The number of casualties suffered by both the Allied Forces and Japanese during the island invasions of Okinawa and Iwo Jima are a good indicator of the potential bloodbath that awaited Bill and the other troops, air, and navy personnel had Operation Downfall, the planned invasion of Japan been necessary. The invasion of Okinawa cost the Allies over 50,000 casualties. The Japanese suffered more than 200,000 casualties, about half military and half civilian. At Iwo Jima 21,570 Japanese military personnel died. Only 216 were taken off the island alive as POW’s for a death rate of over 99%. Allied casualties, over 26,000, were more than twice that of the D-Day landings. By any objective measure a massive invasion of Japan would have dwarfed the Pacific Island landings.
The plan for the final defense of Japan was called “Ketsu-Go.” The most frightening aspect of the plan was the extensive use of suicide units. The planned suicide operations dwarfed the Kamikaze (divine wind) attacks on Allied naval forces made during the Pacific Campaign. As a part of Ketsu-Go the Japanese were building 20 suicide take-off airstrips in southern Kyushu in addition to 9 seaplane bases to be used in suicide missions as well. In Korea, Western Honshu and Shikoku there were 58 additional airfields to be used for massive suicide attacks. Despite their losses the Japanese still had almost 13,000 aircraft of all types with many being designated for Kamikaze operations.
In addition to airplane attacks, the Japanese had developed other forms of suicide operations. These included the “Okka” — a rocket-propelled bomb, much like the German V-1, but piloted to its final destination by a suicide pilot after being catapulted out of caves in Kyushu. Following the suicide air assaults the Japanese defense called for attacks on allied troop carriers by 300 two man Kairyu suicide submarines, packed with a 1,320 pound bomb in the nose. If the attacking troops succeeded in getting through these defenses they would face the Kaitens-human manned torpedoes over 60 feet long, each carrying a warhead of over 3,500 lbs. and capable of sinking the largest American naval vessels. These were to be used against our invasion fleet just off the beaches and were particularly feared by our navy because they were difficult to detect. If this failed to stop the attackers, the Japanese had almost 4,000 motorboats armed with high-explosive warheads to be used in nighttime attacks against troop carriers. Finally, the last line of maritime defense was the Japanese suicide frogmen called “Fukuryu.” These “crouching dragons” were divers armed with lunge mines, each capable of sinking landing crafts up to 950 tons. Thousands of these divers could stay submerged for up to 10 hours and were to thrust their explosive charges into the bottom of landing craft, in effect serving as human mines.
The principal goal of these special attack units of the air and sea was to shatter the invasion before the landing. The Japanese were convinced that by killing the combat troops aboard ships and sinking the attack transports and cargo vessels the Americans would back off or become so demoralized that they would accept a less than unconditional surrender and a more honorable face-saving end for the Japanese.
If the Allied forces were able to overcome all the Japanese efforts to forestall a landing and make it ashore to Japanese territory they would come face-to-face with an unimaginable array of defenses beyond those used on the Pacific islands, including poison gas and bacteriological warfare. Finally, there was the twenty-eight million strong civilian Japanese “National Volunteer Combat Force” many committed to fight to the death in the defense of their homeland.
It is no wonder that Bill was ready to proclaim the surrender of Japan as “the greatest day of my life.”