Atomic bombings of Hiroshima and Nagasaki in the context of "Cold War"

Nagasaki (長崎, Nagasaki; Japanese pronunciation: [na.ɡaꜜ.sa.kʲi, na.ŋa-], lit. 'Long Cape'), officially Nagasaki City (長崎市, Nagasaki-shi; [na.ɡa.sa.kʲi̥ꜜ.ɕi, na.ɡa.saꜜ.kʲi̥.ɕi, na.ŋa-]), is the capital and the largest city of Nagasaki Prefecture on the island of Kyushu in Japan.

Founded by the Portuguese, the port of Nagasaki became the sole port used for trade with the Portuguese and Dutch during the 16th through 19th centuries. The Hidden Christian Sites in the Nagasaki Region have been recognized and included in the UNESCO World Heritage Sites list. Part of Nagasaki was home to a major Imperial Japanese Navy base during the First Sino-Japanese War and Russo-Japanese War. Near the end of World War II, the American atomic bombings of Hiroshima and Nagasaki made Nagasaki the second city in the world to experience a nuclear attack. The city was later rebuilt.

The surrender of the Empire of Japan in World War II was announced by Emperor Hirohito on 15 August and formally signed on 2 September 1945, ending the war. By the end of July 1945, the Imperial Japanese Navy (IJN) was incapable of conducting major operations and an Allied invasion of Japan was imminent. Together with the United Kingdom and China, the United States called for the unconditional surrender of Japan in the Potsdam Declaration on 26 July 1945—the alternative being "prompt and utter destruction". While publicly stating their intent to fight on to the bitter end, Japan's leaders (the Supreme Council for the Direction of the War, also known as the "Big Six") were privately making entreaties to the publicly neutral Soviet Union to mediate peace on terms more favorable to the Japanese. While maintaining a sufficient level of diplomatic engagement with the Japanese to give them the impression they might be willing to mediate, the Soviets were covertly preparing to attack Japanese forces in Manchuria and Korea (in addition to South Sakhalin and the Kuril Islands) in fulfillment of promises they had secretly made to the US and the UK at the Tehran and Yalta Conferences.

On 6 August 1945, at 8:15 am local time, the United States detonated an atomic bomb over the Japanese city of Hiroshima. Sixteen hours later, American president Harry S. Truman called again for Japan's surrender, warning them to "expect a rain of ruin from the air, the like of which has never been seen on this earth." Late on 8 August 1945, in accordance with the Yalta agreements, but in violation of the Soviet–Japanese Neutrality Pact, the Soviet Union declared war on Japan, and soon after midnight on 9 August 1945, the Soviet Union invaded the Japanese puppet state of Manchukuo. Hours later, the U.S. dropped a second atomic bomb on the Japanese city of Nagasaki.

The nuclear arms race was an arms race competition for supremacy in nuclear warfare between the United States, the Soviet Union, and their respective allies during the Cold War. During this same period, in addition to the American and Soviet nuclear stockpiles, other countries developed nuclear weapons, though no other country engaged in warhead production on nearly the same scale as the two superpowers.

The race began during World War II, dominated by the Western Allies' Manhattan Project and Soviet atomic spies. Following the atomic bombings of Hiroshima and Nagasaki, the Soviet Union accelerated its atomic bomb project, resulting in the RDS-1 test in 1949. Both sides then pursued an all-out effort, realizing deployable thermonuclear weapons by the mid-1950s. The arms race in nuclear testing culminated with the 1961 Tsar Bomba. Atmospheric testing was ended in the 1963 Partial Nuclear Test Ban Treaty. Subsequent work focused on the miniaturization of warheads at LLNL and VNIITF, and the neutron bomb.

The Boeing B-29 Superfortress is a retired American four-engined propeller-driven heavy bomber, designed by Boeing and flown primarily by the United States during World War II and the Korean War. Named in allusion to its predecessor, the Boeing B-17 Flying Fortress, the Superfortress was designed for high-altitude strategic bombing, but also excelled in low-altitude night incendiary bombing, and in dropping naval mines to blockade Japan. Silverplate B-29s dropped the atomic bombs on Hiroshima and Nagasaki, the only aircraft ever to drop nuclear weapons in combat.

