Monday, December 1st, 1941
The final meeting of the Imperial Privy Council is held in Japan.
Prime Minister Hideki Tojo argues the case for war at any cost.
Some government advisers warn that Japan's economy cannot match America's, and point
out there are no plans in case of air raids on Tokyo, a mostly wooden city.
Privy Council President Yochimichi Hara replys: "The United States is acting in a conceited, stubborn, and disrespectful manner".
At the end Tojo concludes the meeting with saying that the Japanese
Empire stands at the threshold of glory or collapse, and promises that
a "united nation will go on to victory".
Alea iacta est! There will be a war. The ministers sign the documents
declaring war, and give them to Emperor Hirohito, who signs them a few
hours later, telling his aides that he does not feel that a
constitutional monarch can overturn his ministers on such a momentous decision.
In the meantime, in Washington D.C., Ambassador Admiral Kichisaboru
Nomura and Japanese special emissary Saboru Kurusu continue to talk
peace with US Foreign Secretary Cordell Hull.
The British put Malaya on full alert. The Admiralty in London suggests Phillips to
take his fleet, soon after her arrival in Singapore, on a short cruise
in the east waters of Singapore. The Admiralty is most probably afraid
of any unexpected air raids, similar to one that occured to the Italian fleet in Taranto 1940.
Foreign Minister Togo cabled Japanese Ambassador Nomura in Washington to continue negotiations "to prevent the U.S. from becoming unduly suspicious".
The Japanese Combined Fleet (Admiral Isoruku Yamamoto) was radioed this Imperial Naval Order: "Japan, under the necessity of her
self-preservation and self-defense, has reached a position to declare war on the United States of America, United Kingdom and the Netherlands.
The Supreme Commander of the Combined Fleet will start the war with an attack on the enemy fleet in the Hawaii Islands area and
destroy it with the 1st Air Fleet".
The Japanese Consul in Honolulu reported that ship manoeuvres were held
approximately 500 nautical miles southeast of Honolulu, with the battleships leaving Tuesday and returning Friday or leaving Friday and
returning Saturday of the following week. It was noted that the fleet had never sailed westward or headed for the "Kaiui" straits northward;
the sea west of the Hawaiian Islands was not suitable for ocean manoeuvres.
The estimate of distance was based on the fact that fuel was plentiful, long-distance high speed possible, and the guns could not be
heard at Honolulu.
Tuesday, December 2nd, 1941
Commander of the Combined Imperial Fleet Admiral Isoruku Yamamoto signaled the
Nagumo's Attack Fleet, through the Imperial Japanese Navy's main radio towers at Hario, on Kyushu Island, the secret message saying
"Climb Mount Niitaka" ["Niitaka Yama Nabore"], and gave date of attack.
[Mount Niitaka was the highest mountain of the Japanese Empire at that time - 13,113 feet. It is located on Formosa Island]
Tokyo directed the Japanese Consul at Honolulu to wire day-by-day reports
concerning observation balloons above Pearl Harbor, or any indication that they would be sent up.
American planes spotted 12 Japanese submarines off the French Indochina coast,
heading south, most probably toward Singapore, where on this day both British battleships arrived.
The intelligence reports noted that there is not a single Japanese merchant vessel on the whole Pacific, Atlantic or Indian Oceans,
but on the other hand they counted 21 large transport ships at an anchorage north of Saigon.
They also spotted approximately 180 planes on the airfields in the south of French Indochina.
Nearly half of them are being heavy bombers.
Japanese Foreign Minister Togo sends message to all Japanese consulates and
embassies in the United States to destroy all codes and other secret documents.
Wednesday, December 3rd, 1941
The Admiralty suggests Phillips dispatch both battleships from Singapore,
and to ask Admiral Hart, the commander of US Asiatic Fleet, if he could send his eight
destroyers, currently in the waters of the Dutch East Indies, to Singapore to reinforce the British fleet there.
Phillips replies that he will try to make an arrangement with Admiral Hart, and that he intends to send HMS Repulse on a short visit
to Darwin, Australia. He again asks the Admiralty if they intend to send him in Singapore the old battleships
HMS Revenge, HMS Royal Sovereign, HMS Resolution and HMS Ramillies.
