Above all, and as the Americans also knew, while various Japanese experimented with peace feelers through third countries, the Japanese military moved forward resolutely with plans for a final, all-out battle to defend the home islands. The defence plan was called ‘Ketsu-go’, or ‘Decisive Operation’. Adopted by Imperial General Headquarters in March 1945, Ketsu-go correctly anticipated that the Americans planned to invade the southern island of Kyushu and the Kanto Plain surrounding Tokyo. Military coordinators of the plan decided, first, to allow the Americans a beachhead on Kyushu—there seemed little choice, given US firepower as exhibited elsewhere in the Pacific—then to concentrate forces and lacerate the enemy before they could regroup and move inland. Second, the Japanese would use tokko, suicide attacks by planes, human torpedoes, and other devices manned by those willing to give up their lives to protect the homeland. Finally, planners envisioned full-scale mobilization of the population to attack the Americans with homemade weapons— pitchforks, shovels, improvised explosives, and whatever else came to hand. Over two dozen divisions of Japanese troops would deploy to southern Kyushu, there to await the invader. Kamikaze would take to the sky. Local civilians would help build roads, unload trucks, and torment the invaders with guerrilla tactics. Assistance would come also in the form of Kyushu’s topography, jagged and forbidding; the beaches gave way to high bluffs that would be difficult for the Americans to negotiate. Japanese commanders reminded their troops that twice in the thirteenth century invading Mongol armies had been wrecked at Kyushu—the second time by a providential typhoon the Japanese had christened ‘Divine Wind’, or Kamikaze.12
The American plan for invading Japan was drawn up in later May 1945. Called ‘Downfall’, it envisioned an attack on Kyushu beginning on 1 November (‘Olympic’), then an assault on the Kanto Plain (‘Coronet’) starting on 1 March 1946. The American planners, principally the Joint Chiefs of Staff and theater commander MacArthur, underestimated the number of divisions the Japanese intended to shift to southern Kyushu. But they knew the attack would be sharply contested. US intelligence that summer detected strenuous efforts by the Japanese to build artillery emplacements and to mine the land just beyond the beaches. In a move that was reminiscent of Okinawa, the Japanese were preparing cave defenses on the bluffs. The Americans worried that the limited number and poor quality of roads in the area would slow the invasion’s progress. And they took seriously statements duly recorded from Japanese government and media sources: the morale of the people was high, and—as on Okinawa— they would gladly fight to the death rather than surrender. The Japanese suspected that killing a large number of Americans in Kyushu’s interior would so alarm American public opinion that the US government would be forced to come to terms well short of its tiresome demand for unconditional surrender.13
What worried US planners most was their perception that the Japanese would do anything to defend their homeland, that the fighting during ‘Downfall’ would be more brutal on a massive scale than anything American troops had encountered thus far. They knew about Iwo and Okinawa, of course, and judged the merciless defense of those islands a logical extension of Japanese atrocities proved or rumored to have occurred previously elsewhere. The ‘Rape of Nanking’ in December 1937 was reported to have produced between 10,000 and 20,000 Chinese dead within its first few days—figures later revealed to have been too small by a factor of ten. Japanese soldiers raped Chinese and Korean women and forced them into prostitution on a scale as incomprehensible as it was appalling. Even before the Westerners had engaged in indiscriminate bombing of cities, the Japanese had rehearsed such a strategy against the Chinese war capital of Chungking, killing an estimated 5,000 civilians. Less well known, but even more heinous, was the use of poison gas, produced on the island of Okunoshima near Hiroshima, against the Chinese fighting in the mountains of Shanxi, and bacteriological agents, employed in Manchuria by the notorious Unit 731. The Japanese also launched over 9,000 ‘balloon bombs’ from Honshu into the Pacific jet stream in late 1944 and early 1945. Bearing antipersonnel and twin incendiary bombs, a handful of these odd weapons reached the northwestern United States and caused several casualties, and served further to remind Americans, if further reminder was needed, of Japanese ingenuity and nefariousness.14
Most of all, the Americans feared Japanese suicide attacks. In the fullness oftime, it is clear that these tactics were far more costly to the Japanese than to the Americans they targeted. Saburo Ienaga has estimated that ‘no more than 1 to 3 percent of the suicide pilots actually hit Allied warships’, and various other macabre devices—the oka (Cherry Blossom) ‘flying bomb’, the shinyo plywood motorboats with high explosives strapped to their bows, and the submarine kaiten human torpedo—proved even more unreliable, except as death traps for those driving them. Yet these statistics were not clear at the time. The tokkoo weapons terrified the Americans, and the threat of their lavish use in Ketsu-go deeply concerned them. Certainly there was commitment to these weapons on the part of their operators. Yokota Yutaka was a kaiten pilot whose missions were scrubbed because of malfunction or an absence of enemy targets. Ashamed of what he considered his own failure to fulfill his destiny, he was miserable (and disbelieving) when he heard the war had ended. His comrades had died, not him. ‘Tears sprang to my eyes,’ he remembered. ‘I cried bitterly. “I’ll never launch! The war is over...”’ During Ketsu-go Japanese command planned to target troop transports, slow, unarmed, and thus more vulnerable than warships. Shinyo would strike the anchored ships at night; kaiten would be deployed at close range; ‘Crouching Dragons’ (fukuryo), frogmen, submerged and holding mines at the ends of wooden poles, would ram US landing craft in the shallows off Kyushu. Five thousand kamikaze would strike during the first ten days of‘Olympic.’15
Such carnage as ‘Downfall’ would bring—10,000? 50,000? No one knew, and the guess hardly mattered—might be avoided altogether if atomic bombs were dropped on Japan, accompanied or not by Soviet entry into the war. ‘Think of the kids who won’t get killed,’ Truman wrote to his wife, Bess, on 18 July, having heard about the Trinity test and having got Stalin’s agreement to enter the war. On the same day, he wrote in his diary: ‘Believe Japs will fold up before Russia comes in. I am sure they will when Manhattan appears over their homeland.’ The uranium core of the Little Boy bomb was by then en route to Tinian. It arrived on the 26th. (Norman Ramsey, the chief scientist on the island, estimated the value of the uranium and accordingly signed a receipt for it, later wondering, with chagrin and amusement, how the government might dock his pay half a billion dollars if anything went wrong.)16