What was the nature of the surprise in
December 1941 that accounted for the Japanese success
in both crippling the American pacific fleet in Pearl
Harbor and destroying America's only wing of bombers
at Clark Air Force Base in the Philippines?
The surprise was
technological. The attack on Pearl Harbor took place
on the morning of December 7th 1941; the attack on Clark
Air Base in the Philippines occurred hours later. The
real surprise was not the intentions of the Japanese
military, or even the proximate time, it was the ability
of Japanese pilots and ordinance to successfully execute
By December 2, 1941, the US had ample warning from its
code-breaking operations (including MAGIC), its traffic
analysis of Japanese radio communications and other observable
activities (such as embassy activities and military radio
silence) to conclude that Japan was preparing for war
in the Pacific. US Naval intelligence, for example, had
interpreted the ominous change in Japanese call signals
for all its ships on December 1— and efforts to obscure
the whereabouts of its aircraft carriers from US surveillance—
as ominous war signals. So the proximate time of attack
was not a total surprise. Neither was the likely targets.
There was a shortlist of four targets: the two most likely
being Pearl Harbor, where the US Pacific fleet was stationed,
and Clark Air Force Base, where virtually all of the US
bombers were stationed.
What was unexpected was Japanese capabilities. In the
case of Pearl Harbor, US military intelligence had assessed,
based on observation of Japanese air shows, that Japan
did not have the capacity to launch torpedoes from airplanes
in shallow water. Torpedoes in 1941 were usually deployed
in deep water, so their motors could start to propel to
the surface before they hit the ocean floor. If Japanese
pilots did not have the technology and skill to launch
torpedoes in shallow water, the safest place for the US
battleships would be in the shallow waters of Pearl Harbor.
If Japan tried to dive bomb the ships in Pearl Harbor,
naval anti-aircraft gunners could them down as they circle
directly overhead. So, marshaled in the presumably safe
harbor, the fleet was kept on an alert 1 status (the lowest
of three alerts). What was unexpected was that Japanese
pilots had been secretly trained to skim their torpedoes
in shallow water, and that surprise left the fleet, no
matter what its level of alert, vulnerable to being sunk
from afar by carrier-launched planes. So all of America's
battle ships were sunk or severely damaged.
At Clark Air Force base, there could be no possible surprise
about Japan's intention. Japan had already attacked the
US, nine hours earlier. The US command assumed, however,
its bombers were safe because, with the Japanese carriers
now known to be in Hawaii, the nearest available Japanese
bombers, based in Taiwan, could not reach the Philippines
without mid air refueling. And US intelligence had assessed
that these land-based bombers could not by refueled in
mid-air by Japanese pilots. So the U.S. left its only
wing of bombers parked, wing to wing, in the open. What
was unexpected was that Japan, like the US, had perfected
mid-air fueling techniques. In both cases, the US were
surprised, not by the intentions of the Japan, but by
Collateral Question: Why was there a technological
Two variations of Deception.
The picture that emerged by 1941 in Washington of a primitive
Japanese air force that lacked both the technology and
pilot training for refueling in mid-air, launching torpedoes
in shallow water, conducting long-range missions proceeded
both from self-deception and other-directed deception.
The former grew out of the stereotyped of Asian incompetence.
The latter, out of a deliberate Japanese program to project
weakness prior to the attacks.
The Japanese-directed deception used British and American
military attaches to reinforce the picture of weakness.
While concealing its modern Zero fighter, Japan displayed
its antiquated and obsolescent planes at air shows. When
western attaches were invited at Japanese air bases, exhibitions
of flying incompetence were purposefully staged for them.
As one of Japan's leading strategists later explained
"Foreign observers saw only what we allowed them to see".
And western attaches (and other spies) were mis-briefed
by Japanese air ministry officials on the difficulties
of training Japanese pilots to fly solo. The resulting
assessment of incompetence closely fitted in with and
reinforced the preconceptions that most foreign attaches
had about the Japanese. Through this disinformation, and
reinforcement of stereotypes, Japan caught the United
States totally unprepared for its aerial attack on presumably
safe harbors and out-of-range airfields.