The loss of four Japanese aircraft carriers during the Battle of Midway
in June severely limited the ability of the IJN to conduct operations and alternatives were sought. Plans for full conversions of battleships into aircraft carriers were rejected on the grounds of expense and, most critically, time, so the IJN settled on removing the rear pair of turrets from the Ise
-class ships and replacing them with a flight deck equipped with two rotating catapults. Ise
began her conversion on 23 February 1943 and Takeda was relieved by Captain Hase Shinzaburo on 25 April. The ship's No. 5 and No. 6 turrets were replaced by a hangar surmounted by a flight deck. This was not long enough to permit the launch of aircraft or their recovery. Two catapults were installed and the existing crane was moved to the flight deck. The deck was fitted with an extensive system of rails to link each catapult, the storage positions on the deck and the "T"-shaped aircraft lift
that moved aircraft between the flight deck and the hangar. It had a capacity of nine aircraft, with eleven more stowed on deck, and one on each catapult for a total of twenty-two.
The ship's air group was intended to consist of a dozen each Yokosuka D4Y Suisei dive bombers
(Allied reporting name
"Judy"), modified for catapult launching, and Aichi E16A
reconnaissance aircraft (Allied reporting name "Paul"). The former had to land either on a conventional carrier or on land bases, whereas the E16A could be hoisted back aboard using a crane, after landing on the water near the ship.
During the conversion, all of the 14 cm guns were removed and the ship's anti-aircraft suite was heavily reinforced. The eight 12.7 cm Type 89 guns were supplemented with four additional twin mounts and the existing 2.5 cm Type 96 AA twin-gun mounts were replaced by 19 triple-gun mounts for a total of 57 weapons.
These changes increased the ship's overall length to 219.62 metres (720 ft 6 in) and the removal of the heavy gun turrets and their barbettes reduced her displacement to 39,805 long tons (40,444 t) at deep load, despite the addition of more fuel oil storage. The additional fuel increased Ise
's range to 9,500 nautical miles (17,600 km; 10,900 mi). The weight reductions decreased her draft to 9.03 metres (29 ft 8 in). The crew now numbered 1,463 officers and enlisted men.
The rebuild was officially completed on 8 October 1943 and Ise
made a sortie to Truk
later that month, conveying a detachment of the 52nd Division
and supplies. Hase was promoted to rear admiral
on 1 November and the ship began formally working up
10 days later. Captain Nakase Noboru relieved Hase on 25 December.