midway
us navy crypto
The breaking of Japanese Naval codes gave the Americans first hand knowledge of Japanese intentions as far as targets and times of attack which gave the US Navy time to counter Japanese tactics and strategy .
US Navy deciphered the Japanese attack plan by breaking the Japanese codes used for communicating with Japanese naval commanders. This allowed the U.S. to direct its carriers to sit back behind Midway island and launch air attacks on the large Japanese force.
The US in some ways laid a trap. They had broken much of the Imperial Japanese Naval Code, and sent an uncoded message indicating that Midway was short of fresh water. The Japanese picked up the message and relayed it back. The US fortified the island and sent a fleet of carriers, including some that the Japanese thought had already been sunk. Naval Intelligence confirmed that an Invasion Fleet was headed there and the US Navy was determined to defend the Island. It attacked the covering fleet and the Invasion Fleet could no longer proceed without air support. It sailed home.
The Japaneses naval code was broken by the allies, and imminent attack plans by the Japanese was decoded by the allies.
midway
US Naval code-breakers. The US Naval intelligence (code-breakers section) had begun to crack the super-encrypted Japanese Naval Code Kaigun Ango Sho D (known by US code-breakers as AN-1 and later called JN-25). Simplistically, this was a complex 'code within a code'. The Japanese coded-messages were transmitted by radio and then heard by US military (and Allied) listening posts throughout the Pacific. These messages were sent to a central collection office within US Naval intelligence to be decoded if possible. The more messages collected, the better the chance of finding patterns that enabled decoding of small bits of messages. Because of the US Doolittle Raid of 18 April 1942, Japanese radio traffic using the JN-25 codes dramatically increased. This assisted the US code-breakers to determine that some sort of Japanese offensive was planned for the eastern part of New Guinea & the Solomon Islands. This information was used by Admiral Nimitz to position two US aircraft carriers in the area. The US intelligence information was verified by the subsequent Battle of Coral Sea from 4-8 May 1942. This validated the earlier decoding and helped the Code breakers project that the next Japanese strike would be aimed at Midway based on the latest intercepts & partial decoding. The Japanese final decision to invade & seize Midway happened on 5 May 1942. Japanese instructions went out by radio in code thereafter. Starting 14 May 1942, the US code-breakers were getting the first hints of the Japanese Midway operation. By the next week US Admiral Nimitz was fairly certain that the Japanese would attack Midway the first week in June.
oliver perry
Adm. Perry
Based on an act of Congress, foreign naval officers were allowed to enroll and or be trained at the US Naval Academy. Six Japanese naval officers, cited for distinguished service by Japan were trained at the Academy. Two of them actually enrolled and were graduated. They were Admiral Uriu, and Lieutenant Commanders Niri and Tamura.
Oliver Perry was an 1853 naval officer who, persuaded the Japanese to trade with the U.S.
1941
The US naval base at Pearl Harbour was attacked by the Japanese. The USA declared war on the Japanese.
December 7, 1941
The same as US Naval bases in California.
They intercepted a mesage from Japan to its naval fleet.