Battleship Nagato

Nagato (長門) was the lead ship of the Nagato-class battleships, ordered for the Imperial Japanese Navy on 12 May 1916 and laid down at the Kure Naval Arsenal on 28 August 1917. She was launched on 9 November 1919 and commissioned on 25 November 1920. As the first battleship in the world to mount 41 cm (16.1 in) guns — eight of them in four twin turrets — she was considered one of the world's most powerful warships at the time of her completion, earning a place in the so-called "Big Seven" alongside her sister Mutsu, the British HMS Nelson and Rodney and the three American Colorado-class battleships.

Nagato and her sister ship Mutsu became immensely popular symbols of Japanese naval power, and their profiles were familiar to every Japanese citizen. During the interwar period, Nagato underwent a major reconstruction from 1934 to 1936, during which her superstructure was rebuilt in the towering pagoda mast style, her hull was bulged for improved torpedo protection, and her machinery was upgraded to raise speed. She served as the flagship of the Combined Fleet for most of the interwar period and was the command ship of Admiral Isoroku Yamamoto during the Pearl Harbor attack of 7 December 1941; the coded order to proceed, "Niitakayama nobore" (新高山登れ, "Climb Mount Niitaka"), had been transmitted from her on 2 December while she lay at anchor at Hashirajima.

Despite her symbolic importance, Nagato saw relatively little direct combat during the Pacific War. She participated in the Battle of Midway in June 1942 but was not engaged. She was transferred to Truk in mid-1943 and participated in the Battle of the Philippine Sea in June 1944, where she was strafed by American aircraft but not damaged. During the Battle of Leyte Gulf in October 1944, she was part of Admiral Kurita's Center Force and sustained two bomb hits in the Sibuyan Sea engagement. By early 1945, critically low on fuel, she was moored at Yokosuka and effectively immobile for the remainder of the war. She was the only Japanese battleship still afloat when the war ended on 15 August 1945.

After the Japanese surrender, Nagato was taken under U.S. control at Yokosuka. She was selected as one of the target vessels for Operation Crossroads, a series of nuclear weapon tests conducted by the United States at Bikini Atoll in the Marshall Islands during the summer of 1946. In the first test (Shot Able, 1 July 1946 — an air burst), Nagato was positioned 1,500 meters from ground zero and survived with minor damage. In the second test (Shot Baker, 25 July 1946 — an underwater detonation), she was placed 870 meters from ground zero. She rode out the blast column and initial wave with a slight list, but over the following five days her list gradually increased as radioactive sea water flooded her compartments. She capsized and sank during the night of 29–30 July 1946, going to the bottom without being witnessed by any Americans.

Today Nagato's wreck rests upside-down on the floor of Bikini Atoll lagoon at a depth of approximately 52 meters (170 ft). Her four large propellers and two rudders, at around 33 meters, are the first features encountered by divers. The Bikini Atoll lagoon was designated a UNESCO World Heritage Site in 2010, and the Nagato wreck is considered one of the most historically significant and challenging wreck dives in the world.