Washington, D.C. May 25, 1945

On this date in 1945 the U.S. Joint Chiefs of Staff, the primary national agency for the coor­di­na­tion and stra­te­gic direc­tion of U.S. armed forces, provided Presi­dent Harry S. Truman with a gene­ral out­line of a plan to invade Japan, the last Axis nation still fighting World War II. Three days later Gen. Douglas Mac­Arthur, Supreme Com­mander of Allied Forces in the South­west Pacific Area (SWPA), issued his stra­te­gic two-stage plan for an amphib­ious assault on Japan, code­named Oper­a­tion Down­fall. The first stage, Oper­a­tion Olym­pic, would be the inva­sion of Japan’s southern­most Home Island, Kyushu (Kyūshū), and the second stage, Oper­a­tion Coro­net, the invas­ion of Hon­shu (Honshū), Japan’s main island to the north of Kyushu. Ten­ta­tive dates for Kyushu’s inva­sion—November 1, 1945; Honshu’s—March 1, 1946.

After U.S. forces had secured the Philippines (for the most part) and seized Oki­nawa in June 1945, the Japa­nese cor­rectly deduced that the next Amer­i­can landings—these staged from Oki­nawa—would target Kyushu’s south­ern beaches (see map below). Aug­mented by men and equip­ment dis­patched from the Euro­pean to the Pacific thea­ter, the U.S. and its allies could be expected to use Kyushu as a spring­board for assaulting neigh­boring Honshu on which the Japa­nese capital, Tokyo, was located.

Approved by the Imperial High Command in March 1945, the Japa­nese scripted a secret plan to defeat the Allied assault on their home­land. Ketsu-Go was designed to engage the enemy’s inva­sion fleet as far from the Home Islands as pos­si­ble using special attack air­craft (kami­kaze), human-guided bombs, jet- and rocket-powered aerial bombs, and thou­sands of small sui­cide boats, midget sub­marines, and human tor­pe­does. Should the invaders manage to reach land­fall, the script called for their anni­hi­la­tion on Kyushu’s beaches. Japan’s mili­tarists, having been forced to sur­render much of their terri­torial gains of the past few years, realized their coun­try could not win the expan­sionist war they had started in the 1930s and ’40s. But by blunting, or best case turn back, the looming Amer­i­can assault on their home­land they hoped their nation could evade the ene­mies’ long-standing insis­tence on an uncon­di­tional sur­render in exchange for a negotiated peace.

Given Japan’s late-war military weaknesses, that was doubtful. How­ever, on paper Ketsu-Go appeared a reason­able defen­sive plan. (Iron­i­cally, only after Japan’s uncon­di­tional sur­ren­der on Septem­ber 2, 1945, in Tokyo Bay did Gen. Walter Krueger’s Sixth U.S. Army G-2 (intel­li­gence) offi­cers learn of Ketsu-Go when they inter­ro­gated men of Japan’s Second General Army.) Troops of the Second Gene­ral Army shoul­dered respon­si­bil­ity for defending the southern­most Home Island. Of the 14 divi­sions defending Kyushu when hostil­i­ties ended, two were divi­sions with­drawn from Chi­nese Man­chu­ria that lacked com­bat exper­ience. One divi­sion was trans­fer­red from Hok­kaido in the north, and an army head­quarters group moved from For­mosa (today’s Taiwan) to Kyushu. Seven divi­sions were cobbled together from recent recruits and recalled reser­vists. U.S. G-2 addi­tion­ally esti­mated that 140,000 recently mobi­lized civil­ian volun­teers stood guard in South­ern Kyushu and over 400,000 were deployed in the north. Tragi­cally for the defenders, num­bers mat­tered little because half of Kyushu’s 917,000 defenders lacked rifles and bay­o­nets, and mortars had replaced field artillery.