Kita, the Japanese Consul-General in Honolulu (Hawaii Islands) sends a radiogram to Tokyo reporting the American warships at anchor in
Pearl Harbor, which include the battleships USS Oklahoma and USS Nevada, and the carrier USS Enterprise.
This information is immediately radioed to Vice-Admiral Chuichi Nagumo's Fleet, who has just reached a
point 1,300 miles northwest of Hawaii, and are now headed southeast, towards its target - Pearl Harbor.
In his office aboard the IJN battleship Nagato, Admiral Isoruku Yamamoto
writes a letter to one of his friend. He says: "If we attack America, it will not be necessary for us to seize California.
In order for us to make peace, we would have to march into the White House.
I wonder if those who would blindly lead us to war have thought about that!"
Thursday, December 4th, 1941
Admiral Sir Tom Phillips flies to Manila, Philippines, to meet with
General MacArthur and Admiral Hart in order to make an arrangement for Allied co-operation in Southeast Asia.
In the South China Sea, three divisions of Japanese troops are at sea, sailing to invade Malaya and Siam.
In Tokyo, the Japanese Foreign Ministry goes over the final note to the Americans, the one that will declare war.
They agree to deliver it at 1 p.m., Washington time, half an hour before the attack.
It will not include a simple declaration of war, but simply say that "in
view of the attitude of the American Government it must be concluded
that it is impossible to reach an agreement through further negotiations".
In the early morning, at a US Navy shortwave monitoring station in
Cheltenham, Maryland, a half-hour drive southeast of Washington, DC, a
27-year-old senior radio operator Ralph
Briggs was just coming on duty. He expected an ordinary morning, as he
tuned his receiver to the station and began transcribing what he heard.
At 8 a.m. he received the message he had been waiting for. It seemed to
be nothing more than a regional weather forecast, the kind that the
stations he monitored transmitted every day
during their news broadcasts in the morning. But Briggs knew what the
three words meant. The three words were casually spoken during the
regular news and weather feature from Radio Tokyo, Japan. The words
were "East Wind, Rain".
This sentence was one of three possible "execute" messages which
Japanese diplomats around
the world had been alerted to begin listening for on November 19th.
They were told to monitor the regular news and weather broadcasts from
Tokyo, just as they always did, but to pay especially careful attention
to the phraseology employed to describe the weather. If they heard the
words "East Wind, Rain," it means war with the United States. Briggs
knew this and he immediately teletyped the message to Washington.
Barely few miles away from Cheltenham, in Washington, DC, at the
Japanese Embassy, Chief Petty Officer Keniji Ogemoto also was listening
to the weather report. When he heard those fateful words, he
immediately rushed into the office of the naval attaché, Captain Yuzuru
Sanematsu, and shouted "The winds blew".
Captain Sanematsu ran with Ogemoto back into the radio room just in
time to hear the Radio Tokyo announcer repeat the weather forecast - "Higashi no kaze ame" - "East Wind, Rain".
Immediately the workers at the embassy began destroying their
cryptographic equipment and codebooks, while others took the secret
documents from their files, piled them in huge heaps in the garden, and
promptly burned them. The Japanese diplomats knew that their embassies
and consulates in the United States and its territories would soon be
seized, and they themselves would soon be interned as enemy aliens
pending their exchange for American diplomats in Japan. Therefore, all
their code-making and code-breaking hardware and software, and all
their secret papers, had to be destroyed as soon as possible.
Lieutenant General Hein Ter Poorten, the commander of the Dutch East Indies Army (KNIL) sent all the details
of the Winds Execute Message to Colonel Weijerman, the Dutch military attaché in Washington to pass on to the highest US military authorities.
The Dutch naval intelligence service in the Dutch East Indies had succeeded in intercepting and decrypting the Japanese naval message at
their intercept station Kamer 14 on Java Island.
Friday, December 5th, 1941
HMS Repulse, escorted by HMAS Vampire and HMS Tenedos,
sails from Singapore toward Darwin, Australia.
With this gesture Phillips granted the request of the Admiralty of
retreating the big ships from Singapore Harbour. He also hoped to
persuade the Australians to send their light cruiser HMAS Hobart
in the Eastern Fleet. He agrees with Hart that Singapore Harbour will
become in the case of the war their main starting point for an
offensive against Japan.
