The Ambassador in Japan (Grew) to the Secretary of State
Tokyo, January 27, 1941 — 6 p. m. [Received January 27 — 6: 38 a. m.] 125. My Peruvian colleague told a member of my staff that he had heard from many sources including a Japanese source that the Japanese military forces planned, in the event of trouble with the United States, to attempt a surprise mass attack on Pearl Harbor using all of their military facilities. He added that although the project seemed fantastic the fact that he had heard it from many sources prompted him to pass on the information.
Foreign relations of the United States: diplomatic papers
Department of State, United States of America.
On January 27, 1941, Grew secretly cabled the United States with information gathered from the Peruvian ambassador to Japan, Ricardo Rivera Schreiber that Japan was considering a surprise attack on Pearl Harbor, information that was declassified twelve years later.
Grew’s report was provided to Admiral Harold R. Stark, Chief of Naval Operations, and Admiral Husband Kimmel, Commander-in-chief of the U.S. Pacific Fleet, but it was discounted by everyone involved in Washington and Hawaii.
Was war inevitable?
Despite the continuous efforts on the parts of the diplomats of both Japan and the United States, the stress in the Far East continued to build pressure on any hopes of maintaining the peace. When war broke out in Europe in 1939, the United States realized it had purposefully neglected its Navy for too long. Treaties signed after the completion of the First World War had limited the size of the US Navy and its capacity to defend the nation in a two ocean conflict. There was just too much ocean and not enough strength to defend America’s sea power and commerce.
In 1940, authorization was given to build six Iowa class battleships (45,000 tons), five Montana Class battleships (58,000 tons which were never built), six Alaska Class cruisers (27,000 tons) an assortment of carriers and other ships and 67 submarines.
This huge shipbuilding program forced Japan to reassess her military situation.
Japan had withdrawn from all of the pre-war building agreements and treaties. This gave her a head start on building her ocean going fleet and the planes required to support her aggression. But she did not have the building capacity nor the oil reserves to match such naval strength. Her oil reserves alone could only sustain a way that would last two years and she could not replace the ships she might lose if she were not successful in the Pacific.
Plans were made in Japan to increase the speed and efficiency of creating the Greater East Asia Prosperity Sphere, a plan that was broadly supported and publicized by the military and right wing proponents in Japan. The implementation of this plan would be a strong force in uniting Great Britain, the Netherlands and the United States since all three controlled or influenced the territories containing the old and raw materials.
Throughout 1941, the shadow diplomatic efforts continued even though records now indicate the Japanese were merely using them as a delaying tactic for an inevitable conflict.
Shipyards across the United States began the massive process of expanding but the efforts would take time. Skilled builders needed to be trained and the raw materials needed to be produced and delivered. On paper, the Navy had the illusion of being strengthened. But only a few areas were capable of building the large numbers of vessels that would be needed.
The path to submarine dominance
Because of the dangerous environment that submarines would operate in, very few yards were certified to build the boats that would eventually be needed to fight the war that was coming.
In 1939, beginning with hull number 188 (USS Sargo) the boats were built primarily at the Electric Boat Company (73), the Portsmouth Navy Yard (73), Mare Island Navy Yard (17) and later at the Manitowac Shipbuilding Company (27) and the Cramp Shipbuilding Facility at Philadelphia (11).
Pearl Harbor Attack
Later in the year, five America submarines were in Pearl Harbor to witness the attack on the Pacific fleet. The submarine base is on the southern side of the harbor and you get an amazing view of the shipyard, part of battleship row and just beyond the opposite side of the harbor is Hickam Field.
The submarine, however is most vulnerable when it is on the surface. With no armor to speak of and her hatches opened and fouled with cables and other lines related to repair work, a submarine should have been an easy target. But the Japanese pilots were blinded with the same ambition as the people who they were attacking. The Battleships were one of their main goals and they avoided the small submarines. Just as importantly, they failed to attack any of the oil or submarine repair facilities. The same facilities that would service the deadliest weapon that would emerge from the battle ready to fight. The submarines.
There were only 22 submarines available that day to the Pacific fleet. Of the 22, 16 were the more capable fleet boats and 6 were the S-boats of an older vintage. But within months, they would grow in number. Of the Balao, Gato and Tench class boats, there would be a final number of 201 completed.
Submarines contributed in a manner that had not been envisioned. They were responsible for a large percentage of ship destruction that ultimately helped to starve Japan of the very reasons they began the war.
Future wars and technology will continue to evolve. Until the day comes when men learn to live in peace, it is certain that we need to be prepared for that certainty. My hope is that we will be as prepared as we need to in the face of that changing technology. We may find it hard to repeat the miracles that we performed in the middle of a shooting war.
By the way… Happy New Year