JAPANESE PREPARATIONS FOR THE ATTACK ON PEARL HARBOR
Admiral Yamamoto plans the Destruction of the United States Pacific Fleet
These aircraft are superb reproductions of the Nakajima Type 97 carrier torpedo bombers (Allied code-name "Kate") that attacked the United States Pacific Fleet at Pearl Harbor. They were used in the gripping and historically accurate 20th Century Fox film Tora, Tora, Tora! (1970).
In conformity with this traditional approach to naval warfare, the Japanese Naval General Staff intended to limit naval operations in support of Japan's military thrust into South-East Asia to offensive actions against local American, British and Dutch naval forces defending their country's colonial possessions in South-East Asia. To the conservative admirals of the Naval General Staff, a direct confrontation in the central Pacific Ocean between their navy and the United States Navy was unthinkable.
In early 1941, Vice Admiral Isoroku Yamamoto was appointed Commander-in-Chief of Japan's Combined Fleet, and he immediately took issue with the cautious policy of the Japanese Naval General Staff. Yamamoto did not believe that the United States Pacific Fleet would remain idle at Pearl Harbor while Japan attacked and seized America's Philippines, and British and Dutch colonial possessions in South-East Asia. He believed that Japan must cripple the United States Pacific Fleet at the same time as it launched its attacks on countries of South-East Asia.
With this firm conviction, Admiral Yamamoto began to consider a surprise carrier-launched air attack on the United States Pacific Fleet at its Pearl Harbor base timed to coincide with Japan's military aggression in South-East Asia. Yamamoto instructed Rear Admiral Takijiro Onishi, Chief of Staff of the 11th Air Fleet, to assess the feasibility of an attack on Pearl Harbor by carrier-launched aircraft. Onishi enlisted the assistance of Commander Minoru Genda, a brilliant staff officer and tactician serving with Japan's 1st Air Fleet. Genda studied the problem and came to the conclusion that an attack on Pearl Harbor could succeed if (a) the attack took the Americans completely by surprise, (b) the attack occurred early on a Sunday morning when American defence preparedness would be at a low level, (c) all six of Japan's best aircraft carriers were used, and (d) highly skilled aircrews were used in the attack. To ensure complete surprise, Genda's plan precluded alerting the Americans to their danger by a prior declaration of war.
Admiral Yamamoto's plan for a surprise peacetime attack on the United States Pacific Fleet at Hawaii would involve a strike force which included Japan's six largest and most powerful aircraft carriers. His task was made much easier by President Roosevelt's decision to relocate the United States Pacific Fleet from California to Hawaii. As Yamamoto saw it, the destruction of the American Pacific Fleet would give Japan time to seize the Philippines, Malaya, British Borneo, Burma and the Netherlands East Indies (now Indonesia), and gain access to the oil, minerals, rubber and other resources that Japan needed to sustain its aggressive war machine. He was hopeful that, with its Pacific Fleet destroyed or crippled, the Americans would be willing to accept a peace settlement that allowed Japan to keep its new conquests in South-East Asia.
The Japanese Naval General Staff initially rejected Admiral Yamamoto's plan for an attack on Pearl Harbor as being too great a gamble. They doubted that surprise could be achieved when the strike force would be at sea for two weeks before the attack. Japan had eleven aircraft carriers, and the admirals felt that Yamamoto's plan could put at risk their six best carriers. They also felt that diverting Japan's six most powerful aircraft carriers to Hawaii would leave the southern attacks on the Philippines and British Malaya dangerously unprotected. In the end, Yamamoto only overcame their opposition by threatening to resign.
Although the admirals of the Naval General Staff were reluctantly persuaded by Yamamoto to abandon the policy of defensive naval war in favour of attack, the years of night warfare training and the highly accurate, long range torpedoes associated with the defensive policy would give the Japanese Imperial Navy a significant edge over Allied navies in night actions during the Pacific War.
Training for the Pearl Harbor Attack
Early in 1941, despite the fact that the Chief of the Naval General Staff, Admiral Osami Nagano, had not yet approved a surprise attack on Pearl Harbor, Admiral Yamamoto directed that intensive planning and training for such an attack was to be undertaken.
Japanese naval aircrews had already honed their war skills flying sorties against the poorly equipped and trained Chinese air force and army. However, Pearl Harbor offered special challenges to an enemy force proposing to use air-launched torpedoes. The harbor was comparatively shallow and a large area in the centre of the harbor was occupied by Ford Island. The American battleships were moored on the eastern side of Ford Island. The water area between the battleships and the eastern shore of the harbor was narrow. Japanese torpedoes would have to be redesigned for use in shallow harbor waters, and torpedo aircrews would have to learn to drop their torpedoes with great precision so that they would land in the narrow stretch of water between the eastern shore of the harbor and the battleships. The Japanese aircrews went about this training with great enthusiasm and dedication. By November 1941, they were ready for the attack.
On 3 November 1941, the Chief of the Japanese Naval General Staff finally gave his approval to Admiral Yamamoto's plan to attack the United States Pacific Fleet at its Pearl Harbor base.
