It consisted of more than 120,000 people working on 37 different sites across 19 states in the US and in Canada, at a cost of more than $2 billion. The invasion was not intended to conquer the entire island, just the southernmost third of it, as indicated by the dashed line on the map labeled "general limit of northern advance". [4], At the time, the development of the atomic bomb was a very closely guarded secret (not even then-Vice President Harry Truman knew of its existence until he became President), known only to a few top officials outside the Manhattan Project (and to the Soviet espionage apparatus, which had managed to infiltrate agents into, or recruit agents from within the program, despite the tight security around it), and the initial planning for the invasion of Japan did not take its existence into consideration. [19] Coronet would have been even larger than Olympic, with up to 45 U.S. divisions assigned for both the initial landing and follow-up. The Japanese staged a furious defence, which included kamikaze suicide attacks (c. 1900 sorties) against the invasion fleet. In China, Operation Ichigo started in April 1944. ", "That approximately three (3) hostile divisions will be disposed in Southern Kyushu and an additional three (3) in Northern Kyushu at initiation of the Olympic operation. Nimitz planned a pre-invasion feint, sending a fleet to the invasion beaches a couple of weeks before the real invasion, to lure out the Japanese on their one-way flights, who would then find ships bristling with anti-aircraft guns instead of the valuable, vulnerable transports. "[51] They were expected to serve as a "second defense line" during the Allied invasion, and to conduct guerrilla warfare in urban areas and mountains. "[72] An air burst 1,8002,000ft (550610m) above the ground had been chosen for the (Hiroshima) bomb to achieve maximum blast effects, and to minimize residual radiation on the ground, as it was hoped that American troops would soon occupy the city. This article appears in: . The Cold War Notes. Allied command was divided into regions: by 1945, for example, Chester Nimitz was the Allied C-in-C Pacific Ocean Areas, while Douglas MacArthur was Supreme Allied Commander, South West Pacific Area, and Admiral Louis Mountbatten was the Supreme Allied Commander, South East Asia Command. This raid burned 15.8 square miles of Tokyo, killing almost 100,000 Japanese. A devastating typhoon in October 1945 would have delayed Allied invasion preparations, while bad weather in the winter and spring of 1946 would have hampered operations and logistics. 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. The Army began experimenting with compounds to destroy crops in April 1944, and within one year had narrowed over 1,000 agents to nine promising ones containing phenoxyacetic acids. Alternatively, search more than 1 million objects from About 400,000 Japanese died as a result of these raids plus the dropping of the atomic bombs. However, the German invasion of the Soviet Union in June 1941 forced the suspension of this plan: the Soviets had to divert most of their resources to fighting the Germans and their allies, primarily on land, throughout most of the war, leaving their navy relatively poorly equipped. Japans surrender in Manchuria. Before 1944, the Japanese continued to plan for an aggressive attack against the Chinese and Soviets to advance their territorial goals in the Far East. Pushing back against U.S. attempts to limit Japan's aggressive expansion, Japan launched a . At the Yalta Conference in February 1945 the Allies agreed to the Soviet conditions which included restoration of her special rights in Manchuria after their defeat during the Russo-Japanese war of 1904-5. In preparation for the invasion, an air campaign against Japanese airfields and transportation arteries had commenced before the Japanese surrender. [70], On Marshall's orders, Major General John E. Hull looked into the tactical use of nuclear weapons for the invasion of the Japanese home islands, even after the dropping of two strategic atomic bombs on Japan (Marshall did not think that the Japanese would capitulate immediately). One compound designated LN-8 performed best in tests and went into mass production. President Harry Truman received news of itwhilst at the Potsdam Conference. Even when rounded down to a conservative 200,000, this figure implied a total of nearly 500,000 all-causes losses, of whom perhaps 50,000 might return to duty after light to moderate care. [3], Responsibility for the planning of Operation Downfall fell to American commanders Fleet Admiral Chester Nimitz, General of the Army Douglas MacArthur and the Joint Chiefs of StaffFleet Admirals Ernest King and William D. Leahy, and Generals of the Army George Marshall and Hap Arnold (the latter being the commander of the U.S. Army Air Forces). [3] [71], Ken Nichols, the District