Haruna served the Imperial Japanese Navy (IJN) throughout World War 1 (1914-1918) and World War 2 (1939-1945). She was designed with the assistance of the British and formed the forth ship of the four-strong Kongo-class battlecruiser group. These vessels were commissioned from 1913 to 1915 and managed healthily long service careers spanning from 1913 until 1945. By the end of their time at sea, all but one of the class survived war and this sole example was scrapped after being sunk at her moorings during World War 2. As battlecruisers, theses ships were to serve in the capital ship role and carried large caliber main batteries. Unlike battleships, however, armor protection was sacrificed for speed.
Haruna was ordered in 1911 and Kawasaki Shipyards was commissioned for her construction. Her keel was laid down on March 16th, 1912 and she was launched on December 14th, 1913. The vessel's official commissioning came on April 19th, 1915. Haruna held a displacement value of 36,600 tons (long) and measured 728.3 feet long with a beam of 101.7 feet and a draught of 31.9 feet. Her propulsion machinery constituted 36 Yarrow boilers helping to develop 64,000 horsepower to four shafts underneath the stern. Maximum speed in ideal conditions reached 26 knots. Her profile was consistent with the period, the superstructures amassed around midships and bookended by two main masts with several smoke funnels being featured. A very pointed bow ensured speeds could be maintained in relatively calm seas and onboard space allowed for a crew of 1,360 to be carried. Armor protection included 230mm at the turrets, 200mm at the belt and up to 70mm along the deck.
Armament was a key consideration for the class and the main gun arrangement was made up of 8 x 14" guns in four twin-gunned turrets, two fitted forward and two fitted aft. This marked the first class in the world to feature this large caliber armament as a uniformed main battery. 16 x 6" guns were also fitted and these across sixteen single-gunned turrets set about midships. 8 x 76mm guns were installed as a final line of firepower. The original armament suite was rounded out by the inclusion of 8 x 530mm (21") submerged torpedo tubes - a common trait of pre-World War 1 warships.
Following successful conclusion of her trials period, Haruna was made a part of the Third Battleship Division (Second Fleet) and began service in the East China Sea for her part in World War 1 (1914-1918). Following the war, during September of 1920, an accident at one of the No.1 turret guns killed seven and caused damage to the installation. A faulty fuse on one of the charge bags was blamed for the explosion. She entered reserve status as the world wide military followed all nations with the conclusion of World War 1. The Kongo-class of the IJN was one of the few notable ship groups to survive the naval purge that was seen after the signing of the Washington Naval Treaty. This treaty served to limit naval arms production and help stave off another global conflict precipitated by a major arms race.
Because of the limitations imparted on the IJN by the Treaty, no new capital ships were ordered and built for a time and this forced the service to modernize and modify existing vessels through greater firepower, armor and capabilities. Haruna was selected for such work in mid-1926 and construction took the better part of two years in which her armor was upgraded (notably exceeding the limitations of the Washington Naval Treaty) and internal spaces improved. Torpedo bulges were added along her sides to improve her survivability amidst the growing threat of submarine use around the globe. Her design also accepted three reconnaissance floatplanes. The boiler arrangement was changed to a more modern and efficient design which resulted in the loss of her forward funnel and a resizing of her existing funnel structure. The new machinery increased ocean-going speeds to 30 knots. Because of the changes instituted, Haruna was now reclassified as a battleship. She joined the Forth Battleship Division in 1928 and entered reserve status in 1930.
Japanese aspirations in the region ultimately led to the invasion of Manchuria during September of 1931 and this, in turn, saw the Japanese abolish its signed naval treaties. In August of 1933, Haruna was selected for yet another conversion, this time to become a "fast battleship", with the intent to increase her straight line speed - necessary in keeping up with the growing reliance on aircraft carriers in the IJN. Her bridge superstructure was wholly revised, dimensions redrawn and new machinery installed. Armor protection was improved as well. She was readied for October of 1934 and went to war against China during the Sino-Japanese War of 1937-1945 before being placed in reserve for January 1938. She was then assigned to the Third Battleship Division (First Fleet) for 1941 while December 7th of that year marked the Japanese attack on Pearl Harbor and the American entry into the war - marking a critical junction of the War in the Pacific for the Japanese.
Haruna saw combat actions against the British Navy and supported additional amphibious operations and offshore activities. She entered refit in mid-April and was available by the end of May where she formed part of the strike group sent to Midway for the Battle of Midway (June 1942). This action became a major American victory and a shock to Japanese naval superiority - four of its aircraft carriers were sunk in the melee. Haruna managed to survive and was sent back to Japan for another refit. Haruna then formed part of the protection force for Japanese convoys attempting to strengthen its force at Guadalcanal and her guns were effectively used to shell Henderson while providing a clear path for naval convoys of men, supplies and machines. Because of mounting naval losses, Haruna was recalled to Truk for the remainder of the year lest she too be sunk by persistent American warplanes or warships.
1943 was a relatively quiet time for the vessel and her final notable operational sorties took place during 1944 when she took part in the Battle of the Philippine Sea - another decisive American victory - where she took hits from American bombs. This forced her to Kure for needed repairs and she underwent another refit while there. In October she was part of the attack force during the Battle of Leyte Gulf which ended with the Allied liberation of Leyte Island and resulted in another major Japanese defeat. Haruna managed to survive this action and was pulled back for repairs. She ran aground near Lingga on November 22nd, 1944 which badly damaged her hull and this kept her out of service until early December and was at Kure for January of 1945.
1945 saw her armament revised as 8 x 14" main guns, 16 x 6" guns and 12 x 5" guns along with 108 x 25mm Anti-Aircraft (AA) guns. The latter installation did away with the torpedo tubes featured in the original design as survivability was now the call of the day. IJN authorities reassigned Haruna to the First Battleship division (Second Fleet) in January and placed her at Kure to provide defense against American bomber raids on this critical naval base. One raid resulted in a sole bomb striking Haruna's starboard but she remained a viable fighting ship for the time being. More attacks on the Kure Naval District followed by the Americans in an effort to completely knock out Japanese Navy capabilities for the remainder of the war. Haruna was once again hit but damage was light. A follow-up raid in late July saw her take eight bombs which caused her to sink in the harbor, formally ended her tenure on the sea.
With the war over in August of 1945 and the Japanese surrender signed in September of that year, Haruna lay in place underwater until she was raised in 1946. She was stripped of her usefulness and her hulk scrapped - becoming the only "survivor" of the war concerning the four-strong Kongo-class.