The Pearl Harbor Spy


By: Mark Loproto

The Japanese attack on Pearl Harbor seemed to go off without a hitch. The American Pacific Fleet was completely unprepared and the Japanese knew exactly what to hit them with. Even with general knowledge about the Pearl Harbor and Battleship Row, for such a plan to come together so perfectly, it would seem that Japan had something else going for them. Digging deeper into the history of Pearl Harbor and the key players, we learn that Japan also had Takeo Yoshikawa, a man who, after the attack, would be revealed as the spy who had helped in its planning.

The Initial Report

Hours before the attack commenced, just after 0100 on December 7th, the Japanese aircraft carrier Akagi was provided with information that would be vital to their mission. Vice Admiral Chuichi Nagumo was handed a message that would be the undoing of Pearl Harbor:

“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 US Fleet of anything unusual.”

How had the Japanese obtained such information without being spotted by the American vessels scouting the harbor? Takeo Yoshikawa had been positioned there, hidden among the tourism of Oahu. He didn’t have access to the military base, but his view was enough to know the comings and goings of the vessels there.

Infiltrating Hawaii

There were no eyes on Yoshikawa, as the mild-mannered gentleman wasn’t considered a threat by American leaders. He had entered the country under the pseudonym Tadashi Morimura. Nippu Jiji, a Honolulu newspaper printed in English-and-Japanese, reported the arrival of Morimura, a worker at the Japanese consulate who was to assist in expatriation applications. Before he was Morimura, Yoshikawa was a member of the Japanese Naval Academy who, in 1935, was promoted to ensign before a stomach illness allegedly ended his military career.

Yoshikawa claimed that he was approached in 1936 to work for Japan’s naval intelligence as a civilian. Four years later, he received an assignment in Hawaii on an intelligence mission: to spy on Pearl Harbor. Without interference from locals or the American government, Yoshikawa was able to move about the island, collecting information without entering any restricted area to avoid drawing attention.

It was Yoshikawa’s message delivered to Nagumo aboard the Akagi that pointed the fleet and attacking fighters to Battleship Row.

As the Smoke Cleared

Once it became known with certainty that Japan had struck Pearl Harbor, Yoshikawa was detained and interrogated, though his strong will kept him from divulging any information about his mission. To the Americans, he was still Morimura. He remained in United States captivity until 1942, when he was repatriated to Japan through the prisoner exchange of the SS Gripsholm.

In 1993, many years after his time in Hawaii, Yoshikawa passed away. Though it was his actions that helped orchestrate Japan’s attack on Pearl Harbor, there were no celebrations or accolades provided for his service. He simply passed away, his memory embedded in a devastating day in history.

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