition, reconnaissance missions were undertaken along the Australian west coast, culminating with the bombing of Broome aerodrome by an H8K on 17 August 1943, the aircraft contributed to the sinking of seven US submarines, and it was developed as an effective transport aircraft, though bad luck due to weather struck again when an H8K2-L carrying Vice Admiral Koga Mineichi, Yamamoto’s successor as Commander in Chief of the combined fleet, flew into a typhoon and was never seen again.

Unlike most other Japanese aircraft, the H8K was considered a difficult target for Allied flyers. It was fast (for its size), rugged, well armoured, and well protected possessing a highly innovative fire suppression system for its huge fuel tanks. It was also fearsomely well armed, with the most produced variant, the H8K2, bristling with five(!) 20-mm cannon and five 7.7mm machine guns. Offensive armament was similarly in advance of its peers, the H8K could carry two Type 91 torpedoes or up to 2000 kg of bombs or mines. The only advantage the H8K did not possess however was numbers, production was painfully slow and after B-29 attacks commenced on the Japanese mainland, was dropped completely so that Kawanishi could concentrate on production of the Shiden-Kai fighter. By war’s end only four examples still existed in broadly airworthy condition. One of these was taken to the US where its hull design heavily influenced that of the postwar Martin P5M Marlin, the last US military flying boat. Meanwhile, Kawanishi, prevented from building aircraft by the Allied occupation switched to general engineering, was renamed Shin Meiwa in 1949 (building cars under the Daihatsu name from 1951) and eventually returned to flying boat construction with the PS-1 which entered service in 1971 and flies to this day, a direct successor to the mighty H8K. 

2 Nakajima Ki-84 

四式戦闘機, Yon-shiki sentō-ki (Type 4 Fighter) 

疾風 ‘Hayate’ (Gale)

Built for an offensive that had stalled by the time it appeared, the Ki-84 barely ever fought the kind of campaign that it had been designed for but even during the chaotic conditions attending the death throes of the Empire that created it, the elegant Ki-84 managed to demonstrate a performance that was as good as the world’s best.

The Ki-84 was conceived in the happier times (for Japan) of early 1942. The Japanese Army and Navy and their respective air arms were trouncing any force that attempted to oppose them but the appearance of superior allied fighters was realised to be only a matter of time. The Army’s standard fighter at the time was the Nakajima Ki-43 隼 ‘Hayabusa’ (Peregrine Falcon), officially the 一式戦闘機, ‘Ichi-shiki sentōki’ (Type 1 fighter), an aircraft in the A6M Zero mould, utilising a relatively low powered engine, light structure and low wing loading to deliver almost unbelievable agility at the expense of more or less all other attributes. This had been supplemented by the Nakajima Ki-44 鍾馗 ‘Shoki’ (Demon queller), the 二式単座戦闘機 Ni-shiki sentō-ki (Type 2 fighter), a dedicated interceptor that focussed on maximum speed and dispensed with the fixation on agility displayed by all other Japanese fighter aircraft and was thus regarded as too specialised to be regarded as a successor to the Ki-43. A fighter that combined the best features of both designs was sought and the Ki-84, designed by Yasumi Koyama, was the brilliant result, the finest Japanese fighter aircraft to see service in large numbers during the conflict.

Top Italian aircraft of World War II here

On its combat debut in China during the Japanese offensive of August 1944, the Ki-84 enjoyed a situation that would not be repeated: facing the US 14th Air Force which was critically low on fuel and supplies, the first unit to receive the Hayate was the 22nd Sentai, formed of highly experienced pilots most of whom had been part of the Hayate service trials unit and were therefore well versed in the qualities of their aircraft. The poor build quality that would afflict the Ki-84 later in its career had yet to appear and the aircraft created quite the impression on its foes. Here was an aircraft that displayed all the virtues of earlier Japanese fighters but possessed none of their shortcomings. It was fast, powered by the lusty 18 cylinder Nakajima Homare with water-methanol injection and delivering 2000 hp at take-off; well armed with two 13-mm Ho-103 machine guns in the fuselage and two 20-mm Ho-5 cannon in the wings; tough: featuring self-sealing fuel tanks and armour protection, both previously largely absent from Japanese fighters; and manoeuvrable: on its debut the Ki-84 could outclimb and outmanoeuvre any Allied aircraft then in service. Intended from the outset as a multi-role combat aircraft, the Ki-84 featured hardpoints for up to a 250kg bomb under each wing and was utilised as a highly effective fighter bomber, notably during the fighting in Okinawa.

It couldn’t last of course, Allied bombing and blockades took their toll on Japanese industry and Nakajima was no exception. Forced to rely ever more on unskilled labour such as students (and having been a student, I know the lowly standards, slapdash approach, and desperation that this implies), whilst dealing with an ever lower quality of raw materials and components, the build quality of the beautiful Ki-84 began to suffer. By early 1945, standards were so lax that individual Ki-84s exhibited seriously differing performance. Hydraulics failed, the Homare engine proved troublesome, undercarriage legs even snapped on landing due to incorrectly tempered steel. At the same time, the old story of combat attrition saw the quality of Japan’s fighter pilots inexorably dwindle. Nonetheless, a Ki-84 in decent shape gave even a mediocre pilot a fighting chance against the ever-increasing hordes of excellent Allied aircraft, and at least there were plenty of them: the Hayate was the most numerous Army fighter by early 1945.

