Secret Eye (eBook)

7. OAHU, HAWAII

The Army Signal Corps established the aircraft warning service (AWS) to protect American territories, including Hawaii, from surprise attacks. The installation uses a portable SCR-270 radar, created at the Signal Corps Laboratories in Monmouth, New Jersey. Known as the first long-range radar systems deployed by the United States to protect its territories, the United States deployed the AWS on Oahu prior to the mission by Tizard.

They deployed the SCR-270Bs on the north shore (Haleiwa)—on the northern tip of Opana Point —at Mount Kaala on the northwest side—and at Koko Head in the southeast, creating a ring around the island. The installation provided a radar ring of 150 miles around Oahu, with the Opana Point system having an unencumbered view of the Pacific Ocean.

“We are prepared to begin the deception, Admiral Yamamoto,” said Onishi.

“We have kept this from the captains of our ships, correct?” questioned Yamamoto.

“There are only three people aware of your plan,” reminded Onishi. He had concern that this reminder would raise the anger of Yamamoto.

Yamamoto had convinced the Supreme War Council to change Japan’s long-standing defensive military posture to an offensive posture. He hoped that the United States and Britain would not detect this monumental shift in military policy. Yamamoto then concentrated Japan’s core air power into a single tactical formation, the Kido Butai, something never done in military world history. No country could now match Japan’s ability to project power in the region, and he knew the Americans would be ready to beg for mujōken kōfuku. For Yamamoto’s plan to succeed, he would have to make the enemy believe that the Imperial Navy was staying close to its territorial waters, while the Kido Butai moved to attack Pearl Harbor. 

While completing the final preparations for the surprise attack on Pearl Harbor, Yamamoto knew that total operations security (OPSEC) was imperative, and that he would need to leverage the Post, Telegraph, and Telephone (PT&T) Ministry, radio intelligence using RDF, and human intelligence assets in Hawaii to sow the seeds of deception in the West. The most difficult tactical problem to solve was avoiding the detection of his fleet by enemies of the Imperial Japanese Navy when they leave Japanese territorial waters. The American and British radar systems kept track of the movements of the Japanese Navy by intercepting and decoding radio transmissions from ships, official diplomatic communications, and through newly deployed radar installations around the South Pacific.

“Recently, the British listening post in Hong Kong detected our fleet movements and our leadership is concerned this detection may compromise our attack strategy on Oahu,” Yamamoto said. “Our deception must be effective, or we will fail.”

Onishi shook his head in agreement.

“We must use the kichiku eyes and ears against them. Make them believe we are somewhere we are not,” concluded Yamamoto. “They must believe we are still in our defensive military posture, not offensive as we have become.”

“May I share these plans with our captains so the deception can begin?” asked Onishi.

“Yes,” responded Yamamoto, “but you must speak to each captain alone and in person. We do not want to jeopardize this plan by sending written or radio communications. The code name of this operation will be Dragon Fire.”

Yamamoto dismissed Onishi and began reviewing his maps to determine the safest route to Tankan Bay.

Henry Simpson entered the Oval Office to provide his daily briefing to the president.

“Good morning, Mr. President, Mr. Vice President.” Stimson was still standing, waiting for Roosevelt’s aid to help him to the chair facing the sofa. The room cleared, leaving Stimpson and Vice President Wallace on the sofa. 

“Good morning, Henry. Please sit down,” the president said warmly. “What is new with Japan?”

“Sir, the Japanese are preparing for training exercises in their home waters. Our COMINT folks,” said Simpson referring to the communications intelligence department, “just decoded a message from Tokyo to Ambassador Numara. The letter shows that they are preparing for an exercise to test communications protocols,” Stimson concluded.

“Should there be concern?” the president asked.

“No, sir,” Stimson assured. “From what we can decipher, this is a routine exercise and may last a month or two. We will continue to monitor the exercises closely.”

“How about checking with our British friends?” Roosevelt suggested. “Perhaps they can monitor Japan’s progress and share what they find.”

