ship conducted training for her aircraft in the Inland Sea until 11 May, when she sailed for Tawi-Tawi in the Philippines. The new base was closer to the oil wells in Borneo on which the Navy relied and also to the Palau and western Caroline Islands, where the Japanese expected the next American attack. However, the location lacked an airfield on which to train the green pilots, and American submarine activity restricted the ships to the anchorage. Battle of the Philippine Sea The Japanese fleet was en route to Guimares Island in the central Philippines on 13 June, where they intended to practice carrier operations in an area better protected from submarines, when Vice Admiral Jisaburō Ozawa learned of the American attack on the Mariana Islands the previous day. Upon reaching Guimares, the fleet refuelled and sortied into the Philippine Sea, where they spotted Task Force 58 on 18 June. The Americans failed to locate Ozawa's ships that day and the Japanese turned south to maintain a constant distance between them and the American carriers as Ozawa had decided on launching his air strikes early the following morning. At this time, the 652nd Naval Air Group consisted of 81 Zeros, 27 D3As, 9 Yokosuka D4Y "Judy" dive bombers and 18 Nakajima B6N "Jill" torpedo bombers, roughly evenly divided among the three ships. The three carriers began launching their first air strike of 26 bomb-carrying A6M2 Zeros, 16 A6M5 Zeros to escort the other aircraft and 7 B6Ns at about 09:30. Most of these aircraft were misdirected and failed to find any American ships, although a dozen persisted in their search and found one of the American task groups. A B6N, 5 bomb-carrying Zeros and an escorting Zero were shot down by the defending fighters and no damage was inflicted on any American ships. A second air strike of 27 D3As, 9 D4Ys, 2 B6Ns and 26 escorting Zeros was launched around 11:00, accompanied by at least 18 A6Ms and B6Ns from Shōkaku and . They had also been given an erroneous spot report and could not find any American ships. The 652nd aircraft headed for airfield at Rota and Guam to refuel while those from the other two carriers returned to them. A pair of Zeros and 6 D4Ys bound for Rota spotted the carriers and en route, but failed to inflict any damage on the American ships while losing