It’s the infamous and destructive wars throughout each century of history that are responsible for so many of today’s technological advancements. Of course, along the way to the invention and perfection of modern weaponry, there were quite a few weapons that didn’t make their way into future warfare.
Such was the case of the Kaiten, a torpedo invented and used by Japan in the last months of World War II. However, it wasn’t technology or weaponry advancements that ended the Kaiten’s existence – it was the ultimate death of the soldiers who controlled the Kaiten.
The Kaiten wasn’t like any other torpedo in use during World War II. These submarine torpedoes were manned by soldiers in the Imperial Japanese Navy, who drove these suicide craft right into their enemies. It was a weapon created to shake the enemy to their very core, its name chosen because it meant “the heaven shaker” or “the turn toward heaven” in English.
When the Japanese military felt they were losing control – and their chances of winning the war – they turned to the Kaiten, despite its high human price.
As 1943 came to a close, signaling yet another year of the second world war, the Japanese high command began exploring new options to secure victory for their troops. Military officials recommended using different types of suicide craft – Kamikaze planes, Kaiten submarine torpedoes, Shinyo boats, Fukuryu suicide divers, and even human mines were all options considered by the Imperial Japanese Navy.
Although initially rejected, the high command decided they were the best option for success in the first months of 1944, and the Japanese Special Attack Units began developing prototypes of the proposed human weapons. The first research on a potential Kaiten began in February 1944, and a prototype was developed by July 25 of that year.
The Kaiten submarine torpedo proved successful – in fact, it ranks second to Kamikaze planes in the effectiveness of Japanese suicide craft. Just one week after the first prototype was created, the Imperial Japanese Navy placed an order for 100 torpedoes. Those early Kaiten were simple, little more than a Type 93 torpedo engine connected to a cylinder in which the pilot would sit, directing it via limited electronics and steering.
Of course, in order to ensure the Kaiten could inflict damage, it required testing – and Lieutenants Hiroshi Kuroki and Sekio Nishina were the guinea pigs. Both knew they would die in the process, via either failure or success, like so many soldiers to come.
A total of six different models of Kaiten were designed, though five never saw combat. Initially, the first models were designed to eject their pilots once the torpedo began accelerating towards the final target; however, not a single test pilot attempted to escape, and it solidified its role as a suicide weapon.
In later models, the pilots were locked inside and unable to exit even if they desired – however, the pilots were given a self-destruct button, allowing them to kill themselves and the torpedo should their attack fail.
When the Kaiten finally entered the war after its brief test period, it quickly saw action. Pilots had its controls down: Kaiten would launch off of a host submarine, loaded with one pilot in each torpedo’s cockpit, aimed towards a specified target. Once in range of that target, the pilot brought the Kaiten to the surface, making any final adjustments necessary to make an impact.
Finally, the pilot and Kaiten submerged, warheads armed and ready as the torpedo sped into the enemy vessel. If a torpedo and its pilot failed, a second run would be attempted – if that, too, failed, the pilot then hit that self-destruct button.
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