Takeo Yoshikawa, a Japanese spy, arrived in Honolulu on March 27, 1941, aboard the Japanese liner Nitta Maru. His papers identified him as Tadashi Morimura, the name he was always referred to while in the Islands (and subsequent investigative records.) (He’ll be referred to here by his real name, Yoshikawa.)
Born on March 7, 1914, Yoshikawa had been approached in 1936 to work as a civilian for Japan’s naval intelligence service: “Since I had been studying English, I was assigned to the sections dealing with the British and American navies. I became the Japanese navy’s expert on the American navy.”
“I read everything; diplomatic reports from our attachés, secret reports from our agents around the world. I read military commentators like Hanson Baldwin (New York Times military affairs editor.)” Yoshikawa also studied Jane’s Fighting Ships and memorized the silhouettes of all the American ships, something that would later prove critical. (Savela)
Posing as junior diplomat, Yoshikawa was to keep current on the status of the US fleet and its anchorages, reporting his observations to Tokyo by coded telegraph messages. Thanks to Hawaiʻi’s large Japanese-American population, Yoshikawa easily blended in.
When Kita briefed Yoshikawa, he reminded him, “Don’t make yourself conspicuous; maintain a normal, business-as-usual attitude, keep calm under all circumstances; avoid taking unnecessary risks; stay away from guarded and restricted areas and be aware of the FBI.” (Prange; Savela)
In keeping with his cover, Yoshikawa avoided illegally entering military bases or stealing classified documents. He shunned cameras and notepads, relying instead on memory. He supplemented his observations with items of interest gleaned from daily newspapers.
Yoshikawa familiarized himself with the principal Hawaiian Islands and their military installations, which were concentrated on Oʻahu. He frequently relied on a hired cab driven by John Mikami, a Japanese-Hawaiian who often performed chores for the consulate. (Deac)
Other times, Yoshikawa was chauffeured by Richard Kotoshirodo, a consular clerk. It did not take long for Yoshikawa to scout out the various US Army and Navy bases on central, southern and eastern Oʻahu. Predictably, the focus of his attention was Pearl Harbor, the nearly landlocked US Pacific Fleet anchorage on the south coast of the island.
The assignment fit into a plan outlined in January 1941 by Combined Fleet Commander Isoroku Yamamoto. The plan called for an aerial assault on Hawaiʻi as the opening move of a war between the United States and Japan. Yoshikawa was to become his country’s only military spy in the islands and Yamamoto’s most valuable source of current information on Oʻahu. (Deac)
And with its relatively open landscape, sloping elevations, and limited restrictions on movement, he readily compiled useful intelligence. His encyclopedic knowledge of US ships and his methodical charting of their movements made his reports all the more valuable. His contribution to the Japanese effort was ultimately “an important one.” (Savela)
Yoshikawa did not work alone. Later joining him in espionage was a ‘sleeper agent’ Bernard Otto Julius Kuehn and his family, Nazi spies sent to the Islands by Nazi Propaganda Minister Joseph Goebbels. (Washington Times)
The Kuehns arrived in Hawaiʻi in 1935, they blended in, and waited; no one seriously suspected that Caucasians would carry on espionage for the Empire of Japan, so Kuehn, his wife Friedel, their daughter and son, Hans Joachim, were virtually inconspicuous as a white family on the windward side.
However, every member of the family contributed towards collecting and documenting military activities at Pearl Harbor from 1935 right up to the day the bombs fell from Japanese aircraft.
On December 2, days before the attack, Kuehn provided specific – and highly accurate – details on the fleet in writing. That same day, he gave the consulate the set of signals that could be picked up by nearby Japanese submarines. (FBI)
At midafternoon on December 6, Yoshikawa made his final reconnaissance of Pearl Harbor from the Pearl City pier. Back at the consulate, he coordinated his report with Kita, and then saw that the encoded message was transmitted to Tokyo.
At 1:20 am 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 US Fleet or anything unusual.” (Savela)
In the early morning of December 7, 1941, Japanese pilots flew toward the island of Oʻahu from six aircraft carriers (the Akagi, Kaga, Soryu, Hiryu, Shokaku and Zuikaku;) two waves of planes attacked various military installations on Oʻahu.
The prearranged coded signal “East wind, rain,” part of the weather forecast broadcast over Radio Tokyo, alerted Japanese Consul General Nagao Kita in Honolulu, and others, that the attack on Pearl Harbor had begun.
The first wave of 183-planes (43-fighters, 49-high-level bombers, 51-dive bombers and 40-torpedo planes) struck its targets at 7:55 am. The second wave of 167-Japanese planes (35-fighters, 54-horizontal bombers and 78-dive bombers) struck Oʻahu beginning at 8:40 am.
The Japanese consulate staff locked the consulate doors and began burning all their codebooks and classified material. “Smoke was pouring out of the chimney.” At about 9:30 am, December 7, the consulate staff was arrested and later shipped to Phoenix, Arizona.
By 9:45 am, the Japanese attack on Oʻahu was over.