The Gilbert and Marshall Islands campaign were a series of battles fought from August 1942 through February 1944, in the Pacific theatre of World War II between the United States and Japan. They were the first steps of the drive across the central Pacific by the United States Pacific Fleet and Marine Corps. The purpose was to establish airfields and naval bases that would allow air and naval support for upcoming operations across the Central Pacific. Operation Galvanic and Operation Kourbash were the code names for the Gilberts campaign (in modern Kiribati) that included the seizures of Tarawa and Makin, during the Battle of Tarawa of 20–23 November and the Battle of Makin of 20–24 November 1943. Operation Flintlock and Operation Catchpole were aimed at capturing Japanese bases at Kwajalein, Eniwetok, and Majuro in the Marshall Islands. Background The Imperial Japanese Navy occupied the Gilbert Islands three days after the attack on Pearl Harbor, Hawaii. They built a seaplane base on Makin and dispersed troops along the coastlines of the northern atolls to monitor the Allied forces' movement in the South Pacific. The Marshall Islands is located approximately 220 miles (350 km) northwest of the Gilbert Islands, and had been occupied by the Japanese since World War I as part of the South Seas Mandate. The Japanese regarded the islands as an important outpost for their navy. Allied commanders knew that an eventual surrender of Japan would require penetration of these islands. While commander of the United States Army, General Douglas MacArthur, wanted to push towards the Philippines via New Guinea, United States Navy Admiral Chester W. Nimitz favored a drive across the central Pacific, through the Gilberts, the Marshalls, the Carolines, and eventually the Marianas, which would put American B-29 bombers within range of Tokyo. In addition to forcing the Japanese to fight two fronts against the Allies (Nimitz driving from the east and MacArthur from the south), Nimitz's plan would neutralize the outer Japanese defenses, allowing American ground, naval, and air bases to be stationed there for future attacks against other occupied island groups. These outer islands included the atolls of Tarawa and Makin in the Gilberts, and Majuro, Kwajalein, and Eniwetok in the Marshalls. Gilberts Prelude Japanese forces occupied the Gilbert islands on 9 December 1941, landing troops of the South Seas Detachment on Tarawa (10) and Makin islands (now Butaritari and Makin) (9), a few days