The problem with making comparisons between each country's machines is that we have access to information today that the designers or intelligence personnel could not have had back then. Before the war there wasn't very much sharing of intelligence, although it did happen. A few European aircraft manufacturers including Britain shared technology with Japan, but after that country's increasing militaristic stance and its invasion of China, those countries, with the exception of Germany shied away from Japan as an ally. This meant that it received technological assistance from Germany, but it developed its own eco system of design and supply of military equipment that existed in something of a bubble, isolated from the rest of the world, which was deliberate, of course. The Japanese military industrial complex model was different to Europe and the USA, which notably resulted in a unique approach to aircraft philosophy, design, manufacture and influence.
Before we lean too heavily in the direction of the Japanese workforce producing crude and less sophisticated designs, that simply wasn't true. Investigation of Japanese aircraft designs during the war prove this as a fallacy. I have yet to read one that criticises the production values of Japanese aircraft. Yes, things like engine power and armament lagged behind the west, but that was a matter of resources and an internal government and industry deficiency in the appreciation of the evolving battlefield and their reluctance to address it, rather than a lack of sophistication and ability.
The Mitsubishi Zero is a classic example of this entire scenario. The Zero was finely designed and built and technologically was a match for its carrier based contemporaries in terms of technological advance and performance back in 1939/1940 when it went into production and service. It had modern systems, flaps, retractable undercarriage, cannon armament when none of its contemporaries did, intricate design features, such as its means of entry into the cockpit for the pilot, for example, a series of retractable pegs to avoid the pilot standing on the wing root. These pegs sat flush with the fuselage side, and extended when a lever was pulled, which in turn sat flush with the aircraft fuselage. These pegs retracted into the fuselage and had small mushroom shaped inner ends, this was because where they retracted into was kept a floatation bag that deployed automatically when the aircraft ditched. The mushroom ends ensured the packed bag did not get punctured by the moving pegs.
The pegs extended.
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The entire aircraft was cleverly and sensibly designed, and when an analysis of its design is made, it compares favourably with its contemporaries as an entirely modern, well designed and constructed aircraft. That it outlived its usefulness and was kept in the frontline far longer than it should have been, thus exposing its deficiencies, which were not apparent when it was first introduced, was not the aircraft's doing, but the naval high command's fault. Focus was taken away from its replacement on carriers, not to mention the Japanese naval high command believed their own hype surrounding the aircraft for far too long, and steered its designers toward land based interceptors rather than carrier based ones following extensive carrier losses at Midway. The Mitsubishi A7M, Horikoshi's intended A6M replacement suffered delay after delay and because of mounting defeats as the war wore on Japan's industry simply could not keep up with the evolving strategic scenario, so the poor Zero stayed on amid a scramble to produce anything that matched what the West was fielding.
Read this report for a good insight into the design produced by a US aviation publication during the war.
Japan's fate was linked to Germany's - it simply could not match US manufacturing and logistical might and Allied technical knowledge sharing, it had nothing to do with technological inferiority. The Imperial government's lack of appreciation of what it had got itself into was disastrous and ultimately led to Japan's defeat on the many battlefields it was engaged on, regardless of how bloody they were. As with all dictatorial regimes, there was a detached reality between what was happening on the intelligence summaries the masters read every morning and what was happening on the battlefields. Japan's soldiers were fierce, loyal and determined, but their masters failed them by grossly underestimating the US/Allied resolve, manufacturing capability and sharing of technology.
Japanese industrial structure also hampered its war effort. The Army and the navy had its own industrial bases, factories, plant, such as steel mills and so forth, and so, like Nazi Germany, backstabbing, undermining the opposition and outright subterfuge to curry favour with government institutions hampered the overall industrial output, long after the Allies had figured out that total war required working together on a scale that was previously unheard of. Japan lost because of this, as did Nazi Germany, for that matter. Both failed to realise that the very systems they operated under were detrimental to their own war effort.
The sharing of technological advance and resources between the USA, UK and their Allies was unprecedented in history. The Axis powers never reached such heights to the same degree. A handful of jet engines via U-boats to Japan and what have you doesn't match anything like the exchange of equipment that went around the globe from the USA and to a lesser extent Britain. Had Japan's separate naval and army industries worked together, things might have taken longer for the Allies to defeat Japan and those weapons and aircraft that we regard as inferior probably would have been more on a par with what the West was producing, but let's be clear, this lack of capability by comparison with Western aircraft and engines does not indicate a weakness within the Japanese technical know how, but a weakness within Japanese appreciation of the strategic situation. The country's engineers and designers were as capable as those anywhere else, its just they were let down by the unique set of circumstances that Japan existed in, not technological inferiority.
Understanding this places Japan's technological output into context. Japan had the knowledge, it had knowledge of and even implemented some of the same advances the West made on its aircraft, such as superchargers, armour plating, self-sealing fuel tanks, greater engine capacities and so forth, but much later than the Allies, simply because they didn't have the same intel network and willingness to share information among its industry for the greater good. As previously mentioned, a lack of appreciation of the evolving strategic situation and the unique Japanese wartime environment defeated its engineers, which actively hindered the entire nation's technological progress. The ideas were there, though.