Engineer of the Manhattan Engineer District, wrote that at the beginning of August 1945, "[p]lanning for the invasion of the main Japanese home islands had reached its final stages, and if the landings actually took place, we might supply about fifteen atomic bombs to support the troops. Ultimately, the Army's viewpoint prevailed. [11] The Army, on the other hand, argued that such a strategy could "prolong the war indefinitely" and expend lives needlessly, and therefore that an invasion was necessary. They and their soldiers had endured three years of harsh captivity. Ending the war quickly would prevent Russian participation in the fighting and expansion into parts of Asia. On 9 August, the Soviet Union repudiated the Soviet-Japanese Neutrality Pact and launched a full-scale invasion of Manchuria in the Soviet-Japanese War of 1945. At 11 pm Trans-Baikal time on 8 August 1945, Soviet foreign minister Vyacheslav Molotov informed Japanese ambassador . Through April, May, and June, Allied intelligence followed the buildup of Japanese ground forces, including five divisions added to Kysh, with great interest, but also some complacency, still projecting that in November the total for Kysh would be about 350,000 servicemen. When these figures were questioned by General Marshall, MacArthur submitted a revised estimate of 105,000, in part by deducting wounded men able to return to duty. Osprey Publishing. Japan and the Soviet Union formally made peace four years later, when they signed the Soviet-Japanese Joint Declaration of 1956. War with Japan. The Soviets had arrived to train on the first of 149 vessels the U.S. Navy was transferring to the Soviet . Stalin had agreed to enter the war against Japan at the Teheran Conference in 1943. Plan 2 has the Japanese invading the West Coast of America via Pearl Harbor and then California. [103] 149,425 Okinawans were killed, committed suicide, or went missing, which was one-half of the estimated pre-war local population of 300,000. [104] Nearly 500,000 Purple Heart medals (awarded for combat casualties) were manufactured in anticipation of the casualties resulting from the invasion of Japan; the number exceeded that of all American military casualties of the 65 years following the end of World War II, including the Korean and Vietnam Wars. [citation needed], The main defense against Japanese air attacks would have come from the massive fighter forces being assembled in the Ryukyu Islands. These ranged from 0.42 dead and missing and 2.16 total casualties per 1000 men per day under the "European Experience" to 1.95 dead and missing and 7.45 total casualties per 1000 men per day under the "Pacific Experience. The Americans considered Okinawa a dress rehearsal for the invasion of the Japanese home islands, for which the United States was finalizing a two-stage plan. Invasion Planning, and the A-Bomb Decision", https://en.wikipedia.org/w/index.php?title=Operation_Downfall&oldid=1152535827, "That operations in this area will be opposed not only by the available organized military forces of the Empire, but also by a fanatically hostile population. According to this analysis, the real reason for Japan's surrender was the Soviet invasion of Japanese-controlled Manchuria on 9 August 1945, mere hours before the Nagasaki bombing. [105] There were so many left that combat units in Iraq and Afghanistan could keep Purple Hearts on hand for immediate award to soldiers wounded in the field.[105]. President Truman had four options: 1) continue conventional bombing of Japanese cities; 2) invade Japan; 3) demonstrate the bomb on an unpopulated island; or, 4 . [6], The primary considerations that the planners had to deal with were time and casualtieshow they could force Japan's surrender as quickly as possible with as few Allied casualties as possible. If not checked, this threatened "to grow to [the] point where we attack on a ratio of one (1) to one (1) which is not the recipe for victory. The race to produce the first atomic weapon before Germanywas headed by the Manhattan project. 12 The Eastern Front: The German War against the Soviet Union. The Twentieth Air Force was to have continued its role as the main Allied strategic bomber force used against the Japanese home islands, operating from airfields in the Mariana Islands. For the failed Mongol invasion attempts, see, "Soviet invasion of Japan" redirects here. As set out in prior parts of the series, communications intelligence revealed the massive Japanese build up on southern Kyushu, the planned target for an initial invasion of Japan in November 1945 (Operation OLYMPIC.) The Soviet Union declared war on Japan and invaded Japanese-held Manchuria on the night of August 8. Giangreco argues that the alternative, a land invasion of . If the US casualty rate during the invasion of Japan had been only 5% as high per unit area as it was at Okinawa, the US would still have lost 297,000 soldiers (killed or missing). "[61], By the time of surrender, the Japanese had over 735,000 military personnel either in position or in various stages of deployment on Kyushu alone. ", Henry L. Stimson, "The Decision to use the Atomic Bomb" p. 11, "Okinawa: The Final Great Battle of World War II", "The Final Months of the War with Japan. General Arthur MacArthur and the army planners urged an early assault on Kyushu followed by an invasion of the main island of Honshu. 