The Japanese battleship Kongō's nickname 'Indestructible Diamond' was proven wrong by an American submarine

The Japanese battleship Kongō was known by several intriguing nicknames, including "Indestructible Diamond," "Indra's Spear," and "Divine Thunder." Alongside these titles, she saw extensive service throughout both World War I and World War II.

Here is the tale of one of the most heavily armored battleships of her era.

Construction of Kongō

The construction of the battlecruiser Kongō commenced in January 1911, under the design of British naval engineer George Thurston. She was the only ship of its class built in the United Kingdom, with her construction occurring at Barrow-in-Furness in Cumbria, England. The other three battlecruisers of this class were manufactured in Japan.

The development of Kongō was overshadowed by scandal. In January 1914, a leaked telegram revealed that Japanese officials had been accepting kickbacks from German and British armaments companies in exchange for using their products. This disclosure resulted in the resignation of the entire government of Prime Minister Yamamoto, along with several senior business executives. Additionally, Japanese Vice Adm. Matsumoto Kazu was court-martialed and sentenced to three years in prison due to his involvement.

Kongō was loaded with armaments

Kongō was outfitted with eight 14-inch heavy-caliber main naval guns, arranged in four twin turrets. These guns could fire both armor-piercing and high-explosive shells and were the first 14-inch guns worldwide to be installed on a naval ship. It was crucial for the Japanese military to have confidence in its ability to outgun adversaries, and Kongō 's armament largely guaranteed that advantage.

The battleship’s secondary battery included 16 six-inch .50-caliber guns housed in single casemates, along with eight three-inch guns and eight 21-inch submerged torpedo tubes. Additional firepower was added in 1929 when the ship was upgraded from a cruiser to a battleship, and by October 1944, its secondary armament featured eight six-inch guns, 122 Type 96 anti-aircraft rapid-fire cannons, and eight five-inch guns.

Service during World War I

Kongō was formally commissioned in August 1913 as a battlecruiser, and it didn't take long for her to be pressed into service. At the outset of the First World War , she was sent to patrol German lines of communication at sea, before supporting Japanese units during the Siege of Tsingtao . Following the British defeat of Germany at the Battle of the Falkland Islands , there was little need for Kongō . As such, she was either kept at Sasebo Naval Base or on patrol near China for the remainder of the conflict.

Following WWI, world powers didn't want to see another conflict and the Washington Naval Treaty was signed, placing restrictions on the building of new naval ships. This led to a decrease in the size of the Japanese Navy.

Interwar period and the start of World War II

In 1923, Kongō was used to transport Crown Prince (later Emperor) Hirohito to an official visit of Taiwan, and over the interwar period saw a number of upgrades. Starting in 1929, the Japanese Empire began transforming Kongō from a cruiser to a full-on battleship, completing the process six years later. The vessel was made to be significantly faster and had the armor near her ammunition magazines strengthened, among a number of other upgrades.

The newly rebuilt ship was active during the Second Sino-Japanese War , with two of her floatplanes bombing the Chinese town of Fuzhou. When the Second World War began, however, Kongō was sent off to the Pacific.

On February 22, 1942, the battleship participated in the Japanese invasion of the Dutch East Indies . The rest of year saw Kongō frequently battling and sinking ships from the British Empire across the Pacific.

The loss of Kongō in the Formosa Strait

For Kongō and Japan, the start of the Pacific campaign went very well. However, the tides turned during the Battle of Midway with the loss of four of the Combined Fleet's aircraft carriers. The ship also took part in the Guadalcanal Campaign , during which Henderson Field was bombarded with high-explosive shells in what was the most successful Japanese battleship action of the Second World War.

The next two major offensives the vessel took part in were the battles of the Philippine Sea and Leyte Gulf . Kongō played an important role in Leyte Gulf, sinking multiple American vessels, including the destroyer escort USS Samuel B. Roberts (DE-413). Despite this, the battle resulted in a victory for the Allies.

Not long after, in November 1944, Kongō was spotted by the submarine USS Sealion (SS-315) in the Formosa Strait. The vessel fired six bow torpedoes at the battleship, two of which hit and flooded Kongō 's boiler rooms. While she was able to escape the scene, the damage proved to be too much, with her sinking to the bottom of the strait after her forward 14-inch magazine exploded. Over 1,200 crewmen died.

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Kongō was the only Japanese battleship to be sunk by a submarine during WWII, while Sealion was the only Allied submarine to sink an enemy battleship.