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Naval Communications Annex
OP-20-G or "Office of Chief Of Naval Operations (OPNAV), 20th Division of the Office of Naval Communications, G Section / Communications Security", was the United States Navy, U.S. Navy's signals intelligence and cryptanalysis group during World War II. Its mission was to intercept, decrypt, and analyze naval communications from Imperial Japanese Navy, Japanese, Germany, German, and Italy, Italian navies. In addition OP-20-G also copied diplomatic messages of many foreign governments. The majority of the section's effort was directed towards Japan and included breaking the early Japanese Japanese naval codes, "Blue" book fleet code. This was made possible by intercept and High-frequency direction finding, High Frequency Direction Finder (HFDF) sites in the Pacific Ocean, Pacific, Atlantic Ocean, Atlantic, and continental U.S., as well as a Japanese telegraphic code school for radio operators in Washington, D.C. History The Code and Signal Section was formally made a part of the Di ...
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Signals Intelligence
Signals intelligence (SIGINT) is intelligence-gathering by interception of ''signals'', whether communications between people (communications intelligence—abbreviated to COMINT) or from electronic signals not directly used in communication (electronic intelligence—abbreviated to ELINT). Signals intelligence is a subset of intelligence collection management. As classified and sensitive information is usually encrypted, signals intelligence in turn involves the use of cryptanalysis to decipher the messages. Traffic analysis—the study of who is signaling whom and in what quantity—is also used to integrate information again. History Origins Electronic interceptions appeared as early as 1900, during the Boer War of 1899–1902. The British Royal Navy had installed wireless sets produced by Marconi on board their ships in the late 1890s, and the British Army used some limited wireless signalling. The Boers captured some wireless sets and used them to make vital transmis ...
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Atlantic Ocean
The Atlantic Ocean is the second-largest of the world's five oceans, with an area of about . It covers approximately 20% of Earth's surface and about 29% of its water surface area. It is known to separate the " Old World" of Africa, Europe and Asia from the "New World" of the Americas in the European perception of the World. The Atlantic Ocean occupies an elongated, S-shaped basin extending longitudinally between Europe and Africa to the east, and North and South America to the west. As one component of the interconnected World Ocean, it is connected in the north to the Arctic Ocean, to the Pacific Ocean in the southwest, the Indian Ocean in the southeast, and the Southern Ocean in the south (other definitions describe the Atlantic as extending southward to Antarctica). The Atlantic Ocean is divided in two parts, by the Equatorial Counter Current, with the North(ern) Atlantic Ocean and the South(ern) Atlantic Ocean split at about 8°N. Scientific explorations of the A ...
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New York City
New York, often called New York City or NYC, is the List of United States cities by population, most populous city in the United States. With a 2020 population of 8,804,190 distributed over , New York City is also the List of United States cities by population density, most densely populated major city in the United States, and is more than twice as populous as second-place Los Angeles. New York City lies at the southern tip of New York (state), New York State, and constitutes the geographical and demographic center of both the Northeast megalopolis and the New York metropolitan area, the largest metropolitan area in the world by urban area, urban landmass. With over 20.1 million people in its metropolitan statistical area and 23.5 million in its combined statistical area as of 2020, New York is one of the world's most populous Megacity, megacities, and over 58 million people live within of the city. New York City is a global city, global Culture of New ...
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Pacific
The Pacific Ocean is the largest and deepest of Earth's five oceanic divisions. It extends from the Arctic Ocean in the north to the Southern Ocean (or, depending on definition, to Antarctica) in the south, and is bounded by the continents of Asia and Oceania in the west and the Americas in the east. At in area (as defined with a southern Antarctic border), this largest division of the World Ocean—and, in turn, the hydrosphere—covers about 46% of Earth's water surface and about 32% of its total surface area, larger than Earth's entire land area combined .Pacific Ocean
. '' Britannica Concise.'' 2008: Encyclopædia Britannica, Inc.
The centers of both the

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United States Marine Corps
The United States Marine Corps (USMC), also referred to as the United States Marines, is the maritime land force service branch of the United States Armed Forces responsible for conducting expeditionary and amphibious operations through combined arms, implementing its own infantry, artillery, aerial, and special operations forces. The U.S. Marine Corps is one of the eight uniformed services of the United States. The Marine Corps has been part of the U.S. Department of the Navy since 30 June 1834 with its sister service, the United States Navy. The USMC operates installations on land and aboard sea-going amphibious warfare ships around the world. Additionally, several of the Marines' tactical aviation squadrons, primarily Marine Fighter Attack squadrons, are also embedded in Navy carrier air wings and operate from the aircraft carriers. The history of the Marine Corps began when two battalions of Continental Marines were formed on 10 November 1775 in Philadelphia as ...
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US Navy
The United States Navy (USN) is the maritime service branch of the United States Armed Forces and one of the eight uniformed services of the United States. It is the largest and most powerful navy in the world, with the estimated tonnage of its active battle fleet alone exceeding the next 13 navies combined, including 11 allies or partner nations of the United States as of 2015. It has the highest combined battle fleet tonnage (4,635,628 tonnes as of 2019) and the world's largest aircraft carrier fleet, with eleven in service, two new carriers under construction, and five other carriers planned. With 336,978 personnel on active duty and 101,583 in the Ready Reserve, the United States Navy is the third largest of the United States military service branches in terms of personnel. It has 290 deployable combat vessels and more than 2,623 operational aircraft . The United States Navy traces its origins to the Continental Navy, which was established during the American Revolut ...
