in November 1943 with landings in the Gilbert Islands. The Japanese were forced to watch helplessly as their garrisons in the Gilberts and then the Marshalls were crushed. The Japanese strategy of holding overextended island garrisons was fully exposed. In February 1944, the US Navy's fast carrier task force attacked the major Japanese naval base of Truk during Operation Hailstone. Although the Combined Fleet had moved its major vessels out in time to avoid being caught at anchor in the atoll, two days of air attacks resulted in significant losses to Japanese aircraft and merchant shipping. The power of the American attack on Truk far surpassed that of the Japanese attack against Pearl Harbor. The IJN was forced to abandon Truk and were now unable to stop the Americans on any front. Consequently, the Japanese retained their remaining strength in preparation for what they hoped would be a decisive battle. Though the Japanese had been leaders in carrier development, at the beginning of the war many of the IJN's top commanders were still battleship or "Big Gun" adherents. However, by early 1944 these commanders had finally accepted the fact that the carrier was the new capital ship. This realization brought with it a change in fleet organization. On March 1, 1944, the First Mobile Fleet was created under the command of Vice Admiral Jisaburo Ozawa. Instead of remaining in separate fleets, most of the front-line battleships, cruisers, and destroyers joined the carriers in the Mobile Fleet. The Japanese finally accepted the concept of entrusting the tactical command of a task force to a carrier admiral, this had been adopted by the Americans almost two years earlier. Admiral Koga survived slightly less than a year as the Commander-in-Chief of Combined fleet. In March 1944, while en route to the Philippines from Palau, his plane disappeared in a storm. Koga's chief of staff, Admiral Shigeru Fukudome, had also left Palau on a separate plane and flew into the same storm. His plane crashed near Cebu, and he was captured by Filipino guerrillas with his documents seized. Although the guerrillas were quickly forced to give up their prisoner, the documents and its coding system found their way to Allied intelligence via an American submarine. After recovering Fukudome, the Japanese realized that their planned operations were compromised and they needed a new one. Admiral Shigetaro Shimada, the Chief of the Naval Staff in Tokyo,