Japanese government assures the United States that her troop and ship movements in French Indochina are only precautionary.
In the morning, Task Force 12 (Rear-Admiral John H. Newton) with USS Lexington (CV-2) and escort ships leaves Pearl Harbor for Midway Island.
The aircraft carrier is transporting Marine Scout-Bomber Squadron VMSB-231 (18 Vought SB2U-3 Vindicator light bombers under the command of
Major Clarence J. Chappell) to Midway Island.
In the meantime, Task Force 8 (Vice-Admiral William F. Halsey, Jr.) with USS Enterprise (CV-6) and escort ships is approaching Wake Island.
Their mission is to unload Marine Fighter Squadron VMF-211 (12 Grumman F4F-3 Wildcats under the command of Major Paul A. Putnam) on the island.
USS Saratoga lies at a dockyard in San Diego for repairs.
The USS heavy cruiser Indianapolis and five destroyers leave for Johnston Island to test the performance of the Higgins landing boat on coral reefs.
All Japanese international shipping had returned to home port.
Saturday, December 6th, 1941
Hart and Phillips continue with their talks in Manila, Philippines. Hart agrees
to send four US destroyers from Balikpapan (Borneo) to Singapore, only
if Phillips also calls there three British destroyers from Hong Kong.
During the talks, a young American naval officer enters a room with an
important message. One Australian reconnaissance plane from Malaya
discovers that the Japanese convoy had left the anchorage at Saigon,
French Indochina. The plane commander, Flying Officer Ramshaw, reports
that at first only three ships sailed out, and shortly afterwards they
were followed by at least 25 new transport ships, escorted by a
battleship, five cruisers and seven destroyers [Ramshaw had mistaken
the heavy cruiser for a battleship]. By his opinion the ships were
intended for Thailand, which was at that time still neutral, or for
Malaya. This was no doubt a clear sign that the war is close. Admirals
reacted immediately. Four American destroyers in Balikpapan receive
orders to sail out, while Rear-Admiral Palliser (Phillip's C-in-C)
receive an instruction by Phillips to order HMS Repulse
to return back to Singapore. More messages about the Japanese convoy
follows. The British planes received orders to go on patrol missions,
but in the meantime the weather changed on worse, so they couldn't
perform any further recon flights.
In the afternoon, Japan sends the first segments of a 14-part message to its embassy in Washington, ordering them to
present their final demands to the United States at 1 p.m. Washington
time, tomorrow. The message is intercepted and decoded by the US Navy's
Cryptographic Department (Lt.Cdr. Alvin Kramer). He shows the message
to President Franklin D. Roosevelt, who reads the document, and says: "This means war".
He then immediately sends a personal message to Japan's Emperor
Hirohito, begging him to start negotiations afresh.
The message reached Tokyo after a long delay, caused by Japanese State
Telegraph Agency. US Ambassador Robert C. Grew passes it on to the
Foreign Ministry and asks for an immediate audience with the Emperor.
Prime Minister Hideki Tojo, denies the American request.
North of Hawaii, the attacking Japanese striking force increases speed
to 25 knots and quickly approaches to its destination point.
On his flagship, the aircraft carrier Akagi, Vice-Admiral Chuichi Nagumo sends a message to his fleet: "The fate of the Empire rests on this enterprise. Every man must devote himself totally to the task at hand".
At 21:00 hours the fleet reaches the 158th meridian, 490 sea miles north
of Hawaii Islands. They have met no ships during the twelve day
journey. Heavy winds had torn the flags into pieces and pushed more
than ten sailors into the rough sea. Everything else goes according to plans.
The last intelligence report before Pearl Harbor attack is transmitted by Mr. Nagao Kita and intercepted.
The Japanese Consul reported that a number of battleships and one submarine tender had entered port on the evening of December 5.
Nine battleships, three light cruisers, three submarine tenders, and 17 destroyers were at anchor, and four light cruisers and two destroyers
were lying at the docks.
The heavy cruisers and aircraft carriers had left Honolulu. It appeared that no air reconnaissance was being conducted by the fleet air arm.