Testing of a captured Ki-84 at Wright Field in the USA, highly impressed American pilots and technical staff. Despite noting that “very little effort has been made to make the pilot’s job easy or safe”, the report highlighted the “unusually strong” construction and states “the handling and control characteristics of the aircraft are definitely superior to those of comparable American fighters” concluding that the aircraft “may be compared favourably to the P-51H and P-47N” which is praise indeed given that the P-47N was barely operational before VJ-day and the P-51H failed to enter service before the war’s end, yet the test aircraft was a fairly early Ki-84. Part of the reason for this spectacularly good showing was the superior fuel available to the US testers with a higher octane rating than that the Ki-84 was expected to consume in service. Decent fuel considerably improved performance (the captured example clocked 427 mph at 20,000ft whilst the official Japanese top speed at the same height was 388 mph) and eliminated any concern about the reliability of the Homare engine. Noted British test pilot Eric Brown was similarly impressed, comparing the Ki-84 favourably against the Griffon powered Spitfire Mk XIV and stating it was the finest Japanese aircraft he flew. Had it been available earlier, before the industrial rot set in and all the best pilots were dead, the magnificent Hayate could have been a very significant problem for the Allies indeed.

1 Mitsubishi Ki-46 

一〇〇式司令部偵察機, Ichi rei rei-shiki shirei-bu teisatsu-ki (Type 100 Command Reconnaissance Aircraft)

Reconnaissance aircraft seldom get the attention they deserve, performing totally essential work, usually alone and often unarmed. In the Ki-46 the Japanese possessed the world’s finest example of this type of aircraft. As a reconnaissance platform it was unmatched by any other machine until the appearance of the Mosquito and proved maddeningly difficult to intercept throughout the conflict. As late as September 1944, a Spitfire Mk VIII (itself no slouch) required the removal of armour and a pair of machine guns to achieve the performance necessary to effect an interception. According to an oft-repeated claim, the Germans were impressed enough that they attempted to obtain a manufacturing licence (without success), though a reliable original source for this tale remains elusive. If this is true however, it paints the Ki-46 in a remarkable light, for the race-obsessed Nazis to admit that a superior aircraft was built by an ‘inferior’ people was praise indeed. What is not in doubt however, is the fact that the Ki-46 was the only Japanese aircraft deemed of sufficient interest to be sent to the Soviet Air Force technical institute in 1945 for further evaluation. Even the Japanese Navy, who detested the Japanese Army and everything to do with it, were forced to concede that the Ki-46 was superior to any aircraft they themselves possessed and used it for missions over New Guinea and Australia. 

Curiously however, the Ki-46 programme started with the decidedly unimpressive Ki-46-I. Despite the Japanese aircraft industry being exceptionally good at streamlining radial engines (and the Ki-46 was possibly the finest exponent of this trend) the Ki 46-I handled poorly, failed to meet performance estimates and was used largely for evaluation and training. An engine change to the Mitsubishi Ha-102 featuring two-stage, two speed supercharging transformed the aircraft and when the Ki-46-II entered service in July 1941 its performance rendered it immune from interception. Throughout 1942 and 43, the Ki-46 swanned about in near perfect safety, with only an occasional unlucky or careless example falling to Allied fighters. The Ki-46-II was built in the greatest numbers of any variant and remained in service until the end of the war by which time its performance advantage had diminished somewhat but was still potent enough to allow it a decent chance of survival in Allied controlled airspace which was more than could be said for most Japanese aircraft from mid-1944 onwards.

The improved Ki-46-III was faster still due to a weight reduction programme, the adoption of more powerful Ha-102 engines with direct fuel injection, and a revised fuselage design resulting in near perfect streamlining. In this form it could achieve a maximum speed a shade over 400 mph. 654 examples of the Ki-46-III were built, a total that would have been higher but the combination of bombing and an earthquake at Mitsubishi’s Nagoya factory crippled production. The development of a replacement aircraft, the Tachikawa Ki-70, resulted in an aircraft with inferior performance and as a result the Ki-46 was improved further to become the turbo-supercharged Ki 46-IV. Although it never entered production due to the difficulty of manufacturing the turbochargers, its performance was incredible: in February 1945 two of the prototypes flew from Peking to Yokota in 3 hours 15 minutes, covering 1,430 miles at an average of 435 mph. By contrast the cruising speed of the contemporary, and much vaunted, Mosquito PR Mk XVI was 318 mph and its absolute maximum 407 mph. Loved by its crews and respected by its enemies, the Ki-46, designer Tumio Kubo’s masterpiece, was for most of the war in a class of its own.

Correction: the initial variant of the Shiden was the N1K1-J, not the N1K-J.