First Carrier Division
In February 1944, "Shōkaku" and "Zuikaku" were transferred to Singapore. On 1 March the carrier divisions were reorganized with the new fleet carrier replacing "Zuihō" in the division. The First Carrier Division sailed in mid-May for Tawi-Tawi in the Philippines. The new base was closer to the oil wells in Borneo on which the IJN relied and also to the Palau and western Caroline Islands where the Japanese expected the next American attack; the location lacked an airfield on which to train the inexperienced pilots and American submarine activity restricted the ships to the anchorage.