This article has been extracted from Ultra in the Pacific by John Winton and is reproduced here by permission of Pen and Sword Books Ltd.
The Japanese air attack on Pearl Harbor on Sunday, 7 December 1941, was a shocking blow to the self-esteem of the entire American nation. There was an understandable desire to hunt down those who were held to be to blame. Admiral Husband E Kimmel, Commander-in-Chief of the Pacific Fleet, and General Walter C Short, the Army Commander at Pearl Harbor, were obvious scapegoats and were duly treated as such.
Admiral Kimmel took on his shoulders the main burden of responsibility for Pearl Harbor, just as the captain is ultimately answerable for everything that happens to his ship.
‘Immediately after Pearl Harbor’, Kimmel said later, ‘I felt that, no matter how hard and how conscientiously I had tried, I had not been smart enough, and to that extent, must accept blame for Pearl Harbor.’
However, Kimmel expected to be given another assignment. He certainly did not expect to be so severely criticized by the Roberts Commission that he would feel compelled to offer his resignation by the end of January, 1942. But, as the several seemingly interminable Pearl Harbor enquiries and investigations dragged on over the years, it began to emerge that Kimmel was much more offended against than offending. When he discovered the truth, he was justifiably angry.
‘Since learning that definite information of the Japanese intentions to attack the United States was in the hands of the War and Navy Departments and was not supplied to me, I now refuse to accept any responsibility for the catastrophe.’
The truth was that there had been plenty of intelligence in the months before Pearl Harbor which, with hindsight, can clearly be shown to have revealed Japanese intentions. The failure, if it was a failure, was in evaluating that intelligence and thereafter promulgating it to the operational commanders at Pearl Harbor. Understandably, the feeling of personal failure after Pearl Harbor was especially keen among the naval intelligence community. Layton, who had been Kimmel’s Intelligence Officer, expected to be relieved and sent back to the States. He asked Nimitz if he could go to sea in command of a destroyer, but Nimitz said:
‘You can kill more Japs here than you ever could in command of a destroyer flotilla’.
Like other officers at Pearl Harbor, Layton was surprised and grateful to find that Nimitz was not going to carry out a witch-hunt against Kimmel’s staff.
Pearl Harbor looking southwest, 30 October 1941.
Rochefort, who had been at Pearl Harbor since June, 1941, also felt personally responsible, believing that it was an intelligence officer’s purpose to inform his commander of enemy intentions.
‘I took it as my job,’ he said, ‘my task, my assignment that I was to tell the Commander-in-Chief today what the Japanese were going to do tomorrow.’
Station HYPO, the communications intelligence center on Oahu Island, renamed ‘Combat Intelligence Center’ at Rochefort’s insistence for security reasons, was one of three US Navy Communications Intelligence Centers – the others being Station NEGAT in Washington DC and Station CAST at Cavite in the Philippines. It had begun as a one-man organization in 1936 and grew steadily to become the CIC of the Joint Intelligence Center, Pacific Ocean Area.
Pearl Harbor Anchorage - 7.55 am - 7 December 1941.
‘Combat Intelligence’ eventually had so many meanings it became virtually meaningless. But the CIC was originally intended to obtain information on, and maintain a plot of, all vessels. Allied as well as German and Japanese, in the Pacific. In time, under Captain Rochefort, it evolved into a complex and subtle organization evaluating and interpreting all forms of Radio Intelligence.
On the morning of 7 December 1941, CIC became the clearing house for all manner of reports, almost all completely unfounded; of enemy activity. One of the most difficult peacetime problems in training intelligence personnel was the impossibility of simulating a flow of detailed, apparently well-authenticated, misinformation.
In the first forty-eight hours after Pearl Harbor, the CIC had a flood of misinformation which left them ever afterwards with a healthy mistrust of ‘eyewitness’ accounts, not only from excited civilians but also from experienced Service personnel, both Allied and enemy.
Pearl Harbor Day Attack.
Japanese parachute troops were reported to have landed and to be engaged in a fierce pitched battle with US Marines. The uniforms worn by these mythical Japanese were described in the most minute sartorial detail. Strange vessels were reported arriving offshore, a large enemy fleet had been seen south of the islands and at least one Direction/Finding bearing (later judged to be ambiguous and inconclusive) was obtained. One officer sighted a dirigible over Honolulu, two degrees to the right of the moon and three degrees below it.
To make matters more confusing, there were seemingly improbable reports of submarines in Pearl Harbor – but Japanese submarines did indeed take part in the attack.
Emperor Hirohito on military parade after Pearl Harbor attack.
'Since learning that definite information of the Japanese intentions to attack the United States was in the hands of the War and Navy Departments and was not supplied to me, I now refuse to accept any responsibility for the catastrophe.'
Admiral Kimmel at first accepted the blame for being taken by surprise. However, he was to change his mind when he learned that Japanese intentions had been known, but not passed to him.
Admiral Chuicki Nagumo commander of Japan’s strike force for the attack on Pearl Harbor.
Japanese planes prepare to take off for the attack on Pearl Harbor, 7 December 1941.
Newspaper headlines, announcing the declaration of war on the Japanese.
Ultra in the Pacific - How Breaking Japanese Codes and Ciphers Affected Naval Operations Against Japan
Ultra was the name given to information gained from deciphering the messages passed by the enemy in code during the Second World War. Fortunately for the Americans, the Japanese believed that it was not possible for Westerners to learn their language.
The war in the Pacific has had many chroniclers but the secret of Ultra remained guarded for many years and only recently has it become possible to assess in detail the effect it has on the campaign. John Winton’s expert analysis of the records now available are here combined with his encyclopedic knowledge of the naval history of the Second World War to tell, for the first time, what exactly the Allies did learn from Ultra in the Pacific War and to what use that knowledge was put. The result is a fascinating story told with the zest and pace one might expect from an author who is both a highly respected historian and a first-class novelist.