Imperial Japanese Navy in the context of "Surrender of Japan"

Air warfare was a major component in all theaters of World War II and, together with anti-aircraft warfare, consumed a large fraction of the industrial output of the major powers. Germany and Japan depended on air forces that were closely integrated with land and naval forces; the Axis powers downplayed the advantage of fleets of strategic bombers and were late in appreciating the need to defend against Allied strategic bombing. By contrast, Britain and the United States took an approach that greatly emphasized strategic bombing and (to a lesser degree) tactical control of the battlefield by air as well as adequate air defenses. Both Britain and the U.S. built substantially larger strategic forces of large, long-range bombers. Simultaneously, they built tactical air forces that could win air superiority over the battlefields, thereby giving vital assistance to ground troops. The U.S. Navy and Royal Navy also built a powerful naval-air component based on aircraft carriers, as did the Imperial Japanese Navy; these played the central role in the war at sea.

The Empire of Japan, also known as the Japanese Empire or Imperial Japan, was the Japanese nation state that existed from the Meiji Restoration on January 3, 1868, until the Constitution of Japan took effect on May 3, 1947. From August 1910 to September 1945, it included the Japanese archipelago, the Kurils, Karafuto, Korea, and Taiwan. The South Seas Mandate and concessions such as the Kwantung Leased Territory were de jure not internal parts of the empire but dependent territories. In the closing stages of World War II, with Japan defeated alongside the rest of the Axis powers, the formalized surrender was issued on September 2, 1945, in compliance with the Potsdam Declaration of the Allies, and the empire's territory subsequently shrunk to cover only the Japanese archipelago resembling modern Japan.

Under the slogans of "Enrich the Country, Strengthen the Armed Forces" and "Promote Industry" which followed the Boshin War and the restoration of power to the emperor from the shogun, Japan underwent a period of large-scale industrialization and militarization, often regarded as the fastest modernization of any country to date. All of these aspects contributed to Japan's emergence as a great power following the First Sino-Japanese War, the Boxer Rebellion, the Russo-Japanese War, and World War I. Economic and political turmoil in the 1920s, including the Great Depression, led to the rise of militarism, nationalism, statism and authoritarianism, during which Japan joined the Axis alliance with Nazi Germany and Fascist Italy, conquering a large part of the Asia–Pacific; during this period, the Imperial Japanese Army (IJA) and the Imperial Japanese Navy (IJN) committed numerous atrocities and war crimes, including the Nanjing Massacre. There has been a debate over defining the political system of Japan as a dictatorship, which has been disputed due by the absence of a dictator, and over calling it fascist. The other suggested terms were para-fascism, militarism, corporatism, totalitarianism, and police state.

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.

Marines (or naval infantry) are military personnel generally trained to operate on both land and sea, with a particular focus on amphibious warfare. Historically, the main tasks undertaken by marines have included raiding ashore (often in support of naval objectives) and the boarding of vessels during ship-to-ship combat or capture of prize ships. Marines also assisted in maintaining security, discipline, and order aboard ships (reflecting the historically pressed-nature of the rest of the ship's company and the risk of mutiny). While maintaining many of their historical roles, in modern times, marines also engage in duties including rapid-response operations, humanitarian aid, disaster relief, special operations roles, and counter-terrorism operations. In most nations, marines are an integral part of that state's navy, such as the United Kingdom's Royal Marines or Russia's Naval Infantry; in some countries their marine forces can instead be part of the land army, such as the French Troupes de marine, or, more uncommonly, a nation’s marine forces may be an independent military branch such as the United States Marine Corps or the Ukrainian Marine Corps.

The exact term "marine" is not found in many languages other than English. In French-speaking countries, two terms which could be translated as "marine", but do not translate exactly: troupes de marine (marine troops) and fusiliers-marins (marine riflemen) and fuzileiros navais in Portuguese (lit. 'Naval fusiliers'). The word marine means "navy" in many European languages such as Dutch, French, German, Italian and Norwegian. “Naval infantry” may also refer to sailors forming both temporary and permanent infantry units, such as the British WWI-era 63rd (Royal Naval) Division (an infantry division made-up of Royal Navy sailors and Royal Marines on a semi-permanent basis) or the Imperial Japanese Naval Landing Forces (ad-hoc formations of Imperial Japanese Navy sailors temporarily pressed into service as infantry).

The Imperial Japanese Armed Forces (IJAF, full Japanese: 帝国陸海軍, romanized: Teikoku riku-kaigun or Nippon-gun (日本軍) for short, meaning "Japanese Forces") were the unified forces of the Empire of Japan. Formed during the Meiji Restoration in 1868, they were disbanded in 1945, shortly after Japan's defeat to the Allies of World War II; the revised Constitution of Japan, drafted during the Allied occupation of Japan, replaced the IJAF with the present-day Japan Self-Defense Forces.

The Imperial Japanese Army and the Imperial Japanese Navy functioned as the IJAF's primary service branches, with the country's aerial power being split between the Army Air Service under the former and the Navy Air Service under the latter.

The Imperial Japanese Navy land forces (大日本帝國海軍陸戦隊, Dai-Nippon Teikoku Kaigun Rikusentai) were a variety of land-based units of the Imperial Japanese Navy (IJN) organized for offensive operations, the defense of Japanese naval and shore-based facilities, military policing tasks, construction and engineering, training, and shore-based anti-aircraft roles; both overseas, and in the Japanese home islands. Units ranged from dedicated military police formations, to ad-hoc groups of naval personnel pressed into service as naval infantry, to professional marines, among others. The land forces were most active during the interwar period and World War II, with IJN land forces complementing, supporting, and in some cases, operating in-place of Imperial Japanese Army units. Upon Imperial Japan’s surrender, IJN land forces were disbanded alongside the IJN proper in 1945.

Before and during World War II, the Empire of Japan committed numerous war crimes and crimes against humanity across various Asian–Pacific nations, notably during the Second Sino-Japanese War and the Pacific War. These incidents have been referred to as "the Asian Holocaust" and "Japan's Holocaust", and also as the "Rape of Asia". The crimes occurred during the early part of the Shōwa era.

The Imperial Japanese Army (IJA) and the Imperial Japanese Navy (IJN) were responsible for war crimes leading to millions of deaths, ranging from sexual slavery and massacres to human experimentation, torture, starvation, and forced labor. Evidence of these crimes, including oral testimonies and written records such as diaries and war journals, has been provided by Japanese veterans.