13 . This page was last edited on 30 April 2023, at 20:51. The G-7 consists of the United States, Japan, Britain, France, Germany, Italy and Canada. Instead, at the Quebec conference, the Combined Chiefs of Staff agreed that Japan should be forced to surrender not more than one year after Germany's surrender. Set to begin in November 1945, Operation Olympic was intended to capture the southern third of the southernmost main Japanese island, Kysh, with the recently captured island of Okinawa to be used as a staging area. The Americans lost 36 ships. They hoped that at least 15 to 20% (or even up to a half) of the US transport ships would be destroyed before disembarkation. In early 1945, Miyazaki was virtually undefended, while Ariake, with its good nearby harbor, was heavily defended. There were two unsuccessful Japanese counterattacks which ultimately weakened the capability of the defending forces to resist the American onslaught. A study done for Stimson's staff by William Shockley estimated that invading Japan would cost 1.74 million American casualties, including 400,000800,000 fatalities, and five to ten million Japanese fatalities. More than seventy years after the end of World War II, the decision to drop the atomic bombs on Hiroshima and Nagasaki remains controversial. The ensuing Operation Downfall envisaged two main assaults Operation Olympic on Kyushu, planned for early November and Operation Coronet, the invasion of Honshu in March 1946. [21] Later, a follow-up force of up to 20 additional U.S. divisions and up to 5 or more British Commonwealth divisions would have landed as reinforcements. For Soviet invasion of Manchuria under Japanese rule, see, Allied re-evaluation of Operation Olympic. The B-29 Superfortresses were then withdrawn from China to bomb Japan from the Marianas. 6 part 1. The invasion of the second largest Japanese island of Hokkaido was originally planned by the Soviets to be part of the territory taken, when finally in August 7 the Soviets declared war on Japan. According to Edward J. Drea, the strategic use of chemical weapons on a massive scale was not seriously studied or proposed by any senior American leader; rather, they debated the tactical use of chemical weapons against pockets of Japanese resistance. Stavros Atlamazoglou. The offensive was finally halted in December. The entire island of Okinawa is 464sqmi (1,200km2). Invasion of Japan, 1945-46 by D.M. The Soviet invasion of the Kuril Islands (18 August 1 September 1945) took place after Japan's capitulation on 15 August. Russia launched a full-scale invasion of Ukraine in February 2022. In the Allied party were Generals Percival and Wainwright who had surrendered to the Japanese in 1942 at Singapore and in the Philippines respectively. Olympic was also to include a deception plan, known as Operation Pastel. Their surrender was caused by the dropping of two nuclear bombs by the United States on Aug 6 and Aug 9, on the cities of . Reinforcements would have been available from those countries, as well as other parts of the Commonwealth. [82], According to Thomas B. Allen and Norman Polmar, the Soviets had carefully drawn up detailed plans for the Far East invasions, except that the landing for Hokkaido "existed in detail" only in Stalin's mind and that it was "unlikely that Stalin had interests in taking Manchuria and even taking on Hokkaido. . The planned operation was canceled when Japan surrendered following the atomic bombings of Hiroshima and Nagasaki, the Soviet declaration of war, and the invasion of Manchuria. "[99] From D-Day to V-E Day, the Western Allies alone suffered some 766,294 casualties. The casualty rate on Okinawa was 35%;with 767,000 men scheduled to participate in taking Kyushu, it was estimated that there would be 268,000 casualties. The defending forces of 77,000 troops (and 20,000 Okinawan militia) largely hid in the caves during the bombardment which withstood all but a direct hit to the entrance, with the resulting raising of Japanese morale. Pastel was designed to convince the Japanese that the Joint Chiefs had rejected the notion of a direct invasion and instead were going to attempt to encircle and bombard Japan. 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.[37]. The Soviets invaded Japan-held Manchuria on Aug. 9. Operation August Storm, the massive 1945 Soviet invasion of Manchuria, was Japan's death blow, and brought an end to World War II.
