Following the loss of most of the IJN's large aircraft carriers during the Battle of Midway in mid-1942, they were rebuilt with a flight deck replacing the rear pair of gun turrets to give them the ability to operate an air group of floatplanes.

They participated in the Battle off Cape Engaño in late 1944, where they decoyed the American carrier fleet supporting the invasion of Leyte away from the landing beaches.

Afterwards both ships were transferred to Southeast Asia; in early 1945 they participated in Operation Kita, where they transported petrol and other strategic materials to Japan.

[1] The IJN's fleet of battleships had proven highly successful in 1905, the last year of the Russo-Japanese War, which culminated in the destruction of the Russian Second and Third Pacific Squadrons at the Battle of Tsushima.

[2] In the aftermath, the Japanese Empire immediately turned its focus to the two remaining rivals for imperial dominance in the Pacific Ocean: Britain and the United States.

[1] Satō Tetsutarō, a Japanese Navy admiral and military theorist, speculated that conflict would inevitably arise between Japan and at least one of its two main rivals.

Displacing 17,900 long tons (18,187 t) and armed with ten 12-inch (30.5 cm) guns, Dreadnought rendered all existing battleships obsolete by comparison.

Another issue was that Japanese sailors had problems maintaining a high rate of fire with the 45.36-kilogram (100 lb) shells used in the manually loaded 152-millimetre (6 in) secondary guns used in the Fusō class and earlier designs.

The turbines were designed to produce a total of 40,000 or 45,000 shaft horsepower (30,000 or 34,000 kW) (Hyūga and Ise respectively), using steam provided by 24 Kampon Ro Gō water-tube boilers at working pressures of 13–16.9 kg/cm2 (1,275–1,657 kPa; 185–240 psi).

[32] During the mid-1930s reconstruction, the torpedo tubes were removed and the Vickers two-pounders were replaced by twenty license-built Hotchkiss 2.5-centimetre (1 in) Type 96 light AA guns in 10 twin-gun mounts.

[32] This was the standard Japanese light AA gun during World War II, but it suffered from severe design shortcomings that rendered it a largely ineffective weapon.

The danger from plunging shells at long distances was not appreciated until the fatal magazine explosions of three British battlecruisers during the 1916 Battle of Jutland graphically demonstrated the point.

[39] In addition to the torpedo bulge added when the ships were modernized, the deck armour over the machinery and magazines was increased to a total thickness of 140 mm.

The loss of four Japanese aircraft carriers during the Battle of Midway in June 1942 severely limited the ability of the IJN to provide any air cover and alternatives were sought.

Plans for more elaborate conversions were rejected on the grounds of expense and - more critically - time, and the IJN settled on removing the rear pair of turrets and replacing them with a flight deck equipped with two catapults to launch floatplanes.

[45] During 1944, the ships' AA defences were reinforced with an additional dozen triple and eleven single 25 mm gun mounts, for a total of 104 barrels, and a pair of Type 13 early warning radars were added.

A pair of rotating gunpowder-propelled catapults were fitted on the sides of the hull, forward of the aft superstructure where they partially restricted the arc of fire of the two amidships turrets.

The double bottom below the former positions of aft turrets was converted to hold fuel oil; this increased the ships' endurance to 9,500 nautical miles (17,600 km; 10,900 mi) at a speed of 16 knots.

[32] The removal of the secondary armament, the rear turrets and their supporting structures was generally compensated by the addition of the flight deck, hangar, AA guns and more fuel, and the metacentric height increased 0.23 metres (9.1 in) to 2.81 metres (9 ft 3 in) at full load as a result of the reduction in the displacement by over 2,000 tonnes (2,000 long tons) to 40,444 tonnes (39,805 long tons).

Hyūga had an explosion in one of her main gun turrets that killed 11 men and injured 25 in 1919; the following year she accidentally collided with and sank a schooner, losing two crewmen.

Before the start of the Pacific War, both ships frequently exercised off the coasts of the Soviet Union, Korea and China in addition to training in Japanese waters.

[32] When Japan began the Pacific War on 8 December,[Note 3] the sisters sortied for the Bonin Islands with four other battleships and the light carrier Hōshō as distant cover for the fleet attacking Pearl Harbor, and returned six days later.

[32] On 11 March 1942 Ise and Hyūga sortied from their anchorage at Hashirajima to join the unsuccessful search for the American carrier force that had attacked Marcus Island a week earlier.

She received temporary repairs during which the turret was removed and replaced by a circular armour plate on which three triple 25 mm gun mounts were positioned.

[32] Commanded by Vice-Admiral Shirō Takasu, the 2nd Battleship Division set sail with the Aleutian Support Group on 28 May, at the same time that most of the Imperial Fleet began an attack on Midway Island (Operation MI).

Ozawa's carrier group was a decoy force, divested of all but 108 aircraft, intended to lure the American fleet away from protecting the transports at the landing beaches.

Some 34 other bombs near missed her, spraying her with splinters and ruptured some hull plates that contaminated some fuel oil and caused leaks in her port boiler rooms.

The division sailed for Singapore on 30 December and Vice Admiral Kiyohide Shima transferred his flag to the light cruiser Ōyodo on arrival there the following day.

Its planned return to Japan was delayed by attacks by the American Third Fleet on targets in Indochina and southern China that sank two oil tankers that were intended to refuel the division.

[32] The IJN then decided to use the sisters and their escorts to bring a load of petrol, rubber, tin and other strategic minerals back to Japan after the American carriers departed the South China Sea (Operation Kita).