One of the largest aircraft of World War II, the B-29 was designed with state-of-the-art technology, which included a pressurized cabin, dual-wheeled tricycle landing gear, and an analog computer-controlled fire-control system that allowed one gunner and a fire-control officer to direct four remote machine gun turrets. The $3 billion cost of design and production (equivalent to $52 billion in 2024), far exceeding the $1.9 billion cost of the Manhattan Project, made the B-29 program the most expensive of the war. The B-29 remained in service in various roles throughout the 1950s, being retired in the early 1960s after 3,970 had been built. A few were also used as flying television transmitters by the Stratovision company. The Royal Air Force flew the B-29 with the service name Washington from 1950 to 1954 when the jet-powered Canberra entered service.

A strategic bomber is a medium-to-long-range bomber aircraft designed to drop large amounts of air-to-ground weaponry onto a distant target for the purposes of debilitating the enemy's capacity to wage war. Unlike tactical bombers, penetrators, fighter-bombers, and attack aircraft, which are used in air interdiction operations to attack enemy combatants and military equipment, strategic bombers are designed to fly into enemy territory to destroy strategic targets (e.g., infrastructure, logistics, military installations, factories, etc.). In addition to strategic bombing, strategic bombers can be used for tactical missions. There are currently only three countries that operate strategic heavy bombers: the United States, Russia and China.

The modern strategic bomber role appeared after strategic bombing was widely employed, and atomic bombs were first used during World War II. Nuclear strike missions (i.e., delivering nuclear-armed missiles or bombs) can potentially be carried out by most modern fighter-bombers and strike fighters, even at intercontinental range, with the use of aerial refueling, so any nation possessing this combination of equipment and techniques theoretically has such capability. Primary delivery aircraft for a modern strategic bombing mission need not always necessarily be a heavy bomber type, and any modern aircraft capable of nuclear strikes at long range is equally able to carry out tactical missions with conventional weapons. An example is France's Mirage IV, a small strategic bomber replaced in service by the ASMP-equipped Mirage 2000N fighter-bomber and Rafale multirole fighter.

Silverplate was the code reference for the United States Army Air Forces' participation in the Manhattan Project during World War II. Originally the name for the aircraft modification project which enabled a B-29 Superfortress bomber to drop an atomic weapon, "Silverplate" eventually came to identify the training and operational aspects of the program as well. The original directive for the project had as its subject line "Silver Plated Project," but continued usage of the term shortened it to "Silverplate".

Testing began with scale models at the Naval Proving Ground in Dahlgren, Virginia, in August 1943. Modifications began on a prototype Silverplate B-29 known as the "Pullman" in November 1943, and it was used for bomb flight testing at Muroc Army Air Field in California commencing in March 1944. The testing resulted in further modifications to both the bombs and the aircraft.

The bombing of Tokyo (東京大空襲, Tōkyō daikūshū) was a series of air raids on Japan by the United States Army Air Forces (USAAF), primarily launched during the closing campaigns of the Pacific Theatre of World War II in 1944–1945, prior to the atomic bombings of Hiroshima and Nagasaki.

The strikes conducted by the USAAF on the night of 9–10 March 1945, codenamed Operation Meetinghouse, constitute the single most destructive aerial bombing raid in human history. Sixteen square miles (41 km; 10,000 acres) of central Tokyo was destroyed, leaving an estimated 100,000 civilians dead and over one million homeless.

A firestorm is a conflagration which attains such intensity that it creates and sustains its own wind system. It is most commonly a natural phenomenon, created during some of the largest bushfires and wildfires. Although the term has been used to describe certain large fires, the phenomenon's determining characteristic is a fire with its own storm-force winds from every point of the compass towards the storm's center, where the air is heated and then ascends.

The Black Saturday bushfires, the 2021 British Columbia wildfires, and the Great Peshtigo Fire are possible examples of forest fires with some portion of combustion due to a firestorm, as is the Great Hinckley Fire. Firestorms have also occurred in cities, usually due to targeted explosives, such as in the aerial firebombings of London, Hamburg, Dresden, and Tokyo, and the atomic bombing of Hiroshima.