Pearl Harbor timeline

1937

July

The Japanese Army invaded North China from

Manchuria, eight years of combat with the Chinese
began.

December

The gunboat USS Panay, while on routine duty in

Chinese waters, was attacked by Japanese aircraft.
We do not know if the attack was intentional or an
accident but Roosevelt looked for ways to punish
Japan . Nothing became of this incident because the
Japanese government apologized, paid for all
damages, and promised to protect American
nationals.

1938

October

With the continued German military rearmament

program and European leadership capitulation at the
Munich conference, President Roosevelt asked
Congress for $500 Million to increase America's
defence forces. This action was done because he
believed that Germany was a threat to the U.S. The
Japanese saw this build up as a direct threat to
their Empire because, the U.S. was the only country
in the Pacific which could impede their expansion.

1939

February

Japan continues its conquest of China by occupying

Hainan Island of the Southern coast. This occupation
improved Japans ability to interdict maritime trade
routes.

Because the U.S. was the primary military threat in

the Pacific, Japan had prepared war plans to deal
with this problem, the U.S. had similar war plans
aimed at Japan. The Japanese plan was to conduct
one large naval battle against the American Navy,
destroying it, resulting in the inability of the U.S. to
interfere with Japanese expansion through out Asia.
Admiral Isoroku Yamamoto assumed command of the
Japan's Combined Fleet in August of 1939. Having
lived in America for several years he knew
Americans, the type of people we were, he knew
that this war plan was impractical. He needed a new
plan which would remove the threat of U.S.
intervention from his flank.

1940

January

Some time between January and March 1940

Yamamoto devised his plan to destroy the U.S. Navy
in Hawaii and demoralize the American people.
Prange asks the question 'Why did Yamamoto think
that this attack would crush American morale since
he knew them?' but he does not answer his own
question. No actions were implemented to put the
plan in action.

July

Trade sanctions followed by a trade embargo were

imposed resulting in increased ill-will and additional
political problems with Japan. These trade actions
were imposed because Roosevelt was attempting to
stop Japanese expansion.

1941

January

Admiral Yamamoto begins communicating with other

Japanese officers, asking them if an attack on Pearl
Harbor would be possible. The final outcome of
these discussions was the attack was possible but
would be difficult.

* Secrecy and surprise were the two elements which

were most important to the success of this plan.
With that said one wonders how secure was the flow
of information around the Imperial Naval Staff,
because on January 27, 1941 Joseph C. Grew, the
U.S. Ambassador to Japan, wired Washington that he
had learned information that Japan, in the event of
trouble with the U.S., was planning a surprise attack
on Pearl Harbor.

No one in Washington believed the information, if

someone had believed this information, the Pearl
Harbor attack possibily could have been avoided.
While many thought that war was possible, no one
believed that the Japanese could surprise us.

Most senior American military experts believed that

the Japanese would attack Manila in the Philippine
Islands. Manila's location threatened the sea lanes
of communications as the Japanese military forces
moved south. Another thought to location of attack
was toward the north into Russia because of the
war in Europe between Germany and the Soviet Union.

February

As the Japanese were conducting preliminary planing

for the attack, Americans were preparing to defend
American property. Admiral Husband E. Kimmel,
Commander in Chief of the U.S. Fleet, and
Lieutenant General Walter C. Short, Commanding
General of the Hawaiian Department prepared Hawaii
for attack. Defence of the islands was an Army
responsibility though the Navy did play a major role
in preparing to repel an attack.

Adm. Kimmel planed on taking his fleet out of the

harbor and confronting the enemy at sea.

With this in mind both officers communicated with

their seniors in Washington attempting to obtain
additional men and equipment to insure a proper
defence of all military instillations on Oahu. At this
time, war production of the U.S. was still limited
resulting with the dispersal of material around the
world trying to fill everyones needs; Britain, Russia,
the Philippines and Hawaii.

March

Nagao Kita, Honolulu's new Consul General arrives on

Oahu with Takeo Yoshikawa, a trained spy. As the
military of both countries prepared for possible
war, the planners needed information about the
opponent.

The U.S. knew that Hawaii was full of Japanese

intelligence officers but because of our
constitutional rights very little could be done.
Untrained agents like Kohichi Seki, the Honolulu
consulate's treasurer, traveled around the island
noting all types of information about the movement
of the fleet. When the attack occurred the
Japanese had a very clear picture of Pearl Harbor
and where individual ships were moored.

Someone Talked

April

During the time period U.S. intelligence officers

continued to monitor Japanese secret messages.

American scientists had developed a machine, code

named 'Magic" which gave U.S. intelligence officers
the ability to read Japanese secret message traffic.
'Magic' provided all types of high quality information
but because of preconceived ideas in Washington
some data was not followed up on and important
pieces of the pre-attack puzzle were missed.

Japanese consular traffic was also intercepted

which provided additional intelligence. While the U.S.
had all the data needed to arrive at a clear picture
of Japanese intentions, the Navy had an internal
struggle between the Office of Naval Intelligence
and the War Plans Division about which department
should be the primary collection office. When the
War Plans Division was finally designated the first in
line for data, all of the Navys intelligence collection
was degraded .

To further complicate this problem the Army had its

own intell office, G-2. At times the Army and the
Navy did not talk to each other, again reducing the
ability to divine Japan's intentions. Finally,
Washington did not communicate all the available
information that was received to all commands, at
times thinking that such a transmission would result
in duplication. All in all the U.S. knew that Japan was
going to expand its war but the question remained,
where? If U.S. Intell people had communicated ,
preparations for the attack could have been
improved,

May

Admiral Nomura informed his superiors that he had

learned Americans were reading his message
traffic. No one in Tokyo believed that their code
could have been broken. The code was not changed.

If the Japanese had changed their code, the surprise

of the attack would have occurred as it did but
would we have been as poorly prepared or could the
result been worse? This mistake would have
impacted follow on actions through 1942.

July

Thought out the summer Yamamoto trained his

forces. His staff and the Naval General Staff
finalized the planning of the attack: what route to
travel on, how much fuel would be required for the
trip, what U.S. ships would be in the harbor and
where they would be moored.

The Japanese planners also had to coordinate their

own requirement of additional military action around
Indochina. Which action was more important and
which would provide the greatest gain had to be
worked out.

November

Tokyo sends Saburo Kurusu, an experienced

diplomat to washington as a special envoy to assist
Ambassador Admiral Kichisaburo Nomura, who
continued to seek a diplomatic solution.

Japan wanted the U.S. to agree to its southern

expansion diplomatically but if they were
unsuccessful , they would go to war.

On the 16th the first units,submarines, involved in

the attack departed Japan.

On the 26th the main body, aircraft carriers and

escorts, began the transit to Hawaii.

Japanese Aircraft carrier

December 7th

At 0750, Hawaiian time, the first wave of Japanesee

aircraft began the attack. Along with the ships in
Pearl Harbor, the air stations at Hickam, Wheeler,
Ford Island, Kaneohe and Ewa Field were attacked.

For two hours and twenty minutes, Japanese

aircraft bombed and shot up these military targets.
When the second wave returned to their carriers ,
2403 people had been killed and 1178 were wounded.
Eighteen ships of different sizes had been sunk or
damaged and 77 aircraft of all types had been
destroyed.

* only 29 Japanese aircraft were shot down by

American return fire, most during the attack of the
second wave. This number of planes downed is
significant but had the defenses of Hawaii been
prepared the number would have been greater.

Pearl burns