Tokyo, Japan · March 24, 1945

On this date in 1945 the Japanese Deputy Minis­ter of War, Lt. Gen. Kaneshiro Shiba­yama, in­formed the Japa­nese Diet (Parlia­ment) of the for­ma­tion of a mili­tia for the defense of the Home Islands. A home mili­tia was criti­cal to the nation’s sur­vi­val because 60 per­cent of the roughly 4.6 mil­lion Japa­nese com­bat troops were still stationed aboard.

The next month, on April 8, the oper­a­tional plan to defend the home­land, called Ketsu‑Go (“Deci­sive Oper­a­tion”), was issued. As a result of les­sons learned in the South Pacific, the in­tent of Ketsu‑Go was to in­flict enor­mous casual­ties on the in­vaders. In fact, this stra­tegy had been tested most recently on the island of Iwo Jima in Feb­ru­ary and March 1945, where one in three U.S. Marines had been killed or wounded. Japa­nese tena­city in com­bat would, it was believed, under­mine the Amer­i­can public’s will to con­tinue the fight for Japan’s un­con­di­tional sur­render; instead, the Amer­i­can public would insist on a peace more advan­ta­geous to Japan than other­wise if for no other rea­son than to push the past four years of slaughter and misery out of their minds and bring “the boys” home.

Pre­par­a­tions for Ketsu‑Go were to be con­ducted in three phases. The first phase, during which defen­sive pre­pa­ra­tions and com­bat unit organ­i­za­tion were com­pleted, con­tinued through July 1945. (Com­bat unit organ­i­za­tion involved acti­vating the First and Second General Armies, the latter army head­quartered in Hiro­shima, as well as an Air General Army, which had at its dis­posal close to 13,000 air­craft, almost all of which were con­verted into one-way suicide planes.) The second and third phases of this all-out joint defense effort were to have ended in Oct­ober, when Japa­nese mili­tary offi­cials fore­cast an American invasion of the Home Islands might begin.

The latter two phases were never com­pleted because the Amer­i­cans had their own plan for under­mining the enemy’s will to con­tinue fighting—all this with­out any further high-cost air, sea, and ground oper­a­tions en­visioned in Oper­a­tion Down­fall (see map and descrip­tion below) and with­out any direct or behind-the-scenes diplo­ma­tic nego­ti­a­tions that might end with less than uncon­ditional Japa­nese sur­render. The Amer­i­can plan was awe­some and drama­tic and cen­tered on using a new wea­pon, the atomic bomb, two of which blasted, seared, and ir­ra­di­ated tens of thou­sands of com­ba­tants and non­com­ba­tants alike residing in Hiro­shima and Naga­saki on August 6 and 9, respec­tively. The way America de­ci­sively ended the war against Japan remains one of the great controversies in U.S. and Japanese history.

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

Planned U.S. Invasion of Japan, 1945–1946

Above: This map outlines the Japa­nese and U.S. ground forces scheduled to take part in Oper­a­tion Down­fall, the battle for Japan. Two landings were planned: Oper­a­tion Olym­pic, on the south­ern is­land, Kyūshū, set to begin around Novem­ber 1, 1945, and Oper­a­tion Coro­net, on the main is­land, Honshū, set to begin the following spring. The War Depart­ment staff in Washing­ton esti­mated there would be 250,000–800,000 fatal­i­ties in an in­va­sion of Japan—of which 5,000 casual­ties would occur at sea from kami­kaze strikes, per the U.S. Navy—and 5 to 10 mil­lion Japa­nese fatal­i­ties. Amer­i­can casual­ties were esti­mated to range between 1.7 and 4 mil­lion. The key assump­tion was large-scale parti­ci­pa­tion by civil­ian mili­tias in the defense of the Home Islands if the battle shifted to inland guer­rilla war­fare. Oper­a­tion Down­fall was aban­doned when Japan for­mally sur­ren­dered on Septem­ber 2, 1945, after the U.S. dropped atomic bombs on Hiro­shima and Naga­saki the pre­vious month. The half-million Purple Hearts pro­duced in preparation for invading Japan were not needed.

Operation Ketsu-Go: Volunteer fighting corps in Tokorozawa, JapanOperation Ketsu-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.

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