The preparations to support these landings included a series of carrier and surface raids by Halsey's Third Fleet against Japanese airfields, ships, and installations from Kyūshū to Hokkaido. Flt. Adm. Chester W. Nimitz, Commander-in-Chief, Pacific Fleet, defined Halsey's mission as to: "attack Japanese naval and air forces, shipping, shipyards, and coastal objectives," and to "cover and support Ryukyus forces." As part of this massive undertaking, McCain sailed with TF 38 from Leyte on 1 July 1945. The three task groups under McCain's command, Rear Adm. Thomas Sprague's TG 38.1, Rear Adm. Gerald F. Bogan's TG 38.3, and Rear Adm. Arthur W. Radford's TG 38.4, each comprised an average of three Essex (CV-9)-class carriers and two small carriers. A replenishment group and an antisubmarine group each included escort carriers.