the Third Fleet. Mogami returned to Japan, and underwent a major conversion at Sasebo Naval Arsenal from 25 August to an aircraft cruiser to improve the fleet's reconnaissance capabilities. Her No. 4 turret and the damaged No. 5 turret were removed and her aft magazines modified to serve as gasoline tanks and munitions storage. Her aft deck was extended and fitted with a rail system to accommodate the planned stowage of 11 Aichi E16A Zuiun ("Paul") reconnaissance floatplanes. The dual Type 96 25 mm AT/AA Gun and Type 93 13-mm machine guns were replaced by 10 triple mount Type 96s and a Type 21 air-search radar. As the new E16A aircraft were not yet available, three older Mitsubishi F1M2 Type 0 ("Pete") two-seat biplanes and four Aichi E13A1 Type O ("Jake") three-seat reconnaissance floatplanes were embarked. Rebuilding was completed on 30 April 1943, and Mogami was re-commissioned into the First Fleet. . On 22 May, Mogami collided with oiler Toa Maru in Tokyo Bay and was damaged slightly. On 8 June, while at Hashirajima, Mogami was moored near the battleship when the latter exploded and sank. Mogami sent boats to rescue survivors, but they found none. On 9 July 1943, Mogami departed Japan for Truk, with a major convoy of troops and supplies; the task force was unsuccessfully attacked by the submarine , and after reaching Truk, continued on to Rabaul. From August through November, Mogami made numerous sorties from its base at Truk in search of the American fleet and in response to American probing attacks into the Marshall Islands. From 3 November, Cruiser Divisions 4, 7 and 8 were assigned to the Solomon Islands front, to attack American forces off Bougainville. While at anchor at Rabaul on 5 November, Mogami was attacked by a SBD Dauntless dive-bomber from the aircraft carrier and hit by a bomb. She was set on fire and 19 crewmen were killed. After repairs at Truk by the repair vessel , Mogami was ordered back to Japan. While at Kure from 22 December eight more Type 96 single-mount 25-mm AA guns were installed on the aft deck, bringing the total to 38 barrels. Refit was completed by 8 March 1944, and Mogami returned to Singapore a week later. Battle of the Philippine Sea On 13 June 1944, Admiral Soemu Toyoda, CINC, Combined Fleet, activated the "A-Go" plan for the defense of the Mariana Islands.