Upon commissioning, the
sister ships were assigned to the 1st Battleship Division of the
1st Fleet.
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.
Ise hosted
Edward,
Prince of Wales, and his
aide-de-camp Lieutenant
Louis Mountbatten in 1922 during the prince's visit to Japan. In
Korea Bay when the 1923 Great Kantō earthquake struck, they sailed to
Kyushu where they loaded supplies for the victims on 4 September. Together with two other battleships and a pair of
light cruisers,
Ise sank the
destroyer in 1926 during gunnery practice.
Ises AA armament was upgraded in 1931 and
Hyūgas two years later. The latter ship was modernized in 1934–36 and
Ise in 1935–37, both at
Kure Naval Arsenal. During the Second Sino-Japanese War, the sisters frequently patrolled the Chinese coast in support of the blockade imposed by Japan. In August 1937
Hyūga ferried two
battalions of
Special Naval Landing Forces to
Port Arthur. Three years later, she served as the
flagship for the Emperor of the puppet state of
Manchukuo,
Henry Pu-yi, during his state visit to Japan in June 1940. On 15 November the ships were transferred to the 2nd Battleship Division of the 1st Fleet. The sisters were refitted in late 1940 in preparation for war, which included the fitting of external
degaussing coils and additional AA directors. the sisters sortied for the
Bonin Islands with four other battleships and the
light carrier as distant cover for the fleet attacking
Pearl Harbor, and returned six days later. During gunnery training on 5 May, there was a premature detonation in the left gun of
Hyūgas Turret No. 5 that disabled both guns and killed 51 crewmen. Both aft magazines were flooded to douse the resulting fire and save the ship. 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. On 11 May a valve in
Ises No. 2 engine room stuck in the open position and flooded the engine room. While under repair at Kure, both ships received prototype Type 21 radars. They returned home on 14 June and the IJN began preliminary planning to replace the lost carriers with hybrid carriers converted from battleships. The sisters were selected for conversion and detached from the division on 14 July in preparation. They remained on "standby alert" until the actual conversions began. After completing her sea trials,
Ise was attached to the
Imperial Japanese Naval Academy at
Etajima and ferried troops and munitions to the naval base at
Truk in October. In November the ship began
working up, joined by the newly completed
Hyūga the following month, and both rejoined the 2nd Battleship Division. On 1 May 1944, the sisters were transferred to
Rear Admiral Matsuda Chiaki's reformed
Fourth Carrier Division of the
3rd Fleet.
Battle off Cape Engaño In October 1944, the two ships were involved in the
Battle off Cape Engaño. Shortages of aircraft and serviceability problems greatly retarded pilot training and the ships only had a total of 17 D4Ys and 18 E16As on hand on 1 October; of these, only 6 and 16 were operational, respectively. The Japanese plan for the defence of the Philippines envisioned that the surviving carriers would be used to lure the American carrier forces away from the invasion area to a position where the carriers could be attacked by land-based aircraft, while the transports would be attacked by the rest of the IJN. The other carrier air groups were not in much better shape and the Japanese decided to retain the aircraft ashore for use against the American carriers. The Fourth Carrier Division, including the sisters, fleet carrier and the light carriers , , and , was assigned to the Northern Force under the command of
Vice Admiral Jisaburō Ozawa. The
Ise-class sisters sailed from
Yashima on 20 October. 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. On the morning of 24 October, the group was facing a United States Navy force that included ten carriers containing 600–1,000 aircraft. Ozawa launched the bulk of his few aircraft to attack the American carriers as a distraction. They inflicted no damage and caused the Americans to search in the direction from which they had attacked. The Americans finally spotted the Japanese carriers at 16:40, some east of
Cape Engaño, the northeastern tip of
Luzon. The American carriers were spread out and it was very late in the day to launch an
airstrike, so Admiral
William Halsey, commander of the
Third Fleet decided to mass his carriers in a position to attack the following morning. Ozawa reversed course during the night, correctly believing that the Americans would follow him north. Although they had lost contact during the night, the Americans did find the Japanese carriers at 07:35. They had already launched an airstrike of 180 aircraft that was orbiting ahead of the American carriers while waiting for the Japanese ships to be located. This was just the first of a total of five airstrikes that the Americans launched that day. The sisters were not heavily engaged by the early airstrikes, which instead focused on Ozawa's fleet and light carriers, sinking carriers
Zuikaku,
Chitose and
Zuihō, and the destroyer , while the carrier
Chiyoda and the cruiser were crippled.
Ise claimed to have shot down five attacking dive bombers from the second wave and one small bomb detonated on Turret No. 2.
Hyūga was lightly damaged by near misses that ruptured some hull plating in her bulge and peppered her superstructure with splinters. She took on a 5-degree
list that was quickly corrected before she was ordered to tow
Chiyoda to safety. Her attempt was unsuccessful and
Chiyoda had to be abandoned,
Ise was attacked by 80-odd aircraft from the fourth wave, but they failed to inflict any serious damage. She dodged 11 torpedoes and was only hit by a bomb once, on the bulge outboard of the port catapult. 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. While an exact total of her casualties is not available, it has been estimated that 5 men were killed and some 111–121 crewmen were wounded during this attack. before the Japanese reached Kure on 20 February. The Fourth Carrier Division was disbanded on 1 March and the sisters were reduced to 1st rank reserve ships. On 19 March Kure was attacked by aircraft from
Task Force 58 and
Hyūga was hit three times by bombs that killed 37 men and wounded 52. Her gunners claimed to have shot down one American dive bomber during the attack.
Ise was hit twice during the attack, but her casualties, if any, are unknown. The ships were turned into
floating AA batteries over the next several months although it availed them little when they were attacked again by
American carrier aircraft in July. On the 24th
Ise was struck by five bombs and near missed multiple times; all told she lost 50 crewmen killed and many others wounded. The bombs started numerous leaks and
Ise began to settle by the bow, although she was returned to an even
keel after three days pumping.
Hyūga was a primary focus of the attack and she received 10 direct hits and up to 30 near misses. She was badly damaged with some 200-odd crewmen killed and 600 wounded during the attack. She slowly foundered over the next two days and was not attacked when the Americans returned four days later. This time it was
Ises turn and she was struck 11 or more times with many near misses that put her on the bottom in shallow water with a 15 degree list. The sisters were struck off the
Navy List in November and their wrecks were scrapped after the war. ==Notes==