At 6:00AM on November 21 of 1954, Japanese Coast Guard Patrol Ships Oki and Hekura arrived near Takeshima. The ships straddled the territory north-to-south before conducting a survey (i.e. the 30th Special Control Campaign). The Hekura came under bombardment by five shells between 6:58 and 7:01AM while approximately 3.2 nautical miles (NM) northwest of the Western Islet (Ojima). The shells fell into the sea approximately 1NM away without damaging the ship. At this juncture, the Japanese Coast Guard confirmed that a wireless radio mast had been erected in the center of the Eastern Islet (Mejima) as well as the presence of 14 - 15 guards in that vicinity. One wireless radio pole on the eastern side of this islet was flying the Korean flag. (Ref.1)

Ref. 1: “8th Regional Coast Guard Headquarters Officially Classified Document No. 275 (November 24, 1954)” (Japan Coast Guard, 8th Regional Coast Guard Headquarters disclosed document)

Related documents
20th Session of the Diet (Parliament of Japan), House of Representatives, Cabinet Committee, Minutes No. 2