Recalled to Japan in February 1945, Ugaki was appointed commander of IJN Fifth Air Fleet based in Kyūshū and overseeing all naval aircraft in the region from his headquarters in a cave bunker to protect him from the growing threat of B-29 Superfortress attacks. In March, he launched a long-range strike of "kamikaze" against the U.S. fleet anchored at Ulithi followed by the first waves of Operation Ten-Go in April, which involved hundreds of "kamikaze" attacks against U.S. Navy ships in the vicinity of Okinawa. Though such air attacks throughout this campaign caused fearsome superficial damage and crew casualties to a great number of Allied vessels, no Pacific Fleet surface warships larger than a destroyer were sunk directly by this method during the spring of 1945.