the D3As attacked shipping in the Sealark Channel. The escorts claimed to have shot down three American aircraft for the loss of one Zero and three dive bombers. Allied naval losses during the entire day included Aaron Ward, the oil tanker , the minesweeper and damage to a transport and another tanker, although it is uncertain which aircraft sank or damaged each ship. A second series of attacks was made against Oro Bay, New Guinea, on 11 April. Jun'yōs 9 Zeros, together with Hiyōs 21 fighters, escorted the latter's D3As. One defending fighter was claimed for the loss of a single dive bomber. The following day, 17 of Hiyōs Zeros provided top cover for several waves of attacks on Port Moresby, New Guinea, her pilots claiming nine victories without losing any of their own. On 14 April, the Japanese attacked Milne Bay, New Guinea, with a large force escorted by 75 Zeros contributed by all the carriers involved. Hiyōs fighter pilots claimed to have shot down three Allied aircraft without loss and the bombers sank two transports. Her air group returned to Truk by 18 April to rejoin the ship. In response to the invasion of Attu Island on 11 May, the Second Carrier Division departed Truk, accompanied by three battleships and two heavy cruisers and reached Japan on 25 May. The Americans recaptured Attu before the fleet could depart to counter-attack. Now the flagship of the Second Carrier Division under Rear Admiral Munetaka Sakamaki, Hiyō departed Yokosuka on 7 June with Junyō en route for Truk. Later that evening, the ship was torpedoed by the submarine off Miyakejima. Hits in the starboard bow and boiler room knocked out all power but she managed to return to Japan the following day after restoring power. Hiyōs fighters were flown to Truk by 15 July and assigned to the light carrier , as were Sakamaki and his staff. While being repaired at Yokosuka until 15 September, more 2.5 cm Type 96 AA guns were installed, and Sumikawa was relieved by Captain Tamotsu Furukawa on 1 September. Two months later, Hiyōs air group was reconstituted in Singapore with 24 Zeros, 18 D3As and 9 B5Ns; the ship departed Japan for Singapore on 24 November. She arrived on 3 December, loaded her air group and was almost immediately assigned duties as an aircraft ferry. On 9 December, Hiyō left Singapore en route for Truk