Editing Operation Downfall (section)

==Operation Ketsugō==
[[File:Operation Downfall - Estimated Troops 01.jpg|thumb|250px|American estimates of Japanese troop strength on Kyūshū as of July 9, 1945]]
[[File:Operation Downfall - Estimated Troops 02.jpg|thumb|250px|American estimates of Japanese troop strength on Kyūshū as of August 2, 1945]]
{{further|:ja:決号作戦}}

Meanwhile, the Japanese had their own plans. Initially, they were concerned about an invasion during the summer of 1945. However, the [[Battle of Okinawa]] went on for so long that they concluded the Allies would not be able to launch another operation before the [[1945 Pacific typhoon season|typhoon season]], during which the weather would be too risky for amphibious operations. Japanese intelligence predicted fairly closely where the invasion would take place: southern Kyūshū at Miyazaki, Ariake Bay and/or the [[Satsuma Peninsula]].{{sfn|Skates|p=102}}

While Japan no longer had a realistic prospect of winning the war, Japan's leaders believed they could make the cost of invading and occupying the Home Islands too high for the Allies to accept, which would lead to some sort of [[armistice]] rather than total defeat. The Japanese plan for defeating the invasion was called {{nihongo|Operation Ketsugō [[w:ja:決号作戦|(ja)]]|決号作戦|ketsugō sakusen}} ("Operation: Decisive" or "Final Battle"). The Japanese planned to commit the entire population of Japan to resisting the invasion, and from June 1945 onward, a propaganda campaign calling for "The Glorious Death of One Hundred Million" commenced.{{sfn|Murray|Millet|2000|p=520}} The main message of "The Glorious Death of One Hundred Million" campaign was that it was "glorious to die for the holy emperor of Japan, and every Japanese man, woman, and child should die for the Emperor when the Allies arrived".{{sfn|Murray|Millet|2000|p=520}}

Although it was not realistic that the entire Japanese population would be killed off, both American and Japanese officers at the time predicted a Japanese death toll in the millions.{{sfn|Murray|Millet|2000|p=520}} From the Battle of Saipan onward, Japanese propaganda intensified the glory of patriotic death and depicted the Americans as merciless "white devils."{{sfn|Dower|1986|pp=246–47}} During the Battle of Okinawa, Japanese officers had ordered civilians unable to fight to commit suicide rather than fall into American hands, and all available evidence suggests the same orders would have been given in the home islands.{{sfn|Dower|1986|p=299}} The Japanese were secretly [[Matsushiro Underground Imperial Headquarters|constructing an underground headquarters]] in Matsushiro, Nagano Prefecture, to shelter the Emperor and the Imperial General Staff during an invasion. In planning for Operation Ketsugo, IGHQ overestimated the strength of the invading forces: while the Allied invasion plan called for fewer than 70 divisions, the Japanese expected up to 90.{{sfn|Giangreco|2009|p=62}}

===''Kamikaze''===
Admiral [[Matome Ugaki]] was recalled to Japan in February 1945 and given command of the [[Fifth Air Fleet]] on Kyūshū. The Fifth Air Fleet was assigned the task of ''[[kamikaze]]'' attacks against ships involved in the invasion of Okinawa, [[Operation Ten-Go]], and began training pilots and assembling aircraft for the defense of Kyūshū, the first invasion target.

The Japanese defense relied heavily on ''kamikaze'' planes. In addition to fighters and bombers, they reassigned almost all of their trainers for the mission. More than 10,000 aircraft were ready for use in July (with more by October), as well as hundreds of newly built [[Shin'yō-class suicide motorboat|small suicide boat]]s to attack Allied ships offshore.

Up to 2,000 ''kamikaze'' planes launched attacks during the Battle of Okinawa, achieving approximately one hit per nine attacks. At Kyūshū, because of the more favorable circumstances (such as terrain that would reduce the Allies' radar advantage, and the impressment of wood and fabric airframe training aircraft into the ''kamikaze'' role which would have been difficult for Allied radar systems of the time to detect and track), they hoped to raise that to one for six by overwhelming the US defenses with large numbers of ''kamikaze'' attacks within a period of hours. The Japanese estimated that the planes would sink more than 400 ships; since they were training the pilots to target transports rather than carriers and destroyers, the casualties would be disproportionately greater than at Okinawa. One staff study estimated that the ''kamikazes'' could destroy a third to half of the invasion force before landing.{{sfn|Frank|pp=184–85}}

Admiral King, Commander-in-Chief of the U.S. Navy, was so concerned about losses from ''kamikaze'' attacks that he and other senior naval officers argued for canceling Operation Downfall and for instead continuing the fire-bombing campaign against Japanese cities and the blockade of food and supplies until the Japanese surrendered.{{sfn|Murray|Millet|2000|pp=520–21}} However, General Marshall argued that forcing surrender that way might take several years, if ever.{{sfn|Murray|Millet|2000|p=521}} Accordingly, Marshall and United States Secretary of the Navy [[Frank Knox]] concluded the Americans would have to invade Japan to end the war, regardless of casualties.{{sfn|Murray|Millet|2000|p=521}}

===Naval forces===
Despite the shattering damage it had absorbed by this stage of the war, the [[Imperial Japanese Navy]], by then organized under the Navy General Command, was determined to inflict as much damage on the Allies as possible. Remaining major warships numbered four battleships (all damaged), five damaged aircraft carriers, two cruisers, 23 destroyers, and 46 submarines.<ref name="Japanese Monograph No. 85 pp. 16">[http://www.ibiblio.org/hyperwar/Japan/Monos/pdfs/JM-85/JM-85.pdf Japanese Monograph No. 85], p. 16. Retrieved August 23, 2015.</ref> However, the IJN lacked enough fuel for further sorties by its capital ships and planned instead to use its anti-aircraft firepower to defend naval installations while docked in port.<ref name="Japanese Monograph No. 85 pp. 16"/> Despite its inability to conduct large-scale fleet operations, the IJN still maintained a fleet of thousands of warplanes and possessed nearly 2 million personnel in the Home Islands, ensuring it a large role in the coming defensive operation.

