Former Sasebo Radiotelegraph Station Facility (Hashima Transmission Station)

Overview

The Hashima Transmission Station, located in Hashimaechuo-machi, Sasebo City, is a former radio transmission station built by the Imperial Japanese Navy. Construction began in 1918 (Taisho 7) and was completed in 1922 (Taisho 11). At the time, shortwave communication technology was susceptible to ionospheric interference, increasing the need for longwave communication, leading to the construction of the Hashima Transmission Station. The three radio towers stand 135 meters tall, with a base diameter of approximately 12 meters and a thickness of 76 centimeters. Arranged in an equilateral triangle approximately 300 meters apart, their grandeur is visible from afar. While sometimes associated with the transmission of the Pacific War code "Niitakayama Nobore 1208," it's believed that the Funabashi Transmission Station in Funabashi City, Chiba Prefecture, and the Isami Transmission Station in Isami Village, Hekikai District, Aichi Prefecture, actually sent the message. During the Pacific War, medium and shortwave communication became primarily used, diminishing the importance of the Hashima Transmission Station. Towards the war's end, the radio towers were even used as food storage. After World War II, it continued to operate as a radio facility for the Japan Maritime Self-Defense Force and the Japan Coast Guard, finally ceasing operation in 1997 with the completion of a successor facility. In 2013, the three radio towers, along with two buildings (the telegraph room and the oil storage tank) and the surrounding land, were designated as Important Cultural Properties. Now open to the public, visiting hours are 9:00 AM to 4:00 PM, weekdays and weekends. Tower No. 1 is viewable from the outside only. The oil storage and telegraph room interiors are open to visitors. Access to the interior of Tower No. 3 is limited to the entrance area. Future plans include the development of visitor walkways and information facilities throughout the area, with plans to eventually open the interior of all towers to the public. The Hashima Transmission Station is a significant historical asset that played a crucial role in Japan's modernization, and its majestic appearance is sure to impress visitors.