In a History Today article from 2001, Dan van der Vat looks at the actual history rather than the film treatments of the Japanese attack on Pearl Harbour in 1941:
To recount what actually happened blow by blow, as in the exhaustive Tora, Tora, Tora!, is one thing; to use the event as the backdrop to an avowed fiction, as in From Here to Eternity, is equally legitimate. But to play fast and loose with history by presenting fiction as fact is at best confusing and at worse dangerous — especially when the event is still within living memory, affects current policy and needs to be understood by the young if the lessons of history are to be truly learned.
On Roosevelt’s ‘date that will live in infamy’, six Japanese carriers launched 350 aircraft to immobilise the US battlefleet at the very moment talks were due to resume in Washington. The Americans knew Japan’s propensity for surprise attack (Korea in 1895, the Russians’ Chinese enclave at Port Arthur in 1904, Manchuria in 1931, China in 1937). They were forewarned by their Tokyo embassy of the inclusion of Pearl Harbor in Japan’s war-plans, and they intercepted signals exposing its intentions. Yet the Japanese achieved strategic surprise. But their strategic blunder in not bombing repair facilities and fuel dumps spared the US Navy the crippling embarrassment of having to withdraw 2,200 miles eastward to the continental West Coast.
[. . .]
Initial American reaction to Pearl Harbor included not only rage at Japanese duplicity but also incredulity based on racism. Many witnesses insisted they had seen swastikas on the bombers; surely the Germans must have been behind such a sophisticated stroke. Inability to cope with the reality of America’s most spectacular lost battle led to a flourishing conspiracy industry which sprang up within hours of the bombing.
Even today, extreme revisionists claim that British frogmen came in on the midget Japanese submarines that almost gave the game away by trying to attack before the bombers. That at least one batch of intelligence intercepts from 1941 has not yet been released is taken as proof that they must conceal the ‘smoking gun’ the revisionists so stubbornly seek to this day.
Update: MHQ has the story of the most effective Japanese spy who reported on the comings and goings of US Navy ships at Pearl Harbour:
At 1:20 a.m. on December 7, 1941, on the darkened bridge of the Japanese aircraft carrier Akagi, Vice Admiral Chuichi Nagumo was handed the following message: “Vessels moored in harbor: 9 battleships; 3 class B cruisers; 3 seaplane tenders, 17 destroyers. Entering harbor are 4 class B cruisers; 3 destroyers. All aircraft carriers and heavy cruisers have departed harbor….No indication of any changes in U.S. Fleet or anything unusual.”
[. . .]
Astonishingly, such critical intelligence was not the work of a brilliant Japanese superspy who had worked his way into the heart of the fleet’s installation. Rather, Takeo Yoshikawa, a naval officer attached to the consulate and known to the Americans, had simply watched the comings and goings of the fleet from afar, with no more access than a tourist. He made little effort to cloak his mission, and almost certainly would have been uncovered if American intelligence had been more on the ball, or if America’s lawmakers had recognized the mortal threat Japan presented. Instead, he raised little suspicion, and his observations helped the Japanese piece together an extraordinarily detailed attack plan, ensuring its success.