Japanese Military Innovations in World War II

When it comes to military innovation, during and leading up to World War II the Empire of Japan was absolutely on the cutting edge. In terms of weapons for the army, there was not much that was very remarkable from Japan which tended to lag behind the other major powers in tanks and heavy weapons that were the latest trends in military technology. However, it made up for that by surpassing all others in terms of air and naval warfare innovations, possessing the best naval aircraft and the best torpedo at the start of the war by all accounts. Still, for the Imperial Japanese Army, while weaponry may have been lacking, innovation in strategy and skilled leadership was certainly not. One need only consider the fact that such major world powers as the United States and the British Empire both suffered their worst military defeats at the hands of Japan in the early days of the war. When it came to the latest in military weaponry, tanks, aircraft, naval aviation and submarine technology, Japan certainly had the most difficulty when it came to tanks. In border clashes with the Russians in Mongolia, the Japanese suffered severe setbacks even though, especially at that time, the Russians themselves were far from being up to the standard of other powers in terms of tanks. Japan was hampered in this regard by never fighting an enemy in which armored combat was really essential. The Chinese never fielded much of a challenge in that regard and the attacks on Southeast Asia were made against colonial powers that were already engaged in a fight for survival in Europe and they had no tanks to defend these colonies and most had only token military forces designed to maintain law and order rather than repel a determined invader. Still, in some of the island battles it became clear that some answer had to be made to the rugged and reliable American M4 Sherman and by the end of the war Japan did develop some tank types that would have posed a challenge, such as the Type 3 Chi-nu. However, it was produced so late in the war that it was reserved to defend the home islands against an invasion that never came so that none were tested in battle.

On the sea and in the air, however, things were very different. The Japanese were absolutely on the cutting edge of developing military aircraft. The famous Mitsubishi A6M Zero fighter, mostly used in naval aviation but which was ground-based as well, was regarded by both Axis and Allied countries as the best carrier-based fighter in the world at the time. In the early weeks and months of the war, the Japanese Zero shot down 12 Allied planes for every one of their own lost. It gave Japan a marked advantage over anything the British or Americans had on hand to use against it. The only problem was that, once the war began, it became extremely difficult for Japanese industry to keep up as American fighters continued to improve. However, the biggest loss was in pilots. The most successful fighter pilots of the war, after the Germans, were the Japanese, the most successful being Lieutenant Hiroyoshi Nishizawa who, even by the most conservative of statistics, shot down far more planes than the best British, Russian or American pilots. An expert Japanese pilot in the latest aircraft proved to be capable of victory even against enemy forces that were considerably superior in number. The problem was that so many of these expert, remarkably well trained pilots were lost at the disastrous Battle of Midway that Japanese naval aviation was never able to recover. Pilots simply could not be trained and new planes designed and manufactured fast enough to keep up with what the war effort demanded.

Yokosuka "Ohka" rocket plane

However, it was the Japanese who proved the real value of naval aviation and the centrality of the aircraft carrier in modern warfare. As mentioned, they took a lesson from the British raid on Taranto, but not many others did. Too many military leaders around the world regarded Taranto as a fluke, a case of the British being lucky and later felt satisfied when it was shown that the damage to the Italian fleet had not been quite as extensive as was first thought. However, after the overwhelming, stunning, Japanese victory at Pearl Harbor (the worst defeat in the history of the United States Navy) no one could ignore the results. The innovative military thinking of Admiral Isoroku Yamamoto had been vindicated dramatically. Japan also developed, during the war, the Kawanishi N1K “Strong Wind” interceptor that proved more than a match for the American “Corsair” or “Mustang” and at least a match for the famous F6F “Hellcat”. However, it was impossible to produce these in sufficient numbers for them to have much of an impact. Production quality was also a problem for the Nakajima Ki-84 “Gale” fighter but when it was properly built, had good quality fuel and an expert pilot it was an extremely effective aircraft and was capable of such high speed (nearly 400mph) that it was able to intercept the B-29 Superfortress bombers. Using technical data supplied by Germany, Japan also had several designs for jet aircraft by the end of the war but they were too late to see service. Now, even if one were to discount these craft because none were completed and they were based on German technology, Japan developed craft independent that were very similar. Probably the most famous was the Yokosuka MXY7 “Cherry Blossom” (Ohka) which was a rocket-propelled suicide plane. Its speed was so great that it was virtually unstoppable in its final attack and forced the US Navy to re-organize their anti-aircraft defenses. They did not have much of an impact, as a suicide-weapon it was a weapon of desperation but showed how far “outside the box” Japanese military designers were able to go.

