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Japanese Naval Codes
The vulnerability of Japanese naval codes and ciphers was crucial to the conduct of World War II, and had an important influence on foreign relations between Japan and the west in the years leading up to the war as well. Every Japanese code was eventually broken, and the intelligence gathered made possible such operations as the victorious American ambush of the Japanese Navy at Midway in 1942 (by breaking code JN-25b) and the shooting down of Japanese admiral Isoroku Yamamoto a year later in Operation Vengeance. The Imperial Japanese Navy (IJN) used many codes and ciphers. All of these cryptosystems were known differently by different organizations; the names listed below are those given by Western cryptanalytic operations. Red code The Red Book code was an IJN code book system used in World War I and after. It was called "Red Book" because the American photographs made of it were bound in red covers.Greg Goebel"US Codebreakers In The Shadow Of War" 2018. It should not be confu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
World War II
World War II or the Second World War, often abbreviated as WWII or WW2, was a world war that lasted from 1939 to 1945. It involved the vast majority of the world's countries—including all of the great powers—forming two opposing military alliances: the Allies and the Axis powers. World War II was a total war that directly involved more than 100 million personnel from more than 30 countries. The major participants in the war threw their entire economic, industrial, and scientific capabilities behind the war effort, blurring the distinction between civilian and military resources. Aircraft played a major role in the conflict, enabling the strategic bombing of population centres and deploying the only two nuclear weapons ever used in war. World War II was by far the deadliest conflict in human history; it resulted in 70 to 85 million fatalities, mostly among civilians. Tens of millions died due to genocides (including the Holocaust), starvation, ma ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
OP-20-G
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 U.S. Navy's signals intelligence and cryptanalysis group during World War II. Its mission was to intercept, decrypt, and analyze naval communications from Japanese, German, and 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 "Blue" book fleet code. This was made possible by intercept and High Frequency Direction Finder (HFDF) sites in the Pacific, 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 Division of Naval Communications (DNC), as Op-20-G, on July 1, 1922. In January 1924, a 34-year-old U.S. Navy lieutenant named Laurance F. Safford ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nisshin Maru
The is the primary vessel of the Japanese whaling fleet and is the world's only whaler factory ship. It was the research base ship for the Institute of Cetacean Research for 2002 to 2007. It has a tonnage of and is the largest member and flagship of the five-ship whaling fleet, headed by leader Shigetoshi Nishiwaki. The ship is based in Japan in Shimonoseki harbor and is owned by Tokyo-based Kyodo Senpaku, which is a subsidiary of the Institute of Cetacean Research. History There have been several Japanese factory whaling ships named ''Nisshin Maru''. After the U.S. Navy's Pacific Fleet was attacked at Pearl Harbor on December 7, 1941, all Japanese factory ships soon began to serve in the war effort till sunk or till the end of World War II in 1945. *''Nisshin Maru'' (16,764 grt), commissioned in 1936, was a whaling factory ship built by Taiyo Gyogyo from a purchased blueprint of the Norwegian factory ship ''Sir James Clark Ross''. This ''Nisshin Maru'' was sunk by the sub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Factory Ship
A factory ship, also known as a fish processing vessel, is a large ocean-going vessel with extensive on-board facilities for processing and freezing caught fish or whales. Modern factory ships are automated and enlarged versions of the earlier whalers and their use for fishing has grown dramatically. Some factory ships are equipped to serve as a mother ship. Background Contemporary factory ships have their origins in the early whalers. These vessels sailed into remote waters and processed the whale oil on board, discarding the carcass. Later whalers converted the entire whale into usable products. The efficiency of these ships and the predation they carried out on whales contributed greatly to the animals' steep decline. Contemporary factory ships are automated and enlarged versions of these earlier whalers. Their use for fishing has grown dramatically. For a while, Russia, Japan and Korea operated huge fishing fleets centred on factory ships, though in recent times this use has ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Whale
Whales are a widely distributed and diverse group of fully aquatic placental marine mammals. As an informal and colloquial grouping, they correspond to large members of the infraorder Cetacea, i.e. all cetaceans apart from dolphins and porpoises. Dolphins and porpoises may be considered whales from a formal, cladistic perspective. Whales, dolphins and porpoises belong to the order Cetartiodactyla, which consists of even-toed ungulates. Their closest non-cetacean living relatives are the hippopotamuses, from which they and other cetaceans diverged about 54 million years ago. The two parvorders of whales, baleen whales (Mysticeti) and toothed whales (Odontoceti), are thought to have had their last common ancestor around 34 million years ago. Mysticetes include four extant (living) families: Balaenopteridae (the rorquals), Balaenidae (right whales), Cetotheriidae (the pygmy right whale), and Eschrichtiidae (the grey whale). Odontocetes include the Monodontidae (beluga ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Japanese Ship Naming Conventions
Japanese ship names follow different conventions from those typical in the West. Merchant ship names often contain the word ''maru'' at the end (meaning ''circle''), while warships are never named after people, but rather after objects such as mountains, islands, weather phenomena, or animals. Merchant ships The word is often attached to Japanese ship names. The first ship known to follow this practice was the ''Nippon Maru'', flagship of ''daimyō'' Toyotomi Hideyoshi's 16th century fleet. Several theories purport to explain this practice: *The most common is that ships were thought of as floating castles, and the word referred to the defensive "circles" or ''maru'' that protected the castle. *The suffix ''-maru'' is often applied to words representing something beloved, and sailors applied this suffix to their ships. *The term ''maru'' is used in divination and represents perfection or completeness, or the ship as "a small world of its own". *The myth of '' Hakudo Maru'', ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Known Plaintext Attack
The known-plaintext attack (KPA) is an attack model for cryptanalysis where the attacker has access to both the plaintext (called a crib), and its encrypted version (ciphertext). These can be used to reveal further secret information such as secret keys and code books. The term "crib" originated at Bletchley Park, the British World War II decryption operation, where it was defined as: History The usage "crib" was adapted from a slang term referring to cheating (e.g., "I cribbed my answer from your test paper"). A "crib" originally was a literal or interlinear translation of a foreign-language text—usually a Latin or Greek text—that students might be assigned to translate from the original language. The idea behind a crib is that cryptologists were looking at incomprehensible ciphertext, but if they had a clue about some word or phrase that might be expected to be in the ciphertext, they would have a "wedge," a test to break into it. If their otherwise random attacks on the ci ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