The Japanese Carrier Strike Force departs for Hawaii
To distract the American government while it secretly positioned a powerful aircraft carrier strike force for the "sneak attack" on Pearl Harbor, the Japanese government had ordered its envoys in Washington to engage the American government in intensive diplomatic negotiations. Admiral Yamamoto's aircraft carrier strike force, under the command of Vice-Admiral Chuichi Nagumo, left Japan on 26 November 1941.
The fast and powerful aircraft carrier Akagi was regarded as the "Queen" of the Japanese Imperial Navy. It is shown here in 1941. It was the flagship of Vice Admiral Chuichi Nagumo for the attack on Pearl Harbor.
Preserving strict radio silence, Nagumo's carriers steered well clear of normal shipping lanes and headed for a stand-by point about 1,000 miles (1,600km) north of Hawaii. The carrier strike force comprised Japan's six largest fleet aircraft carriers, Akagi, Kaga, Soryu, Hiryu, Shokaku, and Zuikaku. Each of these aircraft carriers would later play a role in the major sea battles closely related to Australia's survival in 1942. The last two would take part in the crucial Battle of the Coral Sea. The first four would take part in the pivotal Battle of Midway. The carriers were supported by battleships, cruisers, destroyers and submarines.
Japan's Prime Minister Tojo threatens Britain and America with War
In the last week of November 1941, at a time when Admiral Nagumo's aircraft carriers were sailing towards Pearl Harbor with hostile intent, Japan's militarist Prime Minister, General Hideki Tojo, issued a blunt warning to Britain and the United States that Japan would "purge East Asia of US -British power with a vengeance". General Tojo's threat appeared on the front page of the New York Herald Tribune on Sunday, 30 November 1941, exactly seven days before the Japanese attack on America's Pacific Fleet at Pearl Harbor.
Despite the clear threat of war contained in Tojo's warning, and despite having no knowledge of the whereabouts of Japan's six largest fleet aircraft carriers, no steps were taken at Hawaii to bring the United States Pacific Fleet or the United States Army Air Corps to a state of war alert.
The Americans had broken the Japanese diplomatic code in September 1941, and were able to read coded messages from Tokyo to Japan's embassies in Berlin and Washington. The United States government knew that Japan had warned its diplomats in Washington that certain unspecified events would occur after 29 November 1941. However, the Americans believed that the warning fore-shadowed possible aggressive moves by Japan against the Philippines or British or Dutch colonial possessions in South-East Asia. Although they did not believe that an attack on Pearl Harbor was planned by the Japanese, the American commanders in Hawaii took steps to guard against possible hostile action by Japanese submarines and sabotage to military aircraft or installations on the main island of Oahu. To guard against sabotage, Major General Short lined up his aircraft on the runways as if for an inspection. They would prove easy targets for Japanese aircraft when the attack came.
The Order to attack the United States Pacific Fleet
When the Japanese aircraft carrier strike force reached its stand-by point north of Hawaii, it waited to receive either final confirmation to proceed with the attack on Pearl Harbor or an order to return to Japan. On 1 December 1941, the Japanese government reached a firm decision to make war on the United States. On 2 December 1941, a radio signal containing the code words "climb Mount Niitaka" was received by Vice Admiral Nagumo aboard his flagship Akagi. The code message was an order to attack Pearl Harbor on Sunday, 7 December 1941. The Japanese were well aware that most Americans at this time observed Sunday as a holy day, and they had carefully timed the surprise attack to occur when many Americans in Hawaii would be preparing for or attending church services.
Surprise was considered vital to the success of the attack on the American fleet. There would be no prior declaration of war to alert the Americans to their danger.
Admiral Nagumo's carrier strike force refuelled at sea on 5 and 6 December. Its approach to Hawaii was screened from American reconnaissance aircraft by low, dense cloud cover.
Japanese intelligence informed Nagumo on 6 December that the American battleships and a large number of smaller warships were in Pearl Harbor. However, Nagumo's primary targets were the American aircraft carriers, and they were all absent from the harbor. The Japanese believed that the American aircraft carriers Lexington, Saratoga, Enterprise and Yorktown were all based at Pearl Harbor at this time. Their intelligence was faulty. Having undergone routine dry-docking, Saratoga was at San Diego on the American west coast. Yorktown was stationed with the newly commissioned Hornet in the Atlantic at this time. Only Lexington and Enterprise were actually based at Pearl Harbor on 6 December 1941, and fortunately for the United States and Australia, both carriers were at sea when the Japanese attack took place. Despite this setback, Nagumo was under orders to proceed with the attack.
On 6 December 1941, President Franklin D. Roosevelt intervened personally in the cause of peace by sending a direct appeal to the Emperor of Japan. It fell on deaf ears in Tokyo. The Japanese government was determined on war and had no intention of recalling the Japanese carrier force.
Review of 20th Century Fox Pearl Harbor attack film "Tora! Tora! Tora! (1970)