May 1942. They formed the core of the 2nd Carrier Strike Force, part of the Northern Force, tasked to attack the Aleutian Islands, an operation planned to seize several of the islands to provide advance warning in case of an American attack from the Aleutians down the Kurile Islands while the main body of the American fleet was occupied defending Midway. Ryūjōs air group now consisted of 12 A6M2 Zeros and 18 B5Ns, plus two spares of each type. The ship transferred to Mutsu Bay on 25 May and then to Paramushiro on 1 June before departing the same day for the Aleutians. At dawn on 3 June, she launched 9 B5Ns, escorted by 6 Zeros, to attack Dutch Harbor on Unalaska Island. One B5N crashed on takeoff but 6 of the B5Ns and all of the Zeros were able to make it through the bad weather, destroying two PBYs and inflicting significant damage on the oil storage tanks and barracks. A second airstrike was launched later in the day to attack a group of destroyers discovered by aircraft from the first attack, but they failed to find the targets. One Zero from Ryūjō from the second strike was damaged by a Curtiss P-40 and crash landed on the island of Akutan. The aircraft, later dubbed the Akutan Zero, remained largely intact and was later salvaged by the U.S. Navy and test flown. On the following day, the two carriers launched another airstrike, consisting of 15 Zeros, 11 D3As, and 6 B5Ns, which successfully bombed Dutch Harbor. Shortly after the aircraft were launched, the Americans attacked the carriers, but failed to inflict any damage. A Martin B-26 Marauder bomber and a PBY were shot down by Zeros, and a Boeing B-17 Flying Fortress bomber was shot down by flak during the attack. Ryūjō arrived back at Mutsu Bay on 24 June, and departed for the Aleutians four days later to cover the second reinforcement convoy to Attu and Kiska Islands and remained in the area until 7 July in case of an American counterattack. She arrived at Kure on 13 July for a refit and was transferred to Carrier Division 2 a day later. Battle of the Eastern Solomons The American landings on Guadalcanal and Tulagi on 7 August caught the Japanese by surprise. The next day, Ryūjō was transferred to Carrier Division 1 and departed for Truk on 16