The declining performance of the IJN and IJA air arms in the final year of the war convinced senior Japanese commanders that Tokko tactics were their last hope in the final defense of Japan. Consequently, kamikazes figured prominently in the plan for the final battle, Operation Ketsu-Go.
By the summer of 1945, there were few illusions about the ability of the IJA and IJN to prevent US amphibious landings on the Japanese coast. The strategic objective, therefore, was to inflict such severe losses on the American invaders that the United States would be willing to conduct political negotiations to bring about an end of the war, short of unconditional surrender. A conference at 6th Air Army headquarters in July 1945 concluded that Tokko missions could make a decisive contribution to repulsing the American naval landings, and would sink a third to a half of the invasion force. These estimations were in part based on grossly exaggerated assessments of the casualties already caused by the Tokko attacks. Japanese assessments were a mixture of poor information compounded by wishful thinking and propaganda efforts to justify the sacrifice of so many pilots. The erroneous predictions also diverted Japanese attention away from the technical lessons of the Okinawa campaign, in which most Tokko aircraft had a very low probability of sinking a warship even if they hit it. The ordnance carried on the aircraft, typically 550lb (250kg) bombs, were too small to guarantee the sinking even of small warships like destroyers, and were less effective against larger warships such as cruisers or battleships. The army suspected this to be the case, which was its reason for trying to convert bombers into Tokko aircraft with large warheads. Shortcomings in Tokko aircraft would only be exacerbated by the growing reliance on smaller planes for Tokko missions, such as trainers, that could not carry a powerful payload.
A common scene at many Japanese airbases in the weeks after the war was the removal of propellers from any aircraft that might be used for unauthorized kamikaze missions after the ceasefire. This is Atsugi airbase outside Tokyo, displaying a variety of IJN aircraft including Ginga and Suisei bombers. A final Tokko mission of the war was flown by Adm Matome Ugaki in a D4Y4 of the 701st Air Group from Oita airbase on August 15 after the Emperor’s surrender announcement. (NARA)
IJN commanders hoped to stop the US invasion fleet by the sheer volume of Tokko attacks. By the summer of 1944, the IJN had about 4,300 trainer aircraft in Japan that would be converted to the Tokko role. This figure included not only dedicated primary trainers and advanced trainers, but also obsolete fighters such as the Zero, which were now being used in the trainer role. In addition, 700 dive-bombers, torpedo-bombers, medium bombers, and other attack aircraft would be allotted to the Tokko force. The most modern fighters such as the Raiden (“Jack”) and Shiden (“George”) were initially withheld from the Tokko force on the presumption that escorts would be needed; likewise reconnaissance aircraft were also exempted. Eventually, however, all aircraft would be expended in Tokko attacks.
The army air brigades had a smaller force in Japan for the Ketsu-Go plan than the navy. Conversion of obsolete aircraft types, especially the Ki-43 Type 1 fighters, began in late 1944 and about 800 were ready by April 1945. By the end of the war, the army had only about 800 operational fighters and bombers and about 2,100 dedicated kamikaze aircraft in Japan and the neighboring air sectors. These were split between the 1st Air Army in the Tokyo area (600 kamikaze aircraft), 6th Air Army headquartered at Fukuoka (1,000), and the 5th Air Army headquartered at Seoul in Korea (500). Since the objective was to sink 500 American transport ships, plans were made to increase the inventory of Tokko aircraft by producing at least 2,000 new dedicated Tokko models such as the navy’s rocket-powered Ohka flying bomb (see below), and the army’s more conventional Tsuragi.
A July 1945 conference estimated that about 60 percent of the available navy force would actually be operational at the time of the American landings and that of the 2,400 taking part about one in six, or 400 aircraft, would score hits. The army argued more optimistically that one in three of its aircraft would score hits, since the targets would be in the crowded transport areas, not against a dispersed fleet with heavy antiaircraft protection as had been the case in the Philippines and Okinawa battles.
Although Tokko aircraft were the primary form of kamikaze weapon for Ketsu-Go, the navy also had a broad array of Tokko naval craft and submarines that will be detailed later in this book.