Still, Kyushu defenders played their assigned roles, ready or not. For­tu­nately for both com­bat­ant nations—Japan and the U.S.—hos­til­i­ties ceased on August 17, 1945, hours after Emperor Hiro­hito (post­humously referred to as Emperor Shōwa) broad­cast his capit­u­la­tion speech to the world. Kyushu was spared an Amer­i­can inva­sion though not Amer­i­can wrath. On August 9 Naga­saki, the large indus­trial city of 195,000 peo­ple in Kyushu’s north, was laid to nuclear waste. Dead (39,000) and in­jured (25,000), mostly civil­ians as aw­ful as that was, never approached the Sixth U.S. Army’s chilling esti­mate of 394,859 U.S. casual­ties had Oper­a­tion Olympic lasted 120 days.

Defending the Japanese Homeland Against the Planned U.S. Invasion, 1945–1946

Map of Kyushu, 1945

Above: Operation Olympic was to have been launched on Novem­ber 1, 1945, from an Allied naval armada that would have been the largest ever assembled, sur­passing the Over­lord (D-Day) inva­sion of Normandy, France, in June 1944. It was to have included 42 air­craft car­riers, 24 battle­ships, and 400 destroyers and destroyer escorts, and hun­dreds of troop trans­ports. Four­teen U.S. divi­sions and one “divi­sion-equi­va­lent” (two regi­mental com­bat teams) were sched­uled to take part in the ini­tial landings, three more divi­sions than Over­lord had. Tac­ti­cal air support for Olym­pic (renamed Majes­tic when that code­name appeared com­pro­mised) was to have been the respon­si­bil­ity of three U.S. Army Air Forces (the U.S. 5th, 7th, and 13th AAF), which were to win and main­tain air supe­ri­or­ity over 35 landing beaches named after auto­mobile brands at three points in the south­ern third of Kyushu, the southern­most of Japan’s four Home Islands. The points were Miya­zaki, Ari­ake, and Kushi­kino iden­ti­fied on the map by arrow­heads and the words “X” DAY. U.S. planners esti­mated that their three corps (l-r V, XI, and I), one corps assigned to each landing point, would out­num­ber the Japa­nese by approx­i­mately 3 to 1. The con­quest of South­ern Kyushu was to offer a staging ground and a valu­able air­base for Oper­a­tion Coro­net and the climac­tic Battle for Tokyo ten­ta­tively set to kick off on March 1, 1946.

Operation Ketsu-Go: Volunteer fighting corps in Tokorozawa, JapanKetsu-Go: Student militia at Kujukurihama, Chiba prefecture, 1945

Left: Female students receive training in gun hand­ling as mem­bers of a volun­teer fighting corps, or Kokumin Giyū Sentōtai, in Tokoro­zawa, now con­sidered a suburb of Tokyo. Governors of pre­fec­tures (states) could con­script all male civil­ians between the ages of 15 and 60 years, and un­married females between 17 and 40. Com­manders were appointed from retired mili­tary per­son­nel and civil­ians with wea­pons experi­ence. The Kokumin Giyū Sentōtai was in­tended as the main reserve, along with a “second defense line,” for Japa­nese forces to sus­tain a war of attri­tion against in­vading forces. After the Allied in­va­sion, these forces were intended to form resis­tance or guer­rilla war­fare cells in cities, towns, and moun­tains. At this stage of the war, most mili­tia mem­bers were armed with swords, sickles, knives, fire hooks, and even bam­boo spears due to the lack of modern weaponry and ammunition.

Right: Student militia at Kujukuri­hama, Chiba, a pre­fec­ture situ­ated east of Tokyo across Tokyo Bay. Some 28 mil­lion men and women were con­sidered “com­bat capable” by the end of June 1945; yet only about 2 mil­lion were recruited when the war ended, and most of these never exper­i­enced com­bat owing to Japan’s sur­render before the Allied invasion of the Japanese home islands could proceed.

Operation Ketsu-Go: Housewives with bamboo spearsOperation Ketsu-Go: Buddhist monks with rifles bayonets

Left: In this photo an officer of the Japanese Army instructs a group of housewives in the use of bamboo spears. Everyone was enlisted in the defense of the Japanese homeland.

Right: Rifles slung over their shoulders and bayonets lashed to their belts, Buddhist monks march in step under the watchful eye of a Japanese soldier. This drill took place on the grounds of their Buddhist temple.

Newsreel Documenting Japan’s Unconditional Surrender on Board the USS Missouri, September 2, 1945