In addition, Japan had about 100 [[Koryu class submarine|''Kōryū'']]-class [[midget submarine]]s, 300 smaller [[Kairyū-class submarine|''Kairyū'']]-class midget submarines, 120 ''[[Kaiten]]'' [[manned torpedo]]es,<ref name="Japanese Monograph No. 85 pp. 16"/> and 2,412 ''[[Shinyo (suicide boat)|Shin'yō]]'' suicide motorboats.{{sfn|Giangreco|2009|p=131}} Unlike the larger ships, these, together with the destroyers and fleet submarines, were expected to see extensive action defending the shores, with a view to destroying about 60 Allied transports.{{sfn|Giangreco|2009|p=257}}

The Navy trained a unit of [[frogman|frogmen]] to serve as suicide bombers, the [[Fukuryu]]. They were to be armed with contact-fuzed [[Naval mine|mines]], and to dive under landing craft and blow them up. An inventory of mines was anchored to the sea bottom off each potential invasion beach for their use by the suicide divers, with up to 10,000 mines planned. Some 1,200 suicide divers had been trained before the Japanese surrender.<ref>Zaloga, Steven (2011). Kamikaze: Japanese Special Attack Weapons 1944–45. Osprey Publishing. p. 43. {{ISBN|978-1849083539}}.</ref><ref>Barton, Charles A. (1983). "Underwater Guerrillas". Proceedings. United States Naval Institute. 109 (8): 46–47</ref>

===Ground forces===
The two defensive options against amphibious invasion are strong defense of the beaches and [[defense in depth]]. Early in the war (such as at [[Battle of Tarawa|Tarawa]]), the Japanese employed strong defenses on the beaches with little or no manpower in reserve, but this tactic proved vulnerable to pre-invasion [[Naval gunfire support|shore bombardment]]. Later at [[Battle of Peleliu|Peleliu]], [[Battle of Iwo Jima|Iwo Jima]], and Okinawa, they switched strategies and dug in their forces in the most defensible terrain.{{citation needed|date = July 2014}}

For the defense of Kyūshū, the Japanese took an intermediate posture, with the bulk of their defensive forces a few kilometers inland, back far enough to avoid complete exposure to naval bombardment, but close enough that the Americans could not establish a secure foothold before engaging them. The counteroffensive forces were still farther back, prepared to move against the largest landing.{{citation needed|date = July 2014}}

In March 1945, there was only one combat division in Kyūshū. Four veteran divisions were withdrawn from the [[Kwantung Army]] in [[Manchuria]] in March 1945 to strengthen the forces in Japan,{{sfn|Giangreco|2009|p=21}} and 45 new divisions were activated between February and May 1945. Most were immobile formations for coastal defense, but 16 were high quality mobile divisions.{{sfn|Giangreco|2009|pp=70–72}} By August, the formations, including three tank brigades, had a total of 900,000 men.{{sfn|Frank| p= 203}} Although the Japanese were able to muster new soldiers, equipping them was more difficult. By August, the Japanese Army had the equivalent of 65 divisions in the homeland but only enough equipment for 40 and ammunition for 30.{{sfn|Frank|p= 176}}

The Japanese did not formally decide to stake everything on the outcome of the Battle of Kyūshū, but they concentrated their assets to such a degree that there would be little left in reserve. By one estimate, the forces in Kyūshū had 40% of all the ammunition in the Home Islands.{{sfn|Frank|p= 177}}

In addition, the Japanese had organized the [[Volunteer Fighting Corps]], which included all healthy men aged 15 to 60 and women 17 to 40 for a total of 28 million people, for combat support and, later, combat jobs. Weapons, training and uniforms were generally lacking: many were armed with nothing better than antiquated firearms, [[molotov cocktail]]s, [[yumi|longbow]]s, swords, knives, bamboo or wooden spears, and even clubs and truncheons: they were expected to make do with what they had.{{sfn | Frank| pp =188–89}}{{Sfn | Bauer & Coox}} One mobilized high school girl, Yukiko Kasai, found herself issued an [[Scratch awl|awl]] and told, "Even killing one American soldier will do. ... You must aim for the [[abdomen]]."{{sfn|Frank|p= 189}} They were expected to serve as a "second defense line" during the Allied invasion, and to conduct [[guerrilla warfare]] in urban areas and mountains.

The Japanese command intended to organize its Army personnel according to the following plan:<ref>[http://www.k2x2.info/istorija/japonija_v_voine_1941_1945_gg/p10.php#metkadoc12 Hattori, "Japan at War: 1941–1945"] part 9 chapter 2. Retrieved April 6, 2018.</ref>

{| class="wikitable plainrowheaders"
|+ Mobilization plan
! scope="col" | Region
! scope="col" | Number mobilized
|-
| Kyushu
| 900,000
|-
| Kanto (Tokyo)
| 950,000
|-
| Korea
| 247,000
|-
| '''Total'''
| 3,150,000
|-
| colspan="2" | '''For the decisive battle'''
|-
|Kyushu
|990,000
|-
|Kanto
| 1,280,000
|-
|}