“Already working on that, sir,” reported Stimpson. “Our team in Singapore and the British listening post in Hong Kong should give us independent data that we can use to verify the Japanese are just having military exercises. Our folks in Hawaii are listening.”

“I do not trust the Japanese,” warned Roosevelt. “We know them to rely on surprise to gain the upper hand. Now that the oil embargo of Japan is fully out in the open, we must observe them cautiously.”

“I fully agree, sir,” assured Stimson. “Our communications people are the best in the world, and now that we can decrypt any message sent to the ambassador, we will have the upper hand.”

“How is the present the British gave us working out?” the president inquired.

“Loomis and his team are working on integrating the new cavity magnetron unit into the CXAM sets. The expectation is that our carriers will increase our detection range to one hundred nautical miles from the fifteen nautical miles in previous sets. Mr. Tizard and his team gave us a significant advantage over any adversaries,” said Stimson.

“I hope and pray we will not have to use our radar to protect ourselves, but I fear we have cast our dye in this matter,” said the president ominously. “Anything else, Henry?”

“No, sir. Thank you for your time this morning. Give my best to your wife, sir, Mr. Vice President. Good day to you both.” Stimson withdrew from the Oval Office.

“What do you think, Henry?” asked the president.

“I agree with you, sir. We should not trust the Japanese; they are crafty bastards,” Wallace fired.

“Time is ticking before they thrust us into this conflict, one way or another,” warned Roosevelt.

“I have been monitoring the communications of the Japanese fleet, sir,” said a petty officer at COMINT. “All I have heard is regular operational training communications with other ships in the fleet.”

“Very well then,” said the lieutenant, “I will take this report to the captain.”

The message quickly rose through the chain of command as the president ordered regular reports on the Japanese fleet and its movements. Admiral Husband E. Kimmel had recently accepted the promotion to commander-in-chief of the United States Fleet (CINCUS) and commander-in-chief of the United States Pacific Fleet (CINCPACFLT) after the forced resignation of James O. Richardson. The previous year, President Roosevelt had moved the fleet to Pearl Harbor as a deterrent to the Japanese without consulting his military leaders. Richardson believed the Navy and country lacked preparedness for war with Japan, and placing the fleet in such a forward position was dangerous and asking for a surprise attack. Instead of being promoted after voicing his concerns, Roosevelt fired him.

Admiral Kimmel read the communications report.

“Just as we expected,” said Kimmel. “The Japs should be busy for the next few months. This is the confirmation that shows the fleet is moving forward with the training exercises. I will have to send that bottle of rum to the team in Singapore.”

The MIT campus in Cambridge housed the Rad Lab, or the radiation laboratory. They named it so to make people believe that it conducted nuclear research and not research in radar. They appointed Alfred Loomis the director of the lab in December 1940. Taffy Bowen was staying in the United States to help integrate the cavity magnetron into the existing US technology assets. Alfred Loomis entered the lab to speak to his team.

“Gentlemen,” Alfred began, “we have an enormous challenge in front of us. The Japanese have been working on radar for years, just as we have, but it does not appear to be as far along. You have been handpicked to work in this top-secret environment, and I must warn you that everything you see, do, or say here must stay within these walls. Our challenge is monumental, but through the gift of the cavity magnetron from our British allies, we will not fail. Let me introduce Mr. Taffy Bowen, who has graciously offered to stay around for a while to help us get up and running.”

All in attendance applauded.

“Thank you, my Yank friends,” said Taffy Bowen. “Our primary focus will be the development of new radar systems based on microwave technologies. Your country has made significant strides in VHF and UHF radar technologies, but power requirements have hampered your system’s usefulness to our warriors in the field. That is where our cavity magnetron has made an immense difference in your power output.”

Bowen explained the design and inner workings of the cavity magnetron and how it would win the war for the Western alliance.

Invented in 1910 by H. Gerdien,...