The attack on the US military installation at Pearl Harbor and other parts of Oʻahu by Japan’s Imperial military was one of the most successful surprise attacks in military history.
But an often-overlooked component of the successful attack is that the Japanese Empire had contracted with Bernard Otto Julius Kuehn, a German Nazi, to spy on the American military operations at Pearl Harbor from 1935 (an early ‘sleeper agent’ in espionage.)
The family had been contracted as agents of the Japanese government with the assistance of the Nazi Propaganda Minister Joseph Goebbels. The arrangement was promoted and negotiated by Goebbels as a byproduct of his relationship with Kuehn’s attractive 17-year old daughter, Susie Ruth. (Washington Times)
The execution of the plan was reminiscent of “one, if by land, and two, if by sea,” the phrase coined by American poet, Henry Wadsworth Longfellow in his poem, Paul Revere’s Ride.
It references the secret signal during Revere’s ride from Boston to Concord on the verge of American Revolutionary War alerting patriots about the route the British troops would take to Concord (two lanterns were shown, the British rowed over to Cambridge.)
The Kuehns arrived in Hawaiʻi in 1935; they started their spying then. 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.
Kuehn had houses in Hawaiʻi, lots of money, but no real job. Investigations by the Bureau and the Army, though, never turned up definite proof of spying. (FBI)
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.
Paid for his services, in three years he banked more than $70,000; one payment was $14,000 in $100 bills. They had houses in Lanikai and Kailua; these later served as the means of their intricate, yet simple, signaling system. (Pearl Harbor Board)
The Kuehn family took various means to gather information.
Kuehn would scout the ships at Pearl Harbor. Daughter Susie Ruth set up a beauty parlor and used it to gather gossip and random information from wives and girlfriends of the military men stationed at Pearl Harbor. Mother Friedel kept track of all the notes.
Ten-year-old Hans was dressed in a sailor suit and with his father would walk down near the docks. Many of the sailors thought the little guy was quite cute and some gave him unofficial “tours” of their ships.
Coached by his father, he would ask specific questions and observe everything he saw. Later he would be systematically debriefed by his parents.
The Kuehn family was not working alone; they worked with other Japanese spies attached to the Japanese consulate.
If the Consulate wanted to contact Kuehn, they would send a postcard signed “Jimmie” to his Post Office Box 1476 in Honolulu. (Pearl Harbor Board)
On December 2, days before the attack, he 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)
The set of signals contained eight combinations, each signal represented a number and each number represented the status of the naval fleet at Pearl Harbor.
No. 1 – battle fleet prepared to leave
No. 2 – scouting force prepared to leave
No. 3 – battle fleet left 1 to 3 days ago
No. 4 – scouting fleet left 1 to 3 days ago
No. 5 – air craft carriers left 1 to 3 days ago
No. 6 – battle fleet left 4 to 6 days ago
No. 7 – scout force left 4 to 6 days ago
No. 8 – aircraft carriers left 4 to 6 days ago
Signals were given that represented these respective code numbers. Part of how they did this was to shine lights out windows and hang sheets on the laundry line. These were done from their homes in Lanikai and Kailua (using lights in a dormer window.)
One light shining from the window between 7 and 8 pm meant No. 1; one light from 8 to 9 pm meant No. 2 and so forth for Nos. 3 and 4. Two lights shining from the window from 7 to 8 meant No. 5, etc. Hanging sheets on the laundry line carried the similar code.
An alternative display of the code used different patterns in the sail of Kuehn’s boat off Lanikai; a sail with/without a star and numbers at different hours represented corresponding references back to the code.
They also arranged the signal through KGMB Want Ads – different advertised items represented different numbers (ie Chinese rug, chicken farm, beauty parlor operator wanted, etc.)
Two other signaling means included garbage fires on a friend’s property on the side of Haleakala on Maui between certain times, representing different code numbers. Signals were also sent via shortwave radio. (Pearl Harbor Board)
Following the fateful attack of December 7, 1941, Honolulu Special Agent in Charge Robert Shivers immediately began coordinating homeland security in Hawaiʻi and tasked local police with guarding the Japanese consulate. They found its officials trying to burn reams of paper. These documents – once decoded – included a set of signals for US fleet movements. (FBI)
All fingers pointed at Kuehn. He had the dormer window, the sailboat and big bank accounts. Kuehn was arrested the next day and confessed, though he denied ever sending coded signals. (FBI)
On February 21, 1942, just 76 days after the tragic attack on Pearl Harbor, a military court in Honolulu found Bernard Otto Julius Kuehn guilty of spying and sentenced to be shot “by musketry” in Honolulu. His sentence was later commuted to 50 years of hard labor.
He served time in Leavenworth Penitentiary from December 1, 1942 to June 6, 1946 (when his sentence was commuted in order to deport him.) On December 3, 1948, he was deported to Buenos Aires, Argentina. (FBI)
Kuehn was one of 91-people convicted of spying against the United States from 1938 to 1945. (FBI)