The one area where Japanese innovation stood out more than any other, and so much so that it really requires very little in the way of explanation, was in naval warships and submarines. Already pioneers in the utilization of aircraft carriers, the Imperial Japanese Navy pushed the boundaries of military technology for both traditional warships and in new fields such as the submarine fleet. The problem was that most of these never had the chance to really engage in the sort of battle for which they were intended. Nonetheless, the designs were positively astounding and some have never been surpassed even to this day. Undoubtedly the most famous Japanese naval vessel of the war was the battleship Yamato, though its sister ship, Musashi, was probably even more formidable. These were, quite simply, the largest battleships ever built and will probably always remain so. They were built as part of the thinking of the Japanese naval high command which was focused on a major, decisive, battle such as was won by Admiral Togo at Tsushima in the war against Russia. With these two monster warships, Japan was confident of being able to totally dominate any ship-to-ship engagement with any navy in the world.

super-battleship Yamato

The problem, of course, was that such a battle never came about, partly because of Japan’s own victory at Pearl Harbor which largely decimated the American battleship force. The US struck back with aircraft carriers and submarines and the two huge battleships remained in port, protected from such threats, for most of the war. However, they did finally come out to do battle, when the odds were irreversibly stacked against Japan, at Leyte Gulf. Coming under attack from the air, as opposed to from enemy surface ships which she was intended to combat, the Musashi was finally sunk but only after enduring an unbelievable 17 direct bomb hits and (believe it or not) 19 torpedo hits at the Battle of Leyte Gulf in 1944. The Yamato went out in 1945 on a suicide mission against US forces at Okinawa and was likewise sunk by American carrier planes but likewise it took no less than 7 direct bomb hits and being struck by 10 torpedoes before the massive ship went down. There was a third such ship planned but during construction it was decided to turn it into an aircraft carrier rather than a battleship and the result was the Shinano, the largest aircraft carrier in the world and the largest warship of any kind ever built up to that time. Unfortunately for Japan, it was sunk by an American submarine before it ever launched a single aircraft in combat, which at least goes to show that the cautious attitude towards the Yamato and Musashi had been justified.

Japan also broke plenty of records under the water as well. No one was as innovative as Japan when it came to submarine design, though Japanese boats were so poorly utilized that they never came close to scoring anywhere near the success that Germany or Italy did. This was partly due to an over-ambitious strategy combined with overly-cautious tactics (which meant few ever got the opportunity to score many victories) but also because of the level of innovation itself which resulted in Japan producing so many different types of subs that none were able to be mass-produced in the numbers needed to have any appreciable impact on the war effort. Nonetheless, Japan produced highly advanced boats that demonstrated immense creativity and technical know-how. One area Japan was famous for was in combining air power with submarines. Many Japanese subs were equipped with small scout planes that could be launched and recovered from the sub itself to serve as reconnaissance aircraft. One even took up a few incendiary bombs which were dropped on the west coast of the United States. However, as the war situation became more desperate, many subs were forced into carrying cargo to isolated, starving garrisons on the islands of the south Pacific.

super-submarine I-400

It is all the more remarkable though, given how Japanese subs were never used to their full potential, that some still did manage to pull off incredible successes. For example, in the Battle of Midway, Lt. Comm. Yahachi Tanabe of the I-168 daringly steered under a screen of US destroyers to sink the aircraft carrier USS Yorktown and the destroyer USS Hammann. Even more incredibly, Tanebe and his crew then managed to survive the ensuing counter-attack and evade the US warships to return damaged but intact to Japan. Most famous of all was Lt. Comm. Takakazu Kinashi of the I-19 who, on September 15, 1943, scored the single most successful submarine attack in history when one salvo of torpedoes took down the aircraft carrier USS Wasp, damaged the battleship USS North Carolina and sank the destroyer USS O’Brien. In terms of boat designs, Japan produced the super-streamlined SenTaka class boats which actually had a higher underwater speed than even the most advanced late-war German Type XXI, making them the fastest submarines up to that time and which were also extremely deep-diving. However, they came too late to see action. Similarly, Japan produced the very famous SenToku class boats, I-400, I-401 and I-402 which were massive ‘double-decker’ submarines equipped with three Seiran bombers. Originally intended to be used for surprise bombing raids against Washington and New York they were later planned for an attack on the Panama Canal but the war ended before they reached their target. These had a longer-range than any submarine in history, giving them more endurance than any sub before the nuclear era and they were the largest submarines ever built up until the launch of the American nuclear ballistic missile submarine USS Benjamin Franklin in 1965. In fact, some of the early American missile subs were probably based off of the I-400 design.