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Kana
The term may refer to a number of syllabaries used to write Japanese phonological units, morae. Such syllabaries include (1) the original kana, or , which were Chinese characters (kanji) used phonetically to transcribe Japanese, the most prominent magana system being ; the two descendants of man'yōgana, (2) , and (3) . There are also , which are historical variants of the now-standard hiragana. In current usage, 'kana' can simply mean ''hiragana'' and ''katakana''. Katakana, with a few additions, are also used to write Ainu. A number of systems exist to write the Ryūkyūan languages, in particular Okinawan, in hiragana. Taiwanese kana were used in Taiwanese Hokkien as glosses (ruby text or ''furigana'') for Chinese characters in Taiwan when it was under Japanese rule. Each kana character (syllabogram) corresponds to one sound or whole syllable in the Japanese language, unlike kanji regular script, which corresponds to a meaning (logogram). Apart from the five vowels, ...
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Wabun Code
is a form of Morse code used to send Japanese language in kana characters. Unlike International Morse Code, which represents letters of the Latin script, in Wabun each symbol represents a Japanese kana. For this reason, Wabun code is also sometimes called Kana code. When Wabun code is intermixed with International Morse code, the prosign () is used to announce the beginning of Wabun, and the prosign () is used to announce the return to International Code. Chart Kana in Iroha The is a Japanese poem. Originally the poem was attributed to the founder of the Shingon Esoteric sect of Buddhism in Japan, Kūkai, but more modern research has found the date of composition to be later in the Heian period (794–1179). Th ... order. Expanded chart References External links CW Wabun
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Diplomacy
Diplomacy comprises spoken or written communication by representatives of states (such as leaders and diplomats) intended to influence events in the international system.Ronald Peter Barston, ''Modern diplomacy'', Pearson Education, 2006, p. 1 Diplomacy is the main instrument of foreign policy which represents the broader goals and strategies that guide a state's interactions with the rest of the world. International treaties, agreements, alliances, and other manifestations of international relations are usually the result of diplomatic negotiations and processes. Diplomats may also help to shape a state by advising government officials. Modern diplomatic methods, practices, and principles originated largely from 17th-century European custom. Beginning in the early 20th century, diplomacy became professionalized; the 1961 Vienna Convention on Diplomatic Relations, ratified by most of the world's sovereign states, provides a framework for diplomatic procedures, methods, and co ...
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Officer (armed Forces)
An officer is a person who holds a position of authority as a member of an armed force or uniformed service. Broadly speaking, "officer" means a commissioned officer, a non-commissioned officer, or a warrant officer. However, absent contextual qualification, the term typically refers only to a force's ''commissioned officers'', the more senior members who derive their authority from a commission from the head of state. Numbers The proportion of officers varies greatly. Commissioned officers typically make up between an eighth and a fifth of modern armed forces personnel. In 2013, officers were the senior 17% of the British armed forces, and the senior 13.7% of the French armed forces. In 2012, officers made up about 18% of the German armed forces, and about 17.2% of the United States armed forces. Historically, however, armed forces have generally had much lower proportions of officers. During the First World War, fewer than 5% of British soldiers were officers (partly ...
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Japanese Language
is spoken natively by about 128 million people, primarily by Japanese people and primarily in Japan, the only country where it is the national language. Japanese belongs to the Japonic or Japanese- Ryukyuan language family. There have been many attempts to group the Japonic languages with other families such as the Ainu, Austroasiatic, Koreanic, and the now-discredited Altaic, but none of these proposals has gained widespread acceptance. Little is known of the language's prehistory, or when it first appeared in Japan. Chinese documents from the 3rd century AD recorded a few Japanese words, but substantial Old Japanese texts did not appear until the 8th century. From the Heian period (794–1185), there was a massive influx of Sino-Japanese vocabulary into the language, affecting the phonology of Early Middle Japanese. Late Middle Japanese (1185–1600) saw extensive grammatical changes and the first appearance of European loanwords. The basis of the standard dialect moved f ...
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Radio
Radio is the technology of signaling and communicating using radio waves. Radio waves are electromagnetic waves of frequency between 30 hertz (Hz) and 300 gigahertz (GHz). They are generated by an electronic device called a transmitter connected to an antenna which radiates the waves, and received by another antenna connected to a radio receiver. Radio is very widely used in modern technology, in radio communication, radar, radio navigation, remote control, remote sensing, and other applications. In radio communication, used in radio and television broadcasting, cell phones, two-way radios, wireless networking, and satellite communication, among numerous other uses, radio waves are used to carry information across space from a transmitter to a receiver, by modulating the radio signal (impressing an information signal on the radio wave by varying some aspect of the wave) in the transmitter. In radar, used to locate and track objects like aircraft, ships, spacecraf ...
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