The Battle of Tinian was a battle of the Pacific campaign of World War II, fought on the island of Tinian in the Mariana Islands from 24 July until 1 August 1944. The 8,000-man Japanese garrison was eliminated, and the island joined Saipan and Guam as a base for the Twentieth Air Force.
A two-prong attack through the Central Pacific and the Philippines was adopted at the 1943 Cairo Conference. Operation Granite II was a U.S. Navy devised strategy of island hopping, calling for the seizure of Saipan, Tinian and Guam. The Gilbert and Marshall Islands had been seized by the summer of 1944, while some Japanese garrisons were left to starve. Following the conclusion of the Battle of Saipan on 9 July, the US began preparations for attacking nearby Tinian.
Tinian was part of Japan's South Seas Mandate. By June 1944, it had a population of 15,700 Japanese civilians, including 2,700 ethnic Koreans and 22 ethnic Chamorro. The Japanese defending the island, the 50th Infantry Regiment, which was originally part of 29th Division, were commanded by Colonel Kiyochi Ogata. On 12 May 1943 there were also 2,349 marines of the 3rd Special Base Force (第 3 特別 根 地 隊, Dai-3 Tokubetsu Konkyochitai) and 950 marines of the 56th Naval Guards, who had been transferred there from Truk. These soldiers were under the command of Captain Goichi Oie. The naval forces took over the defense of the airfields, as they belonged to the facilities of naval aviation. The Japanese naval troops also took over all the heavy artillery guns around the airfields and the 39 heavy anti-aircraft guns, which were set up directly around the slopes. In addition, there were construction crews, flight technicians and staff, for a total of about 4,110 soldiers of various units defending the airfields. Vice Admiral Kakuji Kakuta, commander of First Air Fleet, was headquartered in Manila but was on Tinian on an inspection tour when the invasion started. Kakuta exercised no command authority over the army troops on the island, and the naval troops were not subject to his direct command.