{"id":1286,"date":"2010-08-15T07:25:47","date_gmt":"2010-08-15T11:25:47","guid":{"rendered":"http:\/\/www.engineeringradio.us\/blog\/?p=3928"},"modified":"2023-07-09T16:39:18","modified_gmt":"2023-07-09T20:39:18","slug":"east-wind-rain","status":"publish","type":"post","link":"https:\/\/www.engineeringradio.us\/blog\/2010\/08\/east-wind-rain\/","title":{"rendered":"East wind rain"},"content":{"rendered":"\n
\"\"<\/a><\/figure>\n\n\n\n

Yesterday, August 14th, was the 65th anniversary of the end of World War II. \u00a0Prior to the start of the US involvement in WWII, the Army and Navy had been intercepting and decrypting radio messages between Japanese military units, consulates, embassies, and other overseas locations.<\/p>\n\n\n\n

Back in the day, most everything was sent via Morse code over HF radio circuits. \u00a0 It was the fastest way to send information from one point to the next. \u00a0These messages would be encrypted offline, either by hand or by a special typewriter. \u00a0The message text would then be altered into 5-number, seemingly random, groups. \u00a0On the other side, they would be deciphered using a key that matched the enciphering key. \u00a0 There were several different ciphers systems being used, some for diplomatic traffic, several others for military, merchant marine, etc.<\/p>\n\n\n\n

Since the messages were transmitted via radio, they were easy to intercept. \u00a0Everyone knew that the other side was listening. \u00a0The Japanese assumed that their codes were secure because a “Caucasian mind could not possibly unravel the intricacies of a Japanese code.” \u00a0An assumption the Navy cryptanalysts had different ideas about. \u00a0Through the 1930s and early 1940s they broke some of these codes, but not all of them.<\/p>\n\n\n\n

The Japanese diplomatic code was called “purple<\/a>” by the US cryptanalysts. \u00a0It relied on a machine called System 97 (by the Japanese) which used telephone stepper relays to generate an ever-changing stream of random code groups. \u00a0It was considered too secure to break. \u00a0William Friedman, a mathematician working for the Army, studied the purple messages and deduced that it was a machine-generated code. \u00a0He then went to work on duplicating the machine and after a year or so came up with a perfect replica of the Japanese System 97 machine in early 1941. \u00a0From that point on, almost all of Japan’s diplomatic message traffic was being read by the Army, Navy, and state departments. \u00a0This work was top secret and carried out at the war department in Washington. \u00a0Information gleaned would be sanitized and transmitted to major commands as needed for tactical intelligence.<\/p>\n\n\n\n

In early November 1941, the Japanese foreign office came up with the following code to be transmitted to the embassies in the event of the outbreak of war:<\/p>\n\n\n\n

HIGASHI NO KAZE AME (East wind rain) = Japan – US<\/p>\n\n\n\n

KITA NO KAZE KUMORI (North wind cloudy)= Japan – USSR<\/p>\n\n\n\n

NISHI NO KAZE HARE (West wind clear)= Japan – Britain<\/p>\n\n\n\n

It is believed that on either December 4th or 5th, East wind rain<\/em> message was received and decrypted. \u00a0This was testified to Congress in 1945 by the head of the Navy COMMINT section, however, no record of the decrypted message exists. \u00a0Instead, there is a blank page and a missing message number (JD-7001) in the Japanese diplomatic intercepts file.<\/p>\n\n\n\n

The fleet commander at Pearl Harbor<\/a> knew none of this, as the information was kept under close wraps by the Navy Department in Washington. \u00a0In early December 1941, almost everyone figured that war with Japan would happen very soon. \u00a0Most of the Washington set believed it would start in the Philippines, then a US territory. \u00a0No figured that the Japanese would steam 3,900 miles undetected and launch a sneak attack on the US military base in Hawaii. \u00a0The attacking planes homed in on the signal from KGMB (after-war reading of Cmd. Fuchida’s (IJN strike leader) diary indicates the actual station was KGMB on 590 KHz, and not KGU as their website claims), to help find Hawaii from carriers still 230 miles away. \u00a0The station had remained on the air overnight to assist a group of B-17 navigates from the west coast. \u00a0Unaware of the impending danger, the Hawaii military bases were enjoying a peaceful Sunday morning until 7:48 am, when the first bombs began to fall.<\/p>\n\n\n\n

Of course, had the Japanese pressed the attack and launched a third wave to take out the fuel storage and repair facilities, indeed, history might be different.  The Pacific Fleet would have had to retire to California, leaving Hawaii exposed and quite possibly invaded.<\/p>\n\n\n\n

Most people on the mainland first heard about the attack via radio. \u00a0At 2:22 pm Eastern time, the AP<\/a> issued a news bulletin and at 2:27 pm\u00a0CBS<\/a> broke into their Sunday afternoon programming to announce the attack. \u00a0The radio played an important part in WWII from start to finish.<\/p>\n","protected":false},"excerpt":{"rendered":"

Yesterday, August 14th, was the 65th anniversary of the end of World War II. \u00a0Prior to the start of the US involvement in WWII, the Army and Navy had been intercepting and decrypting radio messages between Japanese military units, consulates, embassies, and other overseas locations. Back in the day, most everything was sent via Morse … Continue reading East wind rain<\/span><\/a><\/p>\n","protected":false},"author":4,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[35],"tags":[140],"class_list":["post-1286","post","type-post","status-publish","format-standard","hentry","category-history","tag-wwii"],"_links":{"self":[{"href":"https:\/\/www.engineeringradio.us\/blog\/wp-json\/wp\/v2\/posts\/1286","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.engineeringradio.us\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.engineeringradio.us\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.engineeringradio.us\/blog\/wp-json\/wp\/v2\/users\/4"}],"replies":[{"embeddable":true,"href":"https:\/\/www.engineeringradio.us\/blog\/wp-json\/wp\/v2\/comments?post=1286"}],"version-history":[{"count":13,"href":"https:\/\/www.engineeringradio.us\/blog\/wp-json\/wp\/v2\/posts\/1286\/revisions"}],"predecessor-version":[{"id":12205,"href":"https:\/\/www.engineeringradio.us\/blog\/wp-json\/wp\/v2\/posts\/1286\/revisions\/12205"}],"wp:attachment":[{"href":"https:\/\/www.engineeringradio.us\/blog\/wp-json\/wp\/v2\/media?parent=1286"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.engineeringradio.us\/blog\/wp-json\/wp\/v2\/categories?post=1286"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.engineeringradio.us\/blog\/wp-json\/wp\/v2\/tags?post=1286"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}