Aviation-Centric Combined Fleet

Chapter 12 - Shiden

Around the beginning of 1936, shocking news hit the Imperial Navy, which was vigorously transitioning from the doctrine of big-gun battleships to aviation-centric warfare. It was reported that the US Army Air Corps had initiated the development of long-range bombers, specifically four-engine heavy bombers. Considering that the Imperial Navy was already progressing in the development of four-engine flying boats, it was not surprising that the United States would consider building four-engine heavy bombers. In terms of aviation, the United States was far more advanced than Japan. Moreover, being a nation with significantly greater national and economic power than Japan, the US could easily afford to deploy an ample number of expensive four-engine heavy bombers.

Perhaps sensing a similar sense of crisis, the Imperial Japanese Army also showed great interest in this matter and, in collaboration with the Imperial Navy, launched an investigation. Military attaches and spies to various countries, including the United States, were mobilized, and after nearly six months of investigation, it was confirmed that the information regarding the development of four-engine heavy bombers was highly credible.

If the US were to acquire four-engine heavy bombers, it was certain that the recently deployed A4N carrier-based fighter, not to mention the in-development Experimental Type 9 single-seat fighter, would be inadequate to handle them. Both the A4N and the Experimental Type 9 single-seat fighter were armed with only 7,7 mm machine guns. It was clear that even against twin-engine bombers, not to mention four-engine heavy bombers, their firepower was insufficient.

In a panic, naval aviation officials hastily formulated the specifications for an interceptor focused on countering large bombers and instructed manufacturers to develop it. However, major manufacturers like Mitsubishi and Nakajima were already overloaded with various projects, including fighters, reconnaissance planes, bombers, and attack aircraft. Therefore, the Imperial Navy, partly to leverage the expertise of Kawanishi in seaplane construction, instructed them to develop the Experimental Type 12 interceptor. For the Imperial Navy, the Experimental Type 12 carrier-based fighter was the main focus, and the Experimental Type 12 interceptor was seen as a long shot, with expectations limited to potential success and gains if any.

However, thanks to Kawanishi's enthusiasm, the completed prototype exhibited surprisingly high performance. For the engine, they had opted for the Kasei engine, which had been developed ahead of schedule. This decision aimed to reduce costs and facilitate maintenance and supply by using the same engine as the Experimental Type 12 land-based attack bomber and the Experimental Type 13 carrier attack bomber.

At the time of the directive for development, there were no suitable large-caliber machine guns available, so they reluctantly equipped the prototype with six 7,7 mm machine guns for the time being. However, in the event that the 12,7 mm machine gun in the final stages of development or the already decided upon 20 mm autocannon were adopted, they planned to promptly replace the 7,7 mm machine guns. The requirements were focused on high-speed and high-climbing performance, with no detailed restrictions imposed on other aspects.

Perhaps this decision was a stroke of luck. The interceptor created by Kawanishi exceeded the expectations and hopes of naval aviation officials.

Compared to the A4N and the Experimental Type 9 single-seat fighter, the Experimental Type 12 local had more than double the engine output and triple the firepower. Although it conceded the honor of being the first domestically produced fighter with a 600-kilogram-plus weight to the Army's Ki-44, which began development slightly earlier, it surpassed it in turning and dogfighting performance. It was confirmed that the Experimental Type 12 local interceptor possessed sufficient performance not only in anti-bomber combat but also in dogfights against enemy fighters.

Eventually, after further refinement, this aircraft was officially adopted in 1940. Originally, the Experimental Type 12 interceptor should have been named the "Zero" based on its adoption year. However, the Experimental Type 12 carrier-based fighter had already taken that designation. In that case, there were suggestions to name the Experimental Type 12 carrier-based fighter the "Type 0 carrier fighter" and the Experimental Type 12 interceptor the "Type 0 land-based fighter." However, the latter name did not sound appealing at all. Due to this, and unusually for the Navy, it was decided to secretly solicit a nickname. In light of the aircraft's sharp acceleration and deadly armament, it was aptly named Shiden, meaning a sharp light emitted from a polished blade.

This Shiden would undergo significant transformations over time through engine upgrades, weapon enhancements, and the addition of an automatic aerial combat flap. Additionally, a seaplane version of the Shiden, equipped with Kawanishi's characteristic floats, would be adopted a year later under the name "Type 1 seaplane fighter." This version would later be commonly referred to as Kyōfū, but that's another story.