Photo/Illutration The former Sasebo wireless telegraphy station, believed to have relayed the code to attack Pearl Harbor, is seen on the anniversary of the attack on Dec. 7, 2021. (Eiji Hori)

SASEBO, Nagasaki Prefecture--The city government here plans to study and preserve the former Sasebo wireless telegraphy station, a century-old facility built by the Imperial Japanese Navy.

The station was constructed after the navy learned about the importance of radio communications during the 1904-05 Russo-Japanese War.

“Climb Mount Niitaka 1208,” the famed code used to initiate Japan’s attack on Pearl Harbor in 1941, is believed to have been transmitted through this station, which is commonly called the Hario radio transmission center.

The Sasebo city government included about 20 million yen ($136,000) in a supplementary budget submitted to the city assembly in September for the first full-scale study into the station starting by the end of March.

The municipality intends to continue spending on the project until March 2026 to examine the condition of the station, its quake-resistance strength, its materials and other details.

“We want to conduct a thorough inspection to assess the current status of the facility and how much it has deteriorated before proceeding to the next phase of repair and reinforcement,” a city official said.

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A semi-underground reinforced concrete building, referred to as the “telegraph room,” has a total floor space of about 1,256 square meters. Radio Tower No. 2 is seen in the back. (Takateru Doi)

The navy spent an estimated 1.55 million yen ($176 million at current values) to build the station between 1918 and 1922 in the southwestern part of the city separating Sasebo Bay and Omura Bay.

It was one of Japan’s first concrete structures that brought together cutting-edge civil-engineering and radio-communication technologies of the time.

After World War II, the Japan Coast Guard and the Maritime Self-Defense Force used the station until 1997.

In 2013, the central government designated the station as an important cultural property, calling it a modernization heritage symbolizing Japan’s technological development.

It consists of three 136-meter reinforced concrete towers. The diameter of each tower base is about 12 meters.

The towers form an equilateral triangle, 300 meters per side, with a communication facility referred to as the “telegraph room” built in the center.

Each tower cost an estimated 300,000 yen ($35 million at current values) to build.

The station was mainly used for communications with navy units deployed to China, Southeast Asia and the